2020 ACVIM Forum On Demand Research Abstract Program

Abstract

The American College of Veterinary Internal Medicine (ACVIM) Forum On Demand and the Journal of Veterinary Internal Medicine (JVIM) are not responsible for the content or dosage recommendations in the abstracts. The abstracts are not peer reviewed before publication. The opinions expressed in the abstracts are those of the author(s) and may not represent the views or position of the ACVIM. The authors are solely responsible for the content of the abstracts. 2020 ACVIM Forum On Demand Research Abstract Program June 10–December 31, 2020 ePoster Presentations Index of Abstracts # Presenting Author Abstract Title CARDIOLOGY C01 Samantha Kochie Effects of Pimobendan on Left Atrial Transport Function in Cats With Hypertrophic Cardiomyopathy (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C02 Caroline Sloan Canine Oblique Angiographic Projections in Dorsal, Left Lateral, and Right Lateral Recumbency (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C03 Joanna Kaplan Effect of Pimobendan on Cardiac and Renal Function in Canine Subclinical Myxomatous Mitral Valve Disease (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C04 Eva Frantz Complications and Outcomes Associated with Epicardial Pacemakers in Cats (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C05 Ananda Pires The Use of Activity Response Settings in Rate Responsive Pacemakers in Dogs: A Retrospective Study (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible/Cardiology Research Abstract Award winner) C06 Lisa Freeman Use of Omics Technologies in the Investigation of Diet‐Associated Dilated Cardiomyopathy (DCM) in Dogs C07 Ryan Fries Evaluation of Myocardial Fibrosis in Cats with Hypertrophic Cardiomyopathy Using Cardiac Magnetic Resonance Imaging C08 Clarke Atkins Renin‐Angiotensin‐Aldosterone System Activation in Hypertensive Cats Receiving Amlodipine C09 Ryan Fries Prevalence of the PDK4 and Titin Gene Mutations in North American Doberman Pinschers C10 Yen Yu Chou Diagnostic Utility of Caudal Vena Cava Measurements in Dogs with Cavitary Effusions or Heart Failure C11 Kathryn Meurs Tricuspid Valve Dysplasia is Associated with a PLA2G4F Variant in the Labrador Retriever C12 Jonathan Stack Evaluation of Galectin‐3 as a Novel Biomarker in Feline Hypertrophic Cardiomyopathy C13 Marlos Sousa Use of Three‐Dimensional Models of Echocardiographic Imaging Planes in the Teaching of Echocardiography C14 Marine Roche‐Catholy Clinical Relevance of Serum Electrolytes in Small Animals with Acute Heart Failure: A Retrospective Study C15 Kursten Pierce Rapid Arteriotomy Site Closure using Preplaced Purse‐string Suture Technique in Dogs C16 Marlos Sousa Correlation of Hepatic Venous Doppler with Right Ventricular Morphofunctional Parameters in Dogs with Pulmonary Hypertension C17 Katrina Cusack Ultrasonographic Assessment of Canine Femoral Vessels: Relationship to Age, Body Size, Sex, and Conformational Measurements. (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible/ACVIM Resident Research Award winner) C18 Joonbum Seo Presence of Gut Dysbiosis in Dogs with Heart Failure: A Pilot Study (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C19 Kimberly Cook Combination Radiation Therapy and Chemotherapy for Right Atrial Masses with Pericardial Effusion in Dogs (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible/Cardiology Research Abstract Award winner) C20 Sienna Drizin Effect of Multi‐Dose Oral Trazodone on Arterial Blood Pressure in Normal Beagles C21 Darcy Adin Prevalence of the Angiotensin‐Converting Enzyme Gene Polymorphism in Dogs C22 Ana Paula Sarraff Left Atrial Function Assessment Using Tissue Motion Annular Displacement in Chronic Mitral Valve Diseased Dogs C23 Gabriela Bahr Arias Electrocardiography in Dogs with Mammary Tumors C24 Sumana Prabhakar Comparison of Heart Rate Obtained using AliveCor Electrocardiography to 24‐hour Holter in Canine Atrial Fibrillation C27 Brittany Stewart Transvenous Thromboembolic Coiling of Feline Patent Ductus Arteriosus (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible) C28 Kaitlin Abbott‐Johnson Comparison of 3D Printing Segmentation Software Programs for Veterinary Cardiology Applications C29 Kim Freid Retrospective Investigation of Diet and Dilated Cardiomyopathy (DCM) in Dogs C30 Arianne Fabella Circulating Cell free DNA in Cats with Hypertrophic Cardiomyopathy and Cardiogenic Arterial Thromboembolism C31 Wan‐Ching Cheng Cellular Localization of Key Proteins Controlling Pro‐fibrotic Pathways in Cats with Hypertrophic Cardiomyopathy C32 Natalia Druzhaeva A Dose‐Ranging Study of Coenzyme Q10 in Dogs with Myxomatous Mitral Valve Disease C33 Yu Ueda Genetic Polymorphisms Impact Platelet Inhibition By Clopidogrel in Cats with Hypertrophic Cardiomyopathy C34 Ashley Sharpe Establishing Normal Reference Intervals for Radiographic, Echocardiographic, and NT‐proBNP Values in Apparently Healthy Kittens (ACVIM Resident Research Award eligible & Cardiology Research Abstract Award eligible/ACVIM Resident Research Award winner) C35 Michael Aherne Clinical Usage and Tolerability of Intravenous Pimobendan in Dogs Suffering from Acute Congestive Heart Failure C36 Maria Lucia Lourenço Evaluation of Cardiac Troponin I in Neonate Dogs Born through Eutocia C37 Akane Yoshikawa Comparison of Different Protamine Doses for Heparin Reversal in Dogs Undergoing Mitral Valve Plasty (MVP) C38 Ryohei Suzuki Layer‐specific Myocardial Function Assessed by Two‐dimensional Speckle‐tracking Echocardiography in Cats with Restrictive Cardiomyopathy C39 Ryohei Suzuki Left and Right Myocardial Function in Dogs with Pulmonary Hypertension Secondary to Mitral Valve Disease C40 Sage Hubert Short‐Term Evaluation of Clinical, Radiographic, and Echocardiographic Effects of Patent Ductus Arteriosus Closure in Dogs C41 Kerry O'Donnell Prevalence of Maine Coon and Ragdoll Associated MYBPC3 Mutations in Feline Population with Hypertrophic Cardiomyopathy C42 Marlos Sousa Role of Echocardiographic Views Adapted for Lung Evaluation in Diagnosis of Pulmonary Edema in Dogs C43 Jessica Joshua Myocardial Transcriptome Profiling in Cats with and without Hypertrophic Cardiomyopathy C44 Yunosuke Yuchi Tricuspid Annular Plane Systolic Excursion Normalized by Right Ventricular Size in Dogs with Pulmonary Hypertension C45 Karla Calderón Olaguivel P‐Wave Terminal force in Dogs with Naturally‐Occurring Myxomatous Mitral Valve Disease C46 Kursten Pierce Real‐time Dosimetry Monitoring in the Interventional Catherization Laboratory C47 Jiwoong Her Pharmacokinetics and Relative Bioavailability of Pimobendan and O‐Desmethyl Pimobendan in Healthy Dogs After Rectal Administration C48 Randolph Winter Repeat Balloon Valvuloplasty for Dogs with Pulmonary Valvar Restenosis C49 Natalia Druzhaeva Congestive Heart Failure Affects Peripheral Blood Lymphocyte Subtypes in Canine Myxomatous Mitral Valve Disease C50 Eric De Madron Mathematical Prediction of Infiniti Medical Standard And Duality Tracheal Stents Deployed Length. C51 Wan‐Ching Cheng Myocardial Lumican is Associated with Fibrosis in Cats with Hypertrophic Cardiomyopathy Phenotype C52 Dmitrii Oleynikov Metabolic Markers of Insulin Resistance in Hypertrophied Myocardium of Cats C53 Marlos Sousa The Effect of Timolol Ophthalmic Solution 0.5% on Systolic Function in Healthy Cats NEUROLOGY N01 Dillon Devathasan Functional Evaluation of Microactuators to Prevent Hematoma Shunt Obstruction in an in vitro Hydrocephalus Model (ACVIM Resident Research Award eligible) N02 Hilary Levitin Pharmacokinetics of a Novel Cytosine Arabinoside Subcutaneous Protocol in Dogs with Meningoencephalomyelitis of Unknown Etiology (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) N03 Rachel Lampe The Bloody Study: Effect of Hemodilution on Cerebrospinal Fluid Analysis in Dogs with Neurological Disease (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) N04 Jaya Mehra The Role of Prophylactic Omeprazole in Dogs Treated Surgically for Thoracolumbar Intervertebral Disc Herniation (ACVIM Resident Research Award eligible) N05 Barbara Lindsay What's Wrong with Rongeuring? Comparing Pneumatic Burr and Rongeuring Techniques for Thoracolumbar Hemilaminectomies. (ACVIM Resident Research Award eligible) N06 Amy Yanke Pharmacokinetics of Mebendazole in Canine Plasma and Cerebrospinal Fluid: A Pilot Study N07 Yoonhoi Koo Evaluation of Serum High‐Mobility Group Box 1 Concentration in Dogs with Epilepsy N08 Dawn Boothe Cannabidiol Disposition After Single Oral Dosing in Fasted and Fed Dogs N09 Sarah Deluty The Use of Magnetic Resonance Spectroscopy to Differentiate Canine Brain Masses N10 R. Timothy Bentley Magnetic Micro‐Actuator Enabled Catheters for Ventriculoperitoneal Shunting: Magnetic Resonance Safety and Artifacts N11 Masayasu Ukai Evaluation of “Underreporting of Seizures” with Electroencephalography (EEG) in Canine Epilepsy N12 Melissa Lewis Juvenile‐Onset Motor Polyneuropathy in Siberian Cats N13 Jiwoong Her Relationship between Admission Variables in Dogs with Brain Herniation: A Retrospective Study in 54 Dogs N14 Lauren Green Serum and Cerebrospinal Fluid GFAP and pNF‐H Concentrations in Dogs with Meningoencephalomyelitis of Unknown Etiology (ACVIM Resident Research Award eligible) N15 Alison Little Comparing Baseline T‐cell Activation, by IL‐2 Expression, between Dogs with Immune‐meditated Diseases and Healthy Dogs (ACVIM Resident Research Award eligible) N16 Michal Hazenfratz Potential Use of Dry Surface Electrodes for Electroencephalography (EEG) in Dogs N17 Megan Lin Evaluation of Three‐Dimensional Printing and Virtual Rendering as Teaching Tools for Cerebrospinal Fluid Collection N18 Curtis Dewey Aging Dogs with Spontaneous Brain Microhemorrhages Have Diminished Interthalamic Adhesion Size: A Comparative MRI Study N19 Curtis Dewey Canine Cognitive Dysfunction Patients Have Reduced Hippocampal Volumes Compared with Aging Controls: An MRI study N20 Shintaro Kimura Molecular Insights Into Protein Aggregation of Mutant Superoxide Dismutase 1 in Degenerative Myelopathy. N21 Nana Tanaka Prion‐Like Propagation of Mutant Superoxide Dismutase‐1 in Canine Degenerative Myelopathy N22 Christopher Mariani 3D Printed Drill Guides for Canine Thoracic Spinal Surgery N23 Solene Diop Prevalence of Radiculopathies Associated with Type 1 Intervertebral Disc Disease on MRI in Dogs N24 Danny Sack Impact of von Willebrand Factor on Dogs with Hansen Type 1 Disc Extrusions N25 Rell Parker Development of a Non‐Invasive Diagnostic Technique to Assess Neuromuscular Disease N26 Wojciech Panek Correlation between Canine Cognitive Dysfunction Clinical Metrology Instruments, Cognitive Testing and Plasma Neurofilament Light Concentrations ONCOLOGY O01 Valérie Freiche Feline T‐Cell Low‐Grade Intestinal Lymphoma: A Novel Model of Lymphomagenesis According to the One‐Health Concept O02 Carissa Norquest External Beam Radiation Therapy for the Treatment of Canine Appendicular Osteosarcoma: 77 Cases (Early Career Clinical Oncology Research Award eligible) O03 Adrienne Cheney Evaluation of the Association between Interleukin‐6 and Thrombopoietin Concentrations with Thrombocytosis in Dogs with Carcinoma (ACVIM Resident Research Award eligible) O04 Hannah Able Prognostic Utility of Computed Tomography Radiomic Features for Canine Lung Tumors: An Analytical Study (ACVIM Resident Research Award eligible & Early Career Clinical Oncology Research Award eligible/Early Career Clinical Oncology Research Award winner) O05 Emily Rout High Ki67 Expression is Associated with Poor Prognosis in Canine B‐cell Chronic Lymphocytic Leukemia O06 Klaudia Polak Clinical Differences in Aberrant Feline T‐cell Leukemia Phenotypes O07 Christina Jeffries Characterization of Monoclonal Gammopathies in Patients with Normal Total Proteins O08 Akiyoshi Tani Exosomes Derived From Canine Lymphoma Cells Induce M1 Polarization of Monocytes. O09 Kelly Makielski The VIGOR Clinical Trial: Anti‐Tumor Immunity Induced by Neoadjuvant Oncolytic Virotherapy in Spontaneous Osteosarcoma O10 M. Carolina Duran Successful Treatment of Cutaneous Neoplasias with Electrochemotherapy in Horses O11 Fabio Teixeira Inflammatory Response and Body Composition of Bitches with Breast Tumor Supplemented with Omega‐3 and Glutamine O13 Elizabeth Snyder Targeted Therapy Pevonedistat Promotes Canine Melanoma Cell Death Through DNA Replication and Senescence (VCS Award Winner) O14 Daniela Korec Receptor Tyrosine Kinase Dysregulation and Biological Activity of Toceranib against Canine Urothelial Carcinoma Cell Lines (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) O15 Kate Taikowski Plasma Cytokeratin 18 and Fecal Alpha‐1 Antitrypsin Concentrations in Dogs with Osteosarcoma Receiving Carboplatin Chemotherapy (ACVIM Resident Research Award eligible) O16 Shirley Chu A Virome Sequencing Approach to Feline Oral Squamous Cell Carcinoma to Evaluate Causative Factors (VCS Award Winner) O17 Pamela Jones Concurrent Treatment of Multiple Canine Mast Cell Tumors with Intratumoral Tigilanol Tiglate O18 Fernanda da Costa Arterial Thromboembolism of Metastatic Malignant Neoplasm Origin in Two Cats O19 Tomoko Okusa Anticancer Drug Treatment Increases Cancer Stem Like Cells in Canine Lymphoma Cells SMALL ANIMAL INTERNAL MEDICINE – ENDOCRINOLOGY EN01 Deirdre Mullowney Treatment Failure in Hyperthyroid Cats Following Radioactive Iodine (I‐131) Injection (ACVIM Resident Research Award eligible) EN02 Michelle Miller Day‐to‐Day Variability of Porcine Lente, Insulin Glargine u300 and Insulin Degludec in Diabetic Dogs (ACVIM Resident Research Award eligible) EN03 Luca Giori Iatrogenic Effect of Trilostane (Vetoryl) on Adrenal Steroids Synthesis in Dogs EN04 Carly Patterson Evaluation of a Flash Glucose Monitoring System in Dogs with Rapidly Changing Glucose Concentrations EN05 Allison O'Kell Evaluation for Type 1 Diabetes Associated Autoantibodies in Diabetic and Non‐Diabetic Australian Terriers and Samoyeds EN06 Rebecca Silveston‐Keith The Efficacy, Sensitivity, and Specificity of a Saliva Glucose Monitoring System for Diabetic Canines EN07 Eve Tièche Organoid Cultures of Follicular‐Cell Thyroid Carcinoma: A Novel Canine Model for Translational Thyroid Cancer Research (ESVE Award Winner) EN08 Vanessa Fonseca Measurement of Pre‐trilostane Salivary Cortisol in Dogs with ACTH‐dependent Hyperadrenocorticism EN09 Thomas Schermerhorn Insulin Expression Patterns in Canine Insulinoma EN10 Jeong‐Mi Kim Evaluation of Salivary Vasopressin as an Acute Stress Biomarker in Dogs with Noise Stress EN11 Jeremy Evans Chronic Low‐Dose Rapamycin Does not Affect Glucose and Insulin Regulation in Middle‐Aged, Large Breed Dogs SMALL ANIMAL INTERNAL MEDICINE – GASTROENTEROLOGY GI01 Martin Granick Incidence of Bacteremia Secondary to Colonoscopy in Dogs (ACVIM Resident Research Award eligible) GI02 Marc Myers Low‐fat diet appears to be effective monotherapy in some dogs with protein losing enteropathy (ACVIM Resident Research Award eligible) GI03 Kathryn Robb Outcome for Cats with Chronic Enteropathy Diagnosed Through Endoscopic Intestinal Biopsies (ACVIM Resident Research Award eligible) GI04 Susan Mehain Videofluoroscopic Assessment of Liquid Sildenafil as a Treatment for Canine Generalized Megaesophagus (ACVIM Resident Research Award eligible) GI05 Rachel Pilla Omeprazole Induces Reversible Fecal Dysbiosis in Healthy Dogs GI06 Naila Telles Evaluation of Feline Gastrointestinal pH and Transit Times GI07 Emerald Rodriguez Bacteria Viability in Stored Canine Feces for use in Fecal Microbiota Transplantation GI08 Aarti Kathrani Clinical Effectiveness of Hydrolyzed Diets for Chronic Gastrointestinal Signs in Cats Under Primary Veterinary Care GI09 Melanie Werner Diagnostic Value of Fecal Bacteriologic Culture and Dysbiosis Index in Dogs with Chronic Diarrhea GI10 Susan Jones The Effect of Combined Carprofen and Omeprazole Administration on Gastrointestinal Permeability and Injury in Dogs GI11 Megan Grobman Objective Evaluation of Deglutition in Healthy Cats Using a Free‐Feeding Videofluoroscopic Swallow Study Protocol GI12 Kenjiro Fukushima Mycophenolate Mofetil Effect on the Gastrointestinal Microbiome in Dogs GI13 Alexander Saver Effect of Fasting on the Gastrointestinal Panel in Healthy Dogs (ACVIM Resident Research Award eligible) GI14 Kathryn Hogan Adverse Effects and Impact on Microbiome in Healthy Dogs Treated with Omeprazole (ACVIM Resident Research Award eligible) GI15 Dawn Kingsbury Defining Healthy. The Utility of Building a Companion Animal Fecal Microbiome Reference Dataset GI16 Maria Jugan Relationship between Anemia, Iron Status, and Cobalamin Status in Cats with Chronic Gastrointestinal Disease GI17 Amanda Blake Metronidazole‐Induced Dysbiosis Alters Fecal but not Serum Amino Acid Profiles in Healthy Dogs GI18 Rachel Pilla Chronic Enteropathy Has Bigger Impact Than Diet or Country of Residence on Canine Fecal Dysbiosis GI19 Fabio Teixeira Comparison of the Fecal Microbiota between Healthy Dogs and Dogs with Diabetes Mellitus GI20 Katie Tolbert Understanding the Failure of Oral Acid Suppressants in Cats GI21 Sichao Mao Phenotypic and Functional Characterization of Adult Intestinal Organoids From Dogs with Inflammatory Bowel Disease GI22 Monique Engelbrecht Increased Mean Platelet Volume in Dogs with Canine Parvoviral Enteritis GI23 Megan Grobman Proteomic Characterization of Feline Gastric Fluid to Detect Protein Biomarkers of Reflux and Aspiration GI24 Patricia Eri Ishii Assessment of Intestinal Permeability in Dogs with Chronic Enteropathy GI25 Romy Heilmann Effects of Clinical Characteristics and Lifestyle Factors on Fecal Canine S100/Calgranulin Concentrations GI26 Romy Heilmann Association of Hypercobalaminemia with Pathological Findings in Dogs and Cats GI27 Sue Yee Lim 1,2‐o‐dilauryl‐rac‐glycero‐3‐glutaric acid‐(6′‐methylresorufin) ester (DGGR) Lipase Assay is not Specific for Feline and Canine Pancreatic Lipase GI28 Brogan Atkinson Markers of Endothelial Activation and Inflammation in Canine Parvoviral Enteritis GI29 Stacie Summers The Impact of Sampling Method on Gut Microbial Community Profiles in Dogs and Cats GI30 Fernanda da Costa Spontaneous Gastroduodenal Perforations in Five Cats GI31 Jacqueline Whittemore Fecal Microbiome and Metabolomic Changes in Dogs Receiving Antibiotics Followed By Placebo or Synbiotics GI32 George Lubas Concurrent Gastrointestinal Signs in Hypothyroid Dogs GI33 Jenny Stiller Feasibility and Complications of Video Capsule Endoscopy in 38 Dogs with Suspected Gastrointestinal Bleeding (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) GI34 Jeremy Kiene Use of a Synbiotic for Treating Antibiotic‐induced Diarrhea in Cats GI35 Craig Webb Comparing Adipose‐Derived Mesenchymal Stem Cells to Prednisolone for the Treatment of Feline Inflammatory Bowel Disease GI36 Evangelia Stavroulaki Antibiotic Administration Results in Long‐term Changes to the Immature Feline Fecal Microbiome GI37 Sara Wennogle Coagulation Status, Fibrinolysis, and Platelet Dynamics in Dogs with Chronic Inflammatory Enteropathy GI38 Sergi Segarra Enhanced Gut Microbial Fermentation and Metabolism by Different Starch‐Rich Products in a Canine Gastrointestinal Model. GI39 Stefanie Kather Increased Expression of the Ileal Cobalamin Receptor in Hypocobalaminemic Dogs with Idiopathic Inflammatory Bowel Disease SMALL ANIMAL INTERNAL MEDICINE – HEMATOLOGY HM01 Michael Barchilon Immune Profiles of Cocker Spaniels and Old English Sheepdogs, Breeds Predisposed to Autoimmune Blood Disorders (ACVIM Resident Research Award eligible) HM02 Aria Guarino Comparison of Direct Venipuncture versus Peripheral Catheter Samples for Serum Biochemistry Testing in Dogs (ACVIM Resident Research Award eligible) HM03 Audrey Keebaugh Evaluation of Hemostasis in Hyperthyroid Cats (ACVIM Resident Research Award eligible) HM04 Alison Thomas‐Hollands Effect of Duration of Canine Blood Storage on Red Blood Cell Alloimmunization and Compatibility Testing (ACVIM Resident Research Award eligible) HM05 Robert Goggs Cryopreserved Platelets versus Lyophilized Platelets for Management of Thrombocytopenia Associated Bleeding in Dog HM06 Allison Rowland Inhibition of Myristoylated Alanine‐Rich C Kinase Substrate (MARCKS) Decreases Canine Clot Retraction and Platelet Aggregation HM07 Kathryn LaQuaglia Neutropenia in dogs receiving vincristine for treatment of immune‐mediated thrombocytopenia HM08 Kate KuKanich Evaluation of Hematocrit in Juvenile Shelter Dogs Presenting for Routine Ovariohysterectomy or Neuter HM09 Armelle deLaforcade Point of care assessment of fibrinolysis using the Viscoelastic Coagulation Monitor HM10 Andrew Woolcock Reactive Oxygen Species Production and Biomarkers of Oxidative Stress in Anemic Dogs HM11 Marie Binvel Identification of Five New Feline Erythrocyte Antigens Based on the Presence of Naturally Occurring Alloantibodies (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) HM12 George Lubas Comparison of Dogs Treated for Primary Immune‐Mediated Hemolytic Anemia in Tuscany, Italy and Texas, USA HM13 Jeremy Evans Chronic Low‐dose Rapamycin does not cause Red Blood Cell Microcytosis in Middle‐aged, Large Breed Dogs SMALL ANIMAL INTERNAL MEDICINE – HEPATOLOGY HP01 Michelle Pavlick Evaluation of Coagulation in Dogs with Gallbladder Mucoceles HP02 Robert Kyle Phillips Dogs with Chronic Hepatitis Have Altered Amino Acid Profiles Compared to Healthy Dogs HP03 Kirsten Cooke Gastroduodenal Ulceration in Canine Liver Disease HP04 Punyamanee Yamkate Intracellular Distribution of Copper in Liver Specimens From Cats HP05 Karah Burns DeMarle Approach to the Diagnosis of Hepatocutaneous Syndrome in Dogs: A Retrospective Study and Systematic Review HP06 Elizabeth Schooley Validation of an In‐Clinic Assay for the Measurement of Canine and Feline Bile Acids SMALL ANIMAL INTERNAL MEDICINE – IMMUNOLOGY IM01 Corie Borchert RNA Sequencing of Dogs with Primary Immune‐Mediated Hemolytic Anemia (ACVIM Resident Research Award eligible) IM02 George Moore Proteomic Analysis of Canine Vaccines IM03 Vivian Pedrinelli Gene Expression of Immunoinflammatory and Immunological Status of Obese Dogs Before and After Weight Loss IM04 Maggie Williams Effect of Distemper‐Adenovirus‐2‐Parainfluenza‐Parvovirus Vaccination on Platelet Numbers and Development of Anti‐Platelet Antibodies in Healthy Dogs (ACVIM Resident Research Award eligible) SMALL ANIMAL INTERNAL MEDICINE – INFECTIOUS DISEASE ID01 Taylor Gin Canine Leishmaniasis in North America: Imported and autochthonous Cases, 2006–2019 (ACVIM Resident Research Award eligible) ID02 Amber Graham Heterobilharzia Americana Infection in Dogs: Clinical Features and Outcome in 60 Cases (2010–2019) (ACVIM Resident Research Award eligible) ID03 Ellen Ratcliff Evaluation of Canine Parvovirus Neutralizing Antibody (KIND‐030) as a Prophylactic and Therapeutic Treatment in Puppies ID04 Barbara Qurollo A Novel Rickettsia species Infecting Febrile Dogs in the United States ID05 Erin Lashnits Flea‐Borne Bacterial Pathogens From Free Roaming Cats and Their Fleas ID06 Stephen Cole The “Backyard” Identified as an Environmental Reservoir of blaNDM‐5 E. coli During a Veterinary Outbreak ID07 Madeleine Stein Knowledge, Attitudes and Influencers of Dog‐Owners Surrounding Antimicrobials and Antimicrobial Stewardship in North America ID08 Andrew Sun Serum 25‐Hydroxyvitamin D and Canine Infectious Respiratory Disease Complex in Shelter Dogs ID09 Brogan Atkinson Markers of Inflammation and Cytokine Concentrations During Experimental Babesia rossi Infection of Beagle Dogs ID10 Krystle Reagan Effect of Probiotic Containing Aspergillus‐derived Ingredients on Serum and Urine Galactomannan Antigen Assay in Dogs ID11 Elizabeth Jenkins Feline Parvovirus Seroprevalence Is High in Cats From Disease Outbreak and Non‐Outbreak Regions in Australia ID12 Stephen Cole Point Prevalence Surveys to Investigate a Veterinary Hospital Outbreak of Carbapenem Resistant Escherichia coli ID13 Ellen Ratcliff Pilot Pharmacodynamic and Safety Study of Canine‐Parvovirus‐Neutralizing‐Antibody (KIND‐030a and KIND 030b) in Purpose Bred Puppies ID14 Sarah Sweet Using Big Data to Investigate Feline Intestinal Parasitism by Geographic Region and Age ID15 Pierce Chan Pilot Study to Determine whether Cytauxzoon felis has Expanded into Colorado ID16 Michael Lappin Prevalence of Ehrlichia canis Antibodies in Dogs in Baja Sur, Mexico ID19 Ye‐In Oh Etiology and Seasonality of Fecal Enteropathogens From Diarrheic Cats: A Retrospective Study of 1620 Cases ID20 Cindy Sotelo Vaccination History in Dogs with Acute Respiratory Disease Suspected to be Associated with Parainfluenza Virus (ACVIM Resident Research Award eligible) ID21 Anna Winner The Role of Streptococcus equi Subspecies Zooepidemicus and Influenza Viruses in URIs in Shelter Cats ID22 Krystle Reagan Evaluation of the Clinical Performance of a Point‐of‐Care Coccidioides Antibody Tests in Dogs ID24 Cara Martin In Vitro Inhibitory Effects of Polyammonium Bisulfate and Nanosulfur Against Canine Isolates of Pythium insidiosum SMALL ANIMAL INTERNAL MEDICINE – NEPHROLOGY/UROLOGY NU01 Jennifer MacLeay Urine Specific Gravity is Less Predictive than Nutritional Factors for Management of Urolithiasis in Cats NU02 Lynn Little Voided Urine Collection Methods for Urine Culture in Female Dogs with Lower Urinary Tract Signs (ACVIM Resident Research Award eligible) NU03 Adeline Betting Reticulocyte Indices for the Assessment of Iron Status in Cats with Chronic Kidney Disease (ACVIM Resident Research Award eligible) NU04 Mathieu Paulin Association Between Hyperlipidemia and Lower Urinary Tract Calcium Oxalate Stones in Dogs: Initial Results NU05 JoAnn Morrison Predicting Early Risk of Chronic Kidney Disease in Dogs NU06 Stacie Summers Alterations of Serum Amino Acid Profiles in Cats with Chronic Kidney Disease NU07 Alex Kennedy Feline Ureteral Obstruction: a Case‐control Study of Risk Factors (2016–2019) NU08 Rebekah Mack‐Gertig The probability of persistence of an increased SDMA in Cats and Dogs NU09 Lucy Kopecny Association Between Ultrasound And Renal Biopsy Features In Dogs With Protein‐losing Nephropathy NU10 JD Foster Comparison of Dipstick Salivary and Blood Urea Nitrogen Measurement to Diagnose Azotemia in Dogs NU11 Rebekah Mack‐Gertig Agreement of Renal Biomarkers: Longitudinal Evaluations of Increased SDMA and Creatinine in Cats and Dogs NU12 Jean‐Sebastien Palerme Changes in Symmetric Dimethylarginine and Glomerular Filtration Rates in Dogs Receiving Oral Prednisone NU13 Kate KuKanich Evaluation of Feline Urine Concentrations of Amoxicillin and Clavulanate NU14 Max Emanuel The Clinical Presentation and Outcome Using Various Treatment Modalities in 11 Dogs with Proliferative Urethritis NU15 Jessica Himelman Symmetric Dimethylarginine and Creatinine Concentrations in Cats with Ureteral Obstruction Before and After Decompression NU16 Jessica Hokamp Identification of a Potential Marker of Immune Complex Mediated Glomerulonephritis in Canine Urine NU17 Stacie Summers Influence of a Meal on Serum Concentrations of Gut‐Derived Uremic Toxins in Healthy Adult Cats NU18 Yann Quéau Dietary Potassium Chloride Promotes Urine Dilution and Lowers Relative Supersaturation in Dogs and Cats NU19 Rebecca Geddes The Effect of Attenuating Dietary Phosphate Restriction in Cats with Azotemic CKD and Ionized Hypercalcemia NU20 MICHAEL Wood Urinary Fibrinogen and the Development of Enterococcus spp. Bacteriuria in Dogs NU21 Matthew Miller The Effects of Calcifediol Supplementation on the Renin‐Angiotensin‐Aldosterone System in Dogs with Chronic Kidney Disease (ACVIM Resident Research Award eligible) NU22 Edward Vasquez The Use of a 3D‐Ultrasound Device to Investigate Urinary Retention in Hospitalized Dogs. NU23 Hilla Chen Urethral Tissue Engineering for Canine Urinary Incontinence NU24 Vivian Pedrinelli Influence of Laboratory Parameters on Survival in Dogs with Chronic Kidney Disease NU25 Jennifer MacLeay Reduced Dietary Sodium and Calcium Improves Urine Stability in Dogs NU26 Stacie Summers Fecal Primary and Secondary Bile Acids in Cats with Chronic Kidney Disease NU27 Andrew Woolcock Urinary 15‐F2‐Isoprostanes in Dogs with Transitional Cell Carcinoma and Other Lower Urinary Tract Disease NU28 Ira Roth Transient Increase in Serum Symmetric Dimethylarginine Level During Anesthesia in Cats Undergoing Routine Dental Procedures NU29 Sarah Jones Survey of Litter Box Defecation Habits in Apparently Healthy and Chronic Kidney Disease Cats NU30 Nicole Gibbs Survey of the Practice of Canine and Feline Urinalyses in the United States and Canada NU31 Ya li Chang Plasma Copeptin Concentrations in Dogs with Chronic Kidney Disease NU32 Syu‐Yin Lin Plasma Copeptin Concentrations in Cats with Naturally Occurring Chronic Kidney Diseases NU33 Elisa McEntee Evaluation of Ultrasonographic and Biochemical Parameters to Predict Outcome After Treatment of Feline Ureteral Obstructions. (ACVIM Resident Research Award eligible) NU34 Yann Quéau High‐Protein Diet Does Not Affect Markers of Kidney Function in Cats with Asymptomatic Hypertrophic Cardiomyopathy NU35 Kenny Siu 16S Ribosomal RNA Gene Amplification of Urine from Cats with Suspected Renal Dysfunction (ACVIM Resident Research Award eligible) NU36 Selena Tavener Expression Patterns of Krüppel‐Like Factors (KLFfs) in Renal Tissue in Felines with Kidney Dysfunction NU37 Gwendoline Chaix Intra‐Individual Variability of Urinary Calcium to Creatinine and Oxalate to Creatinine Ratios in Cats NU38 Gwendoline Chaix Intra‐Individual Variability of Urinary Calcium to Creatinine and Oxalate to Creatinine Ratios in Dogs NU39 Alice Defarges Tetrasodium EDTA: An Efficient Chemolytic Agent for Dissolution of Feline and Canine Uroliths In Vitro NU40 Dasol Park Investigation on Urinary and Serum Alpha Klotho in Dogs with Chronic Kidney Disease SMALL ANIMAL INTERNAL MEDICINE – NUTRITION/METABOLISM NM01 Sarah Dodd Comparison of Essential Nutrients in Plant‐Based Pet Foods with Nutrient Requirements of Dogs and Cats NM02 Stacie Summers Evaluation of Nutrient Content and Caloric Density in Commercially Available Foods Formulated for Senior Cats NM03 Mariana Porsani Canine Obesity Knowledge among Brazilian Owner's is Associated to Overweight Risk in Dogs SMALL ANIMAL INTERNAL MEDICINE – OTHER OT01 Lucy Chou The Dog Aging Project Study Population—An Initial Look At the Members of the Pack OT02 Jung‐Hyun Kim Scoring of Erythema, Excoriation, and Lichenification Severity in Canine Atopic Dermatitis Using Deep Learning SMALL ANIMAL INTERNAL MEDICINE – PHARMACOLOGY P01 Emery Jones An in vitro Evaluation of Intravenous Lipid Emulsion on Three Common Canine Toxicants (ACVIM Resident Research Award eligible) P02 Ann Gaier Pharmacokinetic Interactions of Carprofen and Omeprazole in Dogs P03 Butch KuKanich Clinical Efficacy of a Long‐acting Subcutaneous Methadone Solution for Postoperative Analgesia in Dogs P04 Aaron Rozental Pharmacokinetics and Safety of Orally Administered Cannabidiol in Domestic Cats P05 William Love Predicting Uropathogen Identity and Susceptibility Using Patient Signalment and Urine Biochemical Tests P06 Butch KuKanich Efficacy of Long‐acting Methadone Using a Combination of Oral and Injectable Formulations in Perioperative Dogs P07 Jennifer Slovak Clinical Assessment of Transdermal Gabapentin in Cats P08 Laura Tucker Pharmacokinetics, Sedative, and Physiological Effects of Trazadone in Cats Alone Or in Combination with Gabapentin P09 Heta Turunen The Influence of Butorphanol on the Sedative and Cardioventilatory Effects When Coadministered Intramuscularly with Medetomidine‐Vatinoxan P10 Rebekah Strunk Pharmacokinetics of Cannabinoids from Industrial Hemp Oil in Felines P11 Samantha Duxbury Evaluation of Proton Pump Inhibitor Use in Canine Patients Hospitalized in a Tertiary Referral Hospital P12 Jeremy Evans The Pharmacokinetics of Long‐Term, Low‐Dose Oral Rapamycin in Healthy, Middle‐Aged, Medium‐to‐Large Breed Dogs P13 Jeremy George Variability in Plasma Cannabidiol Concentrations in Dogs Receiving CBD‐Containing Products P14 Dong‐hyuk Kwak Pharmacokinetics and Diuretic Effect of Intravenous, Tablet, Developed Oral Disintegrating Film of Furosemide in Dogs SMALL ANIMAL INTERNAL MEDICINE – RESPIRATORY R01 Daniela Bedenice Use of an In‐vitro Larval Motility Assay evaluating Anthelmintic Efficacy against Canine and Feline Metastrongyloids (ACVIM Resident Research Award eligible) R02 Dylan DeProspero Whole Genome Sequence Analysis of Yorkshire Terriers with Tracheal Collapse: Identification of an Associated Variant R03 Tekla Lee‐Fowler Detection of Canine Nasal Disease using Infrared Thermography R04 Jennifer Howard Documenting Bacterial Infection in Canine Aspiration Pneumonia R05 Elizabeth Rozanski Six Minute Walk Test in West Highland White Terriers with Pulmonary Fibrosis R06 Yukihito Shiroshita Laryngotracheobronchoscopy Via Laryngeal Mask Airway in Cats and Dogs: A 16‐Year Experience R07 Henna Laurila Quantitative Proteomics of Bronchoalveolar Lavage in West Highland White Terriers with Canine Idiopathic Pulmonary Fibrosis R08 Elizabeth Rozanski Impact of Spacer Design on Drug Delivery and Potential Drug Cost Implications EQUINE E02 Anna Hammond Heart Rate Variability During Exercise and Recovery in Thoroughbred Racehorses Presented for Poor Performance (ACVIM Resident Research Award eligible) E03 Ludovic Tanquerel Repeatability and Reproducibility of Collapsibility Index of Jugular Veins in Healthy Adult Horses: Pilot Study. E04 Gayle Hallowell Factors Affecting Cardiac Auscultation in the Horse E05 Francesca Worsman Comparison of Two‐Dimensional versus Three‐Dimensional Echocardiography for Assessment of Left Atrial Volume in Thoroughbred Racehorses E06 Gayle Hallowell Influence of Stethoscope on Cardiac Auscultation in the Horse E07 Charlotte Hopster‐Iversen Effects of Short‐Term Induced Atrial Fibrillation on Atrial Function After Cardioversion E08 Melodie Schneider Can the Frequency of Vagally‐Mediated Arrhythmias after Conversion Predict Atrial Fibrillation Reoccurrence in Horses? E09 Rikke Buhl New Diagnostic Opportunities for Diagnosing Paroxysmal Atrial Fibrillation in Horses E10 Elizabeth Finding Phenotypic and Functional Characterization of Equine Endothelial Cells E17 Katharyn Mitchell Poincaré Plots as a Visual Measure of Heart Rate Variability in Healthy Horses E18 Joanne Haughan Novel Mobile Applications Enable Wearable Devices to Yield Accurate Exercising ECG and Heart Rate Data in Horses E19 Babetta Breuhaus Plasma and Urine Aldosterone in Normal Horses and Horses with Subclinical Valve Disease E20 Sarah Schale Seasonal Variation of Endogenous Adrenocorticotropic Hormone (ACTH) in Healthy Non‐Geriatric Donkeys in Northern California (ACVIM Resident Research Award eligible) E21 Jacob Swink Androgens and Estrogens in Healthy and Hospitalized Neonatal Foals (ACVIM Resident Research Award eligible) E22 Jacob Swink Effect of Altrenogest Administration to Pregnant Mares on the Endocrine Profile of Their Foals (ACVIM Resident Research Award eligible) E23 John Haffner The Effect of Trailering and Dentistry on Resting Adrenocorticotropic Hormone Concentration in Horses E37 Kathryn Timko Diagnostic Evaluation of Insulin and Glucose Dynamics in Light Breed Horses with Experimentally‐Induced Insulin Dysregulation (ACVIM Resident Research Award eligible) E38 Kristen Thane Effect of Early or Late Sampling on Thyrotropin‐Releasing Hormone (TRH) Stimulation Test Results E39 Sarah Colmer Cartilage Oligomeric Matrix Protein Differential Expression in Lamellar Tissue from Prolonged Euglycemic Hyperinsulinemic Clamp Model (ACVIM Resident Research Award eligible) E41 Caroline McKinney Assessment of Clinical and Microbiota Responses to Fecal Microbial Transplantation in Horses with Diarrhea (ACVIM Resident Research Award eligible) E42 Jessica Wise The Bioavailability and Efficacy of a Novel Omeprazole Product in Horses E43 Jessica Wise Inter‐Observer Agreement and Intra‐Observer Repeatability of Two Scoring Systems for Equine Gastric Ulcer Syndrome E45 Camilo Jaramillo Comparison of Blood Gas Analysis, Electrolytes and Plasma Protein Concentrations in Horses at Different Altitudes E46 Kelly Sears Imidocarb Dipropionate Fails to Clear Both Theileria equi and Theileria haneyi in Superinfected Horses E47 Barbara Delvescovo Bile Acids, GGT, and Direct Bilirubin as Prognostic Indicators for Horses with Liver Disease (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) E48 Erin Pinnell Glucose Attenuates AMPK Signaling in the Absence of Insulin in Equine Digital Lamellae E49 Gisela Soboll Hussey FluAvert Stimulates Immunity and Reduces Equine Herpesvirus 1 Replication in Equine Respiratory Epithelial Cells E50 Kathryn Timko Effect of AMPK Agonists on Insulin and Glucose Dynamics in Experimentally‐Induced Insulin Dysregulation in Horses (ACVIM Resident Research Award eligible) E51 Camilo Jaramillo Prevalence of Streptococcus equi in Healthy Horses in Colombia E52 Kathryn Timko Effect of AMPK Agonists on Hepatic AMPK‐Related Gene Expression in Horses with Experimentally‐Induced Insulin Dysregulation (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) E53 Laszlo Hunyadi A Prospective Study of Common Laboratory Variables in Neonatal Foals in Texas E54 Diego Gomez Comparison of Different Methods for Measurement of Electrolytes and Detection of Acid‐Base Disorders in Horses E55 Ilana Glasberg Urinary L‐Lactate Measures in Adult Horses (ACVIM Resident Research Award eligible) E56 Alfredo Sanchez‐Londono Evaluation of Three Different Doses of Thyrotropin Releasing Hormone in Miniature Horses E57 Daniel Jean Prerenal and Renal Failure in Horses: Retrospective Study in an Equine Hospital (1987–2019) E58 Rhonda Hoffman The Thyrotropin‐Releasing Hormone Procedure Produces Repeatable ACTH Concentrations in PPID‐Negative and PPID‐Positive Horses E59 Diego Gomez Methodologic Comparison of Two Analyzers for Measurement of Glucose and Creatinine Concentrations in Sick Horses E60 Julia van Spijk Investigation of Neurological and Nephrogenic Side Effects of Polymyxin B Administration in Healthy Horses (ACVIM Resident Research Award eligible) E61 François‐René Bertin Physiological Changes Associated with Estrous Cycle on Adrenocorticotropic Hormone and Insulin Concentration in Mares E62 Undine Christmann Omega‐3 Fatty Acid Incorporation Into Phosphatidylcholine in Plasma, Synovial Fluid, and Surfactant From Supplemented Horses E63 Rhonda Hoffman Insulin Dysregulation Variables in Equine Metabolic Syndrome are Similar in Horses with previous Non‐Endocrinopathic Founder E64 Hannah Manning Outcome and Survival in 9 Horses Diagnosed with Hematopoietic Neoplasia and Treated with Cytotoxic Chemotherapy (ACVIM Resident Research Award eligible) E65 Melody de Laat Glucose Stimulates GLP‐2 Secretion from Equine Small Intestine E66 Katarzyna Dembek Blood Vitamin C, Vitamin B and Cortisol Concentrations in Healthy and Critically Ill Foals E67 Jaimie Butler The Prevalence of Cyathostomin Anthelmintic Resistance on Horse Farms in Prince Edward Island, Canada (ACVIM Resident Research Award eligible) E68 Steven Grubbs Evaluation of a Clinical Sign Scoring System For Pituitary Pars Intermedia Dysfunction in Horses E69 Edwina Wilkes Efficacy of Single Active and Combination Anthelmintics Against Equine Strongyles in Adult Horses E70 Steven Grubbs Duration of Effectiveness of Frozen/Thawed Thyrotropin Releasing Hormone to Stimulate ACTH Release in Horses E71 Marike Visser Oclacitinib maleate (Apoquel®) Dose Determination in Horses with Naturally Occurring Allergic Dermatitis E72 Alexandra Moss Effect of Oral Trazodone on Intraocular Pressure in Healthy Horses (ACVIM Resident Research Award eligible) E73 Paige Roth Fecal Extract From Obese Horses Induces Inflammation In Vitro E74 Ana Berreta Effect of the Proximal Gastrointestinal Tract on Viability of Equine Probiotics: An in vitro Study (ACVIM Resident Research Award eligible) E75 Christina Marino Pharmacokinetics of Intravenous and Intramuscular Ceftazidime in Neonatal Foals (ACVIM Resident Research Award eligible) E76 Linda Paul Pilot Field Study Comparing the Microbiome in Horses with and without Equine Glandular Gastric Disease (ACVIM Resident Research Award eligible) E77 Wendy Collard Pharmacokinetics of Oclacitinib following Oral and Intravenous Administration to Horses E78 Jenifer Gold Safety of Repeat Gabapentin Dosing (40 or 120 mg/kg) in Adult Horses E79 Natalia Rodriguez Pulmonary Disposition of Gallium Maltolate after Oral Administration to Foals E80 Gayle Hallowell The Value of Transabdominal Ultrasound in Horses Presenting with Medical Gastro‐Intestinal Disease E81 Barbara Delvescovo Effect of Neonatal Dysphagia on Subsequent Racing Performance in Standardbred Horses (ACVIM Resident Research Award eligible) E82 Frank Andrews Effects of Supplements Containing Turmeric and Devil's Claw on Equine Gastric Ulcer Scores in Horses E83 Jane Woodrow Multidimensional Analysis of Bronchoalveolar Lavage Cytokines Reveals Interferon‐Γ as a Key Biomarker in Equine Asthma E84 Laszlo Hunyadi A Retrospective Study of Exercise‐Induced Pulmonary Hemorrhage and Asthma in Barrel Racing Horses in Texas E85 Ann Chapman Clinical Response in Horses with Severe Equine Pasture Asthma to Allergen Specific Immunotherapy FOOD ANIMAL F01 Osman Safa Terzi The Effect of Potassium Levels on Electrocardiographic Data in Calves with Neonatal Diarrhea. F02 Kallie Hobbs Obstipation in Pet Pigs Presented to a University Teaching Hospital: 20 Cases (ACVIM Resident Research Award eligible) F03 Suzanne Clergue Influence of Sample Volume and Time on Rumen Juice Analysis in Cattle (ACVIM Resident Research Award eligible/ACVIM Resident Research Award winner) F04 Lisa Gamsjaeger An Alternative Approach to Evaluating Brix Refractometer Performance for Assessment of Beef Colostrum Quality F05 Kelsey Walker Bacterial Culture and Susceptibility of Samples Taken from Septic Foot Lesions of Adult Beef Cattle (ACVIM Resident Research Award eligible) F06 Toby Pinn‐Woodcock Sudden Death in Weaned Lambs and Calves Due to Strongyloides papillosus in the United States F07 Rachel Oman Urine Acidification Using Oral Methionine in Miniature Pigs F08 Eloi Guarnieri One‐Year Cross‐Sectional Study of Dermatological Lesions in 433 Dairy Cattle in a Veterinary Teaching Hospital (ACVIM Resident Research Award eligible) F09 Abdelmonem Mohamed Arrival Risk Factors Associated with Morbidity in Milk and Grain Fed Veal Calves in Québec F10 Erica Dorsey Clinical and Necropsy Findings Associated with Increased Risk of Natural Death in Critically‐Ill Neonatal Crias F11 Jerry Roberson A Survey of coccidiosis Shedding Among Small Ruminants on St. Kitts and the Appalachian Area F12 Joe Smith Preliminary Investigation of Xenotransfusion as a Therapeutic Modality for Anemia in Goats F13 Alexandra Gariépy Validation of a Predictive Model for Downer Cows Presented to a Hospital F14 Joe Smith Clinical Safety Data for the Use of Pantoprazole in Hospitalized Cattle, a Retrospective Study F15 Alina Hubbuch Change of Antimicrobial Prescriptions in Calves in Switzerland after the Launch of Antimicrobial Use Guidelines F16 Joe Smith Effect of Age and Pregnancy Status on Pharmacokinetics of Flunixin in Dairy Does   ABSTRACT C01 Effects of pimobendan on left atrial transport function in cats with hypertrophic cardiomyopathy Samantha L. Kochie1 ; Karsten Schober1; Jaylyn Rhinehart1; Randolph Winter1; John Bonagura2; Annie Showers1; Vedat Yildiz1 1The Ohio State University; 2North Carolina State University Arterial thromboembolism (ATE) is a sequelae of hypertrophic cardiomyopathy (HCM) in cats related to left atrial (LA) enlargement and dysfunction. This study addresses the general hypothesis that pimobendan, an inodilator, improves LA transport function in healthy cats and cats with HCM. Prospective, double‐blind, randomized, placebo‐controlled clinical cohort study. 21 cats with HCM and 10 healthy control cats underwent two examinations 4–7 days apart. Cats were randomized to receive either pimobendan (0.25 mg/kg body weight q 12 h) or placebo. Two‐dimensional and Doppler echocardiographic variables of LA function (LA shortening fraction and fractional area change, velocities of A, AR, and A′ waves, LA ejection force, LA kinetic energy, and peak left auricular flow velocity) were evaluated. Data were statistically compared using standard test procedures for before–after comparisons and linear mixed model analysis. Several echocardiographic variables characterizing LA size and function were increased after pimobendan: Left auricular flow velocity (0.85 ± 0.20 m/s vs. 0.71 ± 0.22 m/s, p = 0.009), estimated total LA volume (p = 0.030), LA emptying area (p = 0.036) and LA emptying volume (p = 0.032), and A velocity (0.77 ± 0.12 vs. 0.62 ± 0.17, p = 0.049). LA kinetic energy (p = 0.19) and LA ejection force (p = 0.27) were not different after pimobendan. Status (HCM vs. healthy) and LA size (normal vs. increased) were not identified as independent predictors of drug effect in the multivariate model. This study identified positive, albeit minor, effects of pimobendan on LA reservoir and pump function in cats with pre‐clinical HCM. Whether or not chronic therapy with pimobendan can reduce the risk of cardiogenic embolism deserves further study. ABSTRACT C02 Canine oblique angiographic projections in dorsal, left lateral, and right lateral recumbency Caroline Q. Sloan; Brian Scansen; Kursten Pierce; I‐Jung Chi; Christopher Orton Colorado State University In humans, oblique angiographic projections help optimize cardiac interventions and assume dorsal recumbency. Interventions in animals are performed in both dorsal and lateral recumbency without standardized veterinary terminology. The study aim was to develop and evaluate an angiographic nomenclature for oblique fluoroscopic projections in dogs that is consistent regardless of patient recumbency. Twelve canine cadavers underwent left (n = 6) and right (n = 6) heart catheterization. Cardiac structures were opacified with iodinated contrast. Oblique projections were acquired every 30 degrees across 180 degrees of detector arc. Projections were obtained in variable recumbency (dorsal, left lateral, right lateral) for each dog with staggered sequence order. A rotational angiogram was then acquired, allowing reconstruction of all projection angles. Evaluators were blinded to patient positioning and a scoring system was used to evaluate similarity of each projection obtained in different states of recumbency. Angiographic projections were labeled according to beam‐to‐detector path relative to the dog, regardless of C‐arm or table position. For example, a 30 degree right ventral oblique projection was defined as the detector angled 30 degrees from sternum toward the dog's right shoulder. Contrast was gravitationally dependent resulting in subjective differences in chamber opacity between recumbent states. All projections were graded as equivalent irrespective of recumbency. We propose a unified terminology for canine angiography that can be applied to oblique projections and is agnostic to patient recumbency and C‐arm position. This nomenclature may improve consistency in future studies and as structural heart interventions begin to adopt unique angulations to guide transcatheter therapies in animals. ABSTRACT C03 Effect of pimobendan on cardiac and renal function in canine subclinical myxomatous mitral valve disease Joanna L. Kaplan; Lance Visser; Catherine Gunther‐Harrington; Eric Ontiveros; Luke Wittenburg; Carrie Palm; Joshua Stern University of California, Davis We sought to determine the effects of standard‐dose and high‐dose pimobendan on cardiac size and function and renal function estimates in dogs with subclinical myxomatous mitral valve disease (MMVD). Dogs <15 kg diagnosed with stage B2 MMVD were enrolled in this prospective, randomized, blinded, placebo‐controlled, clinical trial. Azotemic dogs and dogs taking cardiac medications were excluded. N‐terminal pro‐brain natriuretic peptide (NT‐proBNP), quality‐of‐life (QOL) scoring, renal function (iohexol clearance ELISA‐estimated glomerular filtration rate, symmetric dimethylarginine, and creatinine concentration), and echocardiographic cardiac size and function were evaluated before and 7–10 days after placebo (n = 6), standard‐dose pimobendan 0.2–0.3 mg/kg q 12 (SD_pimo; n = 12), or high‐dose pimobendan 0.5–0.6 mg/kg q 12 h (HD_pimo; n = 12). Paired t‐tests (or nonparametric equivalent) were used for comparisons within group. ANOVAs and Tukey's post‐hoc tests (or nonparametric equivalent) were used for comparisons among groups. There were no significant differences in renal function indices within the placebo, SD_pimo, and HD_pimo groups (p ≥ 0.13). There were no significant differences (p ≥ 0.48) of QOL scores within the placebo, SD_pimo, and HD_pimo groups. Significant differences (p < 0.001) in percent change of NT‐proBNP were identified among the placebo (0.7%), SD_pimo (−36.7%), and HD_pimo (−46.0%) groups. Echocardiographic data are presented in Table 1. Results suggest pimobendan possesses a dose‐dependent benefit on cardiac function but does not significantly affect (increase or decrease) QOL or tests that estimate renal function in dogs with subclinical MMVD. Further study of the dose‐dependent effects of pimobendan is warranted, particularly in dogs with MMVD and renal dysfunction, heart failure, or both. Table 1. Mean (SD) of echocardiographic variables before and 7–10 days after placebo, standard‐dose pimobendan (SD_pimo, 0.2–0.3 mg/kg PO q 12 h), and high‐dose pimobendan (HD_pimo, 0.5–0.6 mg/kg PO q 12 h) in dogs with subclinical myxomatous mitral valve disease Variables Group Before After p‐value (Before vs After) % change p‐value (% change among groups) LAV (mL/kg) Placebo 3.0 (1.0) 3.1 (1.2) 0.68 1.3 (15.6) 0.004 SD_pimo 2.8 (0.8) 2.1 (0.6) 0.002 −22.7 (14.9)a HD_pimo 3.3 (1.4) 2.4 (1.1) <0.001 −27.1 (16.9)a LVVd (mL/kg) Placebo 4.0 (1.1) 3.9 (0.8) 0.1 −0.2 (8.2) 0.009 SD_pimo 3.8 (0.7) 3.2 (0.7) <0.001 −16.7 (12.5)a HD_pimo 3.7 (0.8) 2.9 (0.8) 0.001 −21.8 (15.0)a LVVs (mL/kg) Placebo 0.86 (0.32) 0.77 (0.29) 0.47 −7.3 (35.6) <0.001 SD_pimo 0.99 (0.41) 0.57 (0.28) <0.001 −41.6 (14.8)a HD_pimo 1.06 (0.30) 0.48 (0.29) <0.001 −55.0 (20.7)a LV EF (%) Placebo 78.5 (4.3) 80.3 (6.7) 0.49 2.3 (7.3) 0.007 SD_pimo 74.4 (7.2) 82.5 (5.4) <0.001 11.3 (7.8) HD_pimo 71.3 (8.3) 83.5 (8.9) <0.001 17.6 (10.4)a LAV, left atrial volume; LVVd, left ventricular volume at end‐diastole; LVVs, left ventricular volume at end‐systole; LV EF, left ventricular ejection fraction; SD_pimo, standard‐dose pimobendan; HD_pimo, high‐dose pimobendan. aSignificantly different (p<0.05) compared to percent change of the placebo group. Significant differences are in bold typeface.   1 2 3 ABSTRACT C04 Complications and outcomes associated with epicardial pacemakers in cats Eva W. Frantz; Sonja Tjostheim; Alexandra Palumbo; Heidi Kellihan; Rebecca Stepien School of Veterinary Medicine, University of Wisconsin Epicardial pacemaker implantation is the treatment of choice for cats with clinical signs secondary to bradyarrhythmias. Complication rates and long‐term outcomes, however, have only been reported in a small number of cats. The objectives of this study were to describe the major and minor complications in a larger population of cats (n = 20) that received epicardial pacemakers and to report their survival rates. Medical records (2003–2019) were reviewed. Presenting complaint, indication for pacing, presence of structural heart disease, presence of congestive heart failure, presence of a major or minor complication, and survival time were recorded and assessed in the statistical analysis. A complication was determined to be major if it was life‐threatening or required replacement of the pacemaker system, while minor complications were not life‐threatening and generally self‐limiting or required minimal intervention. None of the variables evaluated were associated with a significant increase in the incidence of major or minor complications. The most common major complication was loss of ventricular capture (n = 6), which was successfully treated in all cases by increasing pacemaker output and/or replacing the pacemaker lead. Lead dislodgement, the most common major complication reported previously in dogs with epicardial pacemakers, was not documented in this population of cats. The overall survival time (MST 948 days) was similar to that previously reported in dogs with epicardial pacemakers (Figure 1). Fifty percent of cats had one or more major complication, which is comparable to major complication rates previously documented in cats. No statistical difference in survival time was identified between cats that experienced a major complication and those that did not (p = 0.773; Figure 2). This study provides relevant insights into the complications and outcomes of epicardial pacemakers in cats. Major complications were not associated with reduced survival time in this population.   ABSTRACT C05 The use of activity response settings in rate responsive pacemakers in dogs: A retrospective study Ananda Pires 1; Michelle Colpitts1; Shari Raheb1; Lynne O'Sullivan2; Sonja Fonfara1 1University of Guelph; 2University of Prince Edward Island Third degree atrioventricular block (3rdAVB) is a common bradyarrhythmia in dogs for which pacemaker implantation is the gold‐standard treatment. Pacemakers with rate responsive mode (VVIR) capability are usually implanted, as these provide the option of heart rate adjustment in response to activity. The aim of the present study was to determine the efficacy of the rate responsive setting of VVIR pacemakers in dogs that have pacemakers for 3rdAVB. Medical records of the Ontario Veterinary College were retrospectively searched and a total of 28 dogs with VVIR pacemakers for 3rdAVB were identified. Pacemaker interrogations, 6–12 months after placement, detected that the dogs spent the most time at the programmed lower rate with only minor heart rate variation. In 9/28 (32%) dogs, the activity daily living (ADL) and exertion responses were increased one or two levels to improve pacemaker response to activity. In 5/9 (55%) dogs, this did not elicit heart rate variation; in one dog this resulted in heart rate variation (this dog had an epicardial lead with abdominal generator, contrary to the other dogs); 3/9 (33%) dogs died before re‐evaluation. In the majority of dogs with VVIR pacemakers for 3rdAVB, the default rate responsive mode did not result in heart rate variation. An increase of the activity response settings did not improve pacemaker response to activity, and it is possible that further adjustments are required. Furthermore, positioning of the pacemaker generator might influence rate responsiveness of a VVIR pacemaker. ABSTRACT C06 Use of omics technologies in the investigation of diet‐associated dilated cardiomyopathy (DCM) in dogs Lisa M. Freeman 1; Caren Smith2; John Rush1 1Cummings School of Veterinary Medicine, Tufts University; 2Human Nutrition Research Center on Aging, Tufts University The objective of this study was to use metabolomic and lipidomic data from diets and dogs to identify possible dietary factors associated with canine diet‐associated DCM. Eighteen diets (9 non‐traditional and 9 traditional) were analyzed in duplicate using metabolomic and lipidomic platforms (i.e., foodomics) at a commercial laboratory. Metabolomic analysis was also performed on 20 canine plasma samples: Dogs with DCM and congestive heart failure (CHF) eating traditional diets (n = 5), dogs with DCM and CHF eating non‐traditional diets (n = 5), dogs with DCM but no CHF eating non‐traditional diets (n = 5), and healthy control dogs eating traditional diets (n = 5). Samples were analyzed using Ultrahigh Performance Liquid Chromatography‐Tandem Mass Spectroscopy. Of 830 biochemicals identified in the metabolomics profile of the dog foods, 261 were significantly increased and 153 were significantly decreased in non‐traditional vs. traditional diets associated with multiple metabolic pathways. Of 966 biochemicals in the dietary lipidomic profile, 140 were significantly increased and 277 were significantly decreased in non‐traditional vs. traditional diets. A number of metabolites distinguished the 2 diet groups including 3 unnamed biochemicals that were identified in 100% of non‐traditional diets and 0% of traditional diets, but none of the 3 biochemicals was found in the plasma of affected dogs. Plasma metabolomic profiles identified multiple significant differences between dogs with CHF eating non‐traditional vs. traditional diets. Omics technologies, such as metabolomics, can provide functional information on both individual diet constituents and blood biochemicals that may assist in drawing mechanistic connections between diet and complex, multifactorial diseases, such as diet‐associated DCM. ABSTRACT C07 Evaluation of myocardial fibrosis in cats with hypertrophic cardiomyopathy using cardiac magnetic resonance imaging Ryan Fries; Saki Kadotani; Stephanie Keating; David Schaeffer; Jonathan Stack College of Veterinary Medicine, University of Illinois at Urbana–Champaign Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. Echocardiography is the non‐invasive reference standard for diagnosing HCM; however, it has little to no value in assessing myocardial composition. Recent advances in cardiac magnetic resonance imaging (CMR) have allowed for detection of diffuse and focal fibrosis in a variety of heart conditions, including HCM. The objective of this study was to quantify myocardial fibrosis, namely T1 mapping and extracellular volume fraction (ECV) in healthy and HCM cats using CMR. Seventeen healthy and twelve HCM, age‐matched, client‐owned cats were prospectively enrolled. Tests performed included physical examination, indirect blood pressure, complete blood count, biochemical analysis including total thyroid, urinalysis, transthoracic echocardiogram, and CMR with contrast. Cats were considered healthy if all diagnostic tests were within normal limits and a diagnosis of HCM was determined by the presence of either focal or generalized left ventricular concentric hypertrophy >6 mm on echocardiography. Between groups, there were no statistical differences in regard to age, indirect blood pressure, or laboratory results. Statistically significant CMR parameters included left ventricular mass (healthy = 5.87 g, HCM = 10.3 g, p < 0.0001), T1 native mapping (healthy = 1122 ms, HCM = 1209 ms, p = 0.004), and ECV (healthy = 26.0%, HCM = 32.6%, p < 0.0001). Results of this study confirm that CMR is useful at detecting myocardial fibrosis in cats with HCM and that myocardial composition is different between normal and HCM cats. ABSTRACT C08 Renin‐angiotensin‐aldosterone system activation in hypertensive cats receiving amlodipine Clarke E. Atkins 1; Darcy Adin2; Catherine Glahn3; Oliver Domenig4; Teresa DeFrancesco1 ; Kate Meurs1 1North Carolina State University; 2University of Florida; 3Coastal Cat Clinic; 4Attoquant Diagnostics Chronic Renin‐Angiotensin‐Aldosterone‐System (RAAS) activation is harmful. Vasodilators, including amlodipine in man and the dog, activate RAAS. Contradictory data exist, however, for the hypertensive cat. We sought to clarify this, with a novel method of global circulating RAAS analysis. We hypothesized that naturally hypertensive cats, receiving chronic amlodipine therapy experience RAAS activation, as compared to normal, untreated subjects. We enrolled 9 client‐owned, unmedicated, normotensive cats, normal by physical examination, basic laboratory tests, and echocardiography and 5 client‐owned cats, with proven hypertension, IRIS Stage 2–3 chronic kidney disease (2 also hyperthyroid, 1 diabetic), receiving amlodipine chronically (average 1.5 years). Average systolic blood pressure was 166 mm Hg, down from an average maximum of 188.6 mm Hg. None received RAAS‐suppressant therapy. Serum was frozen (−80C) for future blinded LC‐MS/MS‐based RAAS equilibrium analysis quantification/calculation of RAAS components and select RAAS enzymes. Analytes, reported as mean (± SD) and median (25th–75th quartiles), were compared between groups, using non‐paired student's t‐test. RAAS activation was significantly greater in hypertensive cats receiving amlodipine, as compared to normal cats. Significant elevations in hypertensive cats were observed for values of Renin, Angiotensin I, Angiotensin 1‐7, Angiotensin III, and Angiotensin 1‐5, and Aldosterone. Mean angiotensin converting‐enzyme activity was less in hypertensives (p < 0.05), while chymase activity was 50% greater (p > 0.05). While RAAS is chronically activated in hypertensive cats receiving amlodipine, the exact role played by amlodipine is not clarified by this study. Nevertheless, the data indicate that concurrent RAAS‐suppressant therapy is indicated in hypertensive cats with hyperthyroidism and/or chronic kidney disease, receiving amlodipine. ABSTRACT C09 Prevalence of the PDK4 and titin gene mutations in North American Doberman Pinschers Ryan Fries 1; Nancy Morris2; Amara Estrada3; Kathryn Meurs4 1College of Veterinary Medicine, University of Illinois at Urbana–Champaign; 2Veterinary Emergency and Specialty Hospital; 3University of Florida; 4North Carolina State University Dilated cardiomyopathy (DCM) is the most common cardiomyopathy in dogs and in Doberman Pinschers (DP), the estimated lifetime risk is 25–50%. In DP of North America, two genetic mutations are reportedly associated with developing DCM. One encoding for the pyruvate dehydrogenase kinase 4 (PDK4) gene and one encoding for the titin gene. The objective of our prospective, longitudinal cohort study is to determine the prevalence of these two mutations in a population of North American DP and evaluate the influence of these mutations on the development of DCM in this population. All dogs are screened annually including physical examination, echocardiogram, Holter monitor, and client questionnaire. Diagnosis of DCM is based on criteria from the European Society of Veterinary Cardiology screening guidelines. A total of 385 dogs are currently enrolled. Regarding the PDK4 mutation, 52.3% are negative, 38.1% are heterozygous positive, and 9.6% are homozygous positive. Regarding the titin mutation, 20.6% are negative, 51.1% are heterozygous positive, and 28.3% are homozygous positive. Only 13.1% are negative for both mutations. At the time of initial screening, 73.4% of DP had a normal echocardiogram, 15.9% had occult DCM, 6.9% were considered equivocal, and 3.1% were diagnosed with myxomatous mitral valve disease. In the occult DCM subset, 89.1% of dogs had at least one mutation. With an incidence of at least one mutation in 86.9% of DP in this population, ongoing screening and outcome analysis is essential for understanding the influence of these genetic mutations on the development of DCM in DP. ABSTRACT C10 Diagnostic utility of caudal vena cava measurements in dogs with cavitary effusions or heart failure Yen Yu Chou 1; Jessica Ward2; Lara Barron3; Melissa Tropf2; Shane Murphy2; Gregory Lisciandro4; John Bonagura3; Anna McManamey3 ; Teresa DeFrancesco3 1Iowa State University; 2College of Veterinary Medicine, Iowa State University; 3College of Veterinary Medicine, North Carolina State University; 4Hill Country Veterinary Specialists Thoracic ultrasound has proven effective for the diagnosis of left‐sided congestive heart failure (L‐CHF) dogs and cats with respiratory distress. The objective of this study was to determine whether ultrasonographic indices of the caudal vena cava (CVC) could be used to diagnose right‐sided CHF (R‐CHF) in dogs with cavitary effusions. Dogs were prospectively enrolled in four groups: R‐CHF (n = 34), L‐CHF (39), cavitary effusions of noncardiac etiology (NC, 41), and pericardial effusion with tamponade (PCEFF, 17). Ultrasonographic indices included right ventricular to left ventricular ratio (RV:LV) and 2D and M‐mode subxiphoid measures of CVC maximal and minimal size (CVCmax and CVCmin), CVCmax indexed to aortic dimension (CVC:Ao), and CVC collapsibility index (CVC‐CI). Variables were compared between study groups using Kruskal‐Wallis and Dunn's‐Bonferroni testing. All indices (RV:LV, CVCmax, CVCmin, CVC:Ao, and CVC‐CI) were significantly different between R‐CHF and NC dogs (p < 0.005). A CVC‐CI less than 30% (in either M‐mode or 2D) was 97% sensitive and 93% specific for diagnosis of R‐CHF versus NC effusion. All CVC indices, but not RV:LV ratio, also differed between PCEFF and NC dogs (p < 0.005). Compared to NC, L‐CHF dogs had higher CVC:Ao in both 2D (p = 0.017) and M‐mode (p = 0.014); compared to R‐CHF, L‐CHF dogs had higher CVC‐CI in both 2D and M‐mode (p < 0.005). Ultrasonographic indices of CVC size and collapsibility are useful to differentiate R‐CHF versus NC disease as causes of cavitary effusions. Dogs with L‐CHF demonstrate CVC measurements intermediate between R‐CHF and NC dogs. ABSTRACT C11 Tricuspid valve dysplasia is associated with a PLA2G4F variant in the Labrador Retriever Kathryn Meurs 1; Sandy Tou2; Teresa DeFrancesco1 ; Bruce Keene1; John Bonagura1; Steven Friedenberg3 1North Carolina State University; 2College of Veterinary Medicine, North Carolina State University; 3University of Minnesota Tricuspid valve dysplasia (TVD) is a congenital heart defect observed most commonly in the Labrador Retriever. Some dogs have only a mild form of the defect and can live comfortably, often with no outward signs, while others have significant valvular insufficiency and congestive heart failure. TVD has been shown to be a heritable trait in the Labrador Retriever. We hypothesized that we could identify a genetic marker for the trait in the Labrador Retriever by performing Whole Genome Sequencing with affected Labrador Retrievers and filtering them against 478 unaffected non‐Labrador Retriever dogs. We identified a variant in a candidate gene, PLA2G4F (phospholipase A2 group IVF) that contains a malignant variant that changes a conserved amino acid from glutamic acid to aspartic acid. The variant is strongly associated with TVD (p = 0.0001) and was found in 63 of 64 affected Labrador Retrievers and was not in 12 echocardiographically confirmed unaffected Labrador Retrievers. It was also identified in 2% of the general canine population of 478 non‐Labrador Retriever dogs and 56 of 70 Labrador Retrievers of unconfirmed phenotype. These findings are suggestive of incomplete penetrance of the variant. In silico predictions suggest that this variant could change the protein structure of PLA2G4F. PLA2G4F is responsible for facilitating the breakdown of phospholipase to arachidonic acid and is ultimately involved in the development of prostaglandins thought to play a role in heart disease and cardiac development. We conclude that PLA2G4F may be associated with the development of tricuspid valve dysplasia in the Labrador Retriever. ABSTRACT C12 Evaluation of galectin‐3 as a novel biomarker in feline hypertrophic cardiomyopathy Jonathan Stack; Ryan Fries; Saki Kadotani; Leah Kruckman; Gabrielle Wallace College of Veterinary Medicine, University of Illinois at Urbana–Champaign Galectin‐3, a circulating biomarker, correlates with myocardial fibrosis in humans. It independently predicts mortality and adverse outcomes in cardiovascular disease, including hypertrophic cardiomyopathy (HCM). In veterinary medicine, risk‐stratification of feline HCM patients is difficult and largely based on specific echocardiographic findings such as left atrial enlargement. The purpose of this study was to evaluate galectin‐3 as a potential clinical biomarker in feline HCM. Thirty healthy cats, nineteen cats with occult HCM (left ventricular concentric hypertrophy >6 mm), and twenty‐six cats with HCM and past or present congestive heart failure (CHF) were enrolled. Tests performed included echocardiography, complete blood count, serum chemistry, total T4, thoracic radiographs, and blood pressure to categorize each cat and ensure no concurrent diseases. When possible, quantitative NT‐proBNP levels, cardiac troponin I levels, and urinalysis were performed. Serum galectin‐3 levels were determined using a validated, commercially available colorimetric quantitative ELISA. Galectin‐3 was significantly elevated in all cats with HCM compared to healthy cats (p < 0.009). Subgroup analysis found galectin‐3 was significantly elevated in CHF compared to healthy cats (p = 0.0140), but was not significantly different between healthy and occult HCM cats (p = 0.1094) or between occult and CHF cats (p = 0.8318). Cats with a history of CHF had significantly higher levels of blood urea nitrogen and creatinine, and lower levels of potassium and chloride compared with all other groups. Results of this study confirm that galectin‐3 is increased in cats with HCM and warrants further investigation as a clinical biomarker. ABSTRACT C13 Use of three‐dimensional models of echocardiographic imaging planes in the teaching of echocardiography Marlos Gonçalves Sousa; Bruna Costa; Marcela Wolf; Simone Stedile Federal University of Paraná Heart disease in dogs and cats has a high incidence in clinical routine, with echocardiography being the most used test for its diagnosis. The main difficulty presented by beginners in echocardiography is the orientation of the echocardiographic imaging plane with the three‐dimensional (3D) anatomy of the heart. As 3D models are advantageous in understanding two‐dimensional images, the hypothesis of this study is that 3D echocardiographic models would be useful in teaching echocardiography. Thus, the objective of this work was to develop and test 3D models of healthy and sick hearts of dogs and cats, to evaluate its effectiveness in undergraduate vet students understanding echocardiographic imaging planes. Model hearts made out resin with the main normal echocardiographic imaging planes of dogs and cats were produced, as well as models with mitral endocardiosis in dogs and hypertrophic cardiomyopathy in cats. Students from the 4th year of the Veterinary Medicine degree were invited to participate, and after a theoretical class they were randomly assigned to two groups, the model group and the control group. The model group had access to 3D models, along with a self‐explanatory text on echocardiographic imaging planes, and the control group had access only to the self‐explanatory text. Both groups had two weeks to study. The students answered a quiz to evaluate their learning, and also answered an anonymous questionnaire to give their opinion about the experience with the learning method used. A total of 39 students participated in the study, 19 of them in the model group and 20 in the control group. The dedicated study time was longer in the model group (p = 0.0027); being that 7 of these students (36.8%) exceeded 2 hours of study. The proportion of students who achieved a satisfactory grade in the quiz was 89.5% in the model group and 60% in the control group (p = 0.0449). Students with no previous experience who studied on the model were better at the quiz when compared to students in the control group who also had no previous experience (p = 0.0516). The present study shows that the three‐dimensional models of echocardiographic imaging planes of dogs and cats facilitated and significantly improved learning and the identification of cardiac structures and abnormalities, and provided greater motivation for students through the study of echocardiography. ABSTRACT C14 Clinical relevance of serum electrolytes in small animals with acute heart failure: A retrospective study Marine Roche‐Catholy 1 ; Iris Van Cappellen2; Laurent Locquet2; Bart Broecks2; Dominique Paepe2; Pascale Smets2 1Faculty of Veterinary Medicine, Ghent University; 2Ghent University Electrolyte abnormalities frequently occur in congestive heart failure (CHF) patients. Hypochloremia has been identified as a marker of diuretic response and as a strong negative prognostic factor in people with CHF. However, publications on prognostic implications of electrolyte abnormalities in small animals with CHF are lacking. We aimed to document electrolyte abnormalities upon admission of dogs and cats with acute CHF, and to evaluate the associations between electrolyte concentrations and diuretic dose, and between electrolyte concentrations and prognostic variables. Dogs and cats with first onset of acute CHF, confirmed by medical imaging, and a complete electrolyte panel performed upon admission were retrospectively included. A total of 46 dogs and 34 cats met the inclusion criteria. The most commonly encountered electrolyte anomaly was hypochloremia observed in 24% (9/46 dogs and 10/34 cats) of cases. In dogs only, a significant negative correlation was identified between serum chloride levels at admission and furosemide doses both at discharge and at end‐stage heart failure (r = −0.59; p < 0.001 and r = −0.62; p = 0.004 respectively). With regard to prognostic variables, no significant hazard ratios were found for duration of hospitalization nor survival time for any of the electrolyte concentrations. The present study provides new information supporting hypochloremia as a potential marker of impaired diuretic response in dogs presented with a first episode of acute CHF. Further prospective studies are needed to clarify the relationship between hypochloremia and diuretic response in dogs and cats with acute CHF, and its long‐term implications. ABSTRACT C15 Rapid arteriotomy site closure using preplaced purse‐string suture technique in dogs Kursten V. Pierce; Brian Scansen; E. Christopher Orton Colorado State University Ligation following arterial catheterization after image‐guided interventions is common practice in veterinary medicine, which may affect vascular supply or limit future access. This prospective case series investigated the utility of a preplaced purse‐string suture technique for rapid closure of arterial catheterization sites in dogs. An arterial cutdown was performed and a purse‐string suture either in a square or diamond‐shaped pattern was preplaced around the intended arterial puncture site using 6‐0 monofilament, nonabsorbable polypropylene suture in 8 dogs with a median body weight of 15.5 kg (range, 4.3 to 32 kg) undergoing femoral (n = 7) and carotid (n = 1) arterial catheterization. Within the loose preplaced suture, arterial puncture was performed with an over‐the‐needle catheter and an introducer sheath was placed. When the procedure was finished, the introducer sheath was removed while the preplaced suture was tightened to achieve hemostasis at the arteriotomy site. Catheterizations included ductal occlusion (n = 3), diagnostic left heart catheterization (3), transarterial chemoembolization of hepatocellular carcinoma (1), and stent graft implantation for aortoiliac thrombosis (1). Complete hemostasis was achieved in 2 dogs at time of purse‐string closure, mild bleeding occurred in 4 dogs with complete hemostasis after placement of an addition single inverting stich, and the suture tore through the vessel wall in 2 dogs during tightening of the purse‐string leading to ligation. Human suture‐mediated vascular closure devices provided the basis for this direct suture technique, which appears to be a low‐cost, viable option to avoid ligation during arterial catheterization in dogs. Success appears dependent on operator experience and surgical skill. ABSTRACT C16 Correlation of hepatic venous doppler with right ventricular morphofunctional parameters in dogs with pulmonary hypertension Marlos Gonçalves Sousa; Vinícius Silva; Tilde Froes; Stephany Lucina; Marcela Wolf Federal University of Paraná The aims of this study were three‐fold: to investigate, prospectively, the reliability of the hepatic vein Doppler waveform to diagnose and characterize the magnitude of pulmonary hypertension in dogs; to evaluate whether a correlation exists between hepatic venous flow waves and the structural and functional characteristics of the right ventricle; and to determine whether age, gender, body weight, heart rate, heart rhythm and systolic blood pressure play a role in the hepatic venous waveform pattern. The cross‐sectional observational study included 43 dogs with varying degrees of pulmonary hypertension and a control group composed of 15 healthy dogs. From the pulsed spectrum of the hepatic veins, the direction and velocity of each of the four components was established. The wave forms were classified into three different patterns: type 1, type 2, and type 3 (Figure 1). The velocities of the hepatic A, S, V and D spectral waves and the phasic pattern varied according to the severity of pulmonary hypertension (Table 1). The pattern of hepatic veins waveforms varied in patients with pulmonary hypertension as compared to control dogs (p < 0.05). There were no differences between the results obtained in males and females. In mild pulmonary hypertension, 8 dogs showed pattern 1 and 9 dogs, pattern 2. For moderate pulmonary hypertension, the majority of the dogs (n = 15) had pattern 2, while only 2 dogs showed pattern 1. In animals with severe pulmonary hypertension, there was a substantial qualitative change in the documented pattern: 7 dogs had pattern 3 whereas the other 2 showed pattern 2. Correlation were documented between hepatic vein waves and age, heart rate and the right ventricle structural and functional variables. Wave D had a sensitivity of 100% when a cut‐off of 11.6 cm s−1 was used to differentiate dogs with pulmonary hypertension from healthy dogs. The hepatic flow pattern was most affected in patients with moderate and severe pulmonary hypertension. This study shows the feasibility of this methodology as a supplementary technique for the recognition and staging of pulmonary hypertension. Also, Doppler hepatic venous flow was correlated with parameters that describe right ventricle function and structure.   ABSTRACT C17 Ultrasonographic assessment of canine femoral vessels: Relationship to age, body size, sex, and conformational measurements Katrina Cusack; Sonya Wesselowski; Ashley Saunders; Nicholas Jeffery Texas A&M University Minimally invasive transvascular procedures have advanced in veterinary medicine, but basic knowledge about expected vascular size and vascular imaging requires further exploration. Ultrasonographic imaging of the femoral artery (FA) and vein (FV) in a large population of dogs to describe relationships between vessel diameter and various patient characteristics. Animals were 230 client‐owned dogs. Body measurements were obtained: body weight, withers height, body length, thigh circumference, head length and head width. A linear ultrasound probe was used to measure the internal diameter of the FA and FV bilaterally. Measurement repeatability was assessed. Allometrically scaled body weight had the strongest correlation with diameter of the FA and FV (correlation coefficients: 0.92, 0.80, respectively), although thigh circumference (FA:0.89, FV:0.78) and withers height (FA:0.84, FV:0.76) were also strongly correlated. Within the entire population, males had a smaller FA (p = 0.005), but not FV (p = 0.278), than females and age was negatively associated with FA (p = 0.031) and FV (p ≤ 0.001) diameter. Comparison of left and right FA and FV diameter revealed minimal mean differences, though limits of agreement could encompass multiple French gauge sizes: [Mean difference (limits of agreement): FA = 0 mm (0.85 to 0.84 mm), FV = 0.035 mm (1.92 to 1.99 mm)]. Coefficients of variation for intra and interoperator repeatability were <9%. The diameter of the canine FA and FV is influenced by multiple factors, with potential for clinically relevant differences between right and left‐sided vessels. Ultrasound measurement of the FA and FV was fast, repeatable, and could improve pre‐procedural planning. ABSTRACT C18 Presence of gut dysbiosis in dogs with heart failure: A pilot study Joonbum Seo; Linda Matthewman; Dong Xia; Yu‐Mei Chang; Jenny Wilshaw; David Connolly Royal Veterinary College, University of London The contribution of gut microbiota in the development and maintenance of heart failure known as the “gut hypothesis” describes impaired gut health in heart failure patients, resulting in dysbiosis and bacterial translocations across the edematous mucosal layer. This results in immune‐stimulation via endotoxins, contributing to a chronic inflammatory state, malnutrition and cachexia. While this has been the focus of evaluation of novel therapies in people with advanced heart failure, no such research has been described in veterinary medicine. We hypothesized that dogs in congestive heart failure (CHF) have quantifiable alterations in gut microbiota compared to healthy control dogs. This is a cross‐sectional pilot study. Pre‐study power calculation showed 15 dogs were required in each group. Fecal samples were collected from healthy dogs and dogs affected by left CHF or right CHF. Fecal DNA was extracted, and the samples were transported to an external molecular Lab (Mr DNA, Texas, USA) for 16S rRNA sequencing (Illumina®). QIIME2 pipeline was used to analyze the microbial communities, and R, SPSS and Galaxy (Huttenhower Lab, harvard.edu) were used for statistical analysis. A total of 15 healthy dogs, 16 left CHF dogs, and 15 right CHF dogs were enrolled. Results showed no difference in alpha‐ (p = 0.68) and beta‐diversity (p = 0.33) among the control, left CHF and right CHF groups. However, taxa analysis showed an increase in abundance of the Proteobacteria line in dogs with CHF (p = 0.01). In conclusion, our pilot study demonstrated an alteration in the gut microbial communities in dogs with CHF without a change in the overall biodiversity and richness. The gut health is likely compromised in dogs with CHF. ABSTRACT C19 Combination radiation therapy and chemotherapy for right atrial masses with pericardial effusion in dogs Kimberly N. Cook; Thaibinh Nguyenba; Ioannis Giatis; Heather Lasher; Lisa Fulton; Deborah Prescott MedVet Medical and Cancer Center for Pets Pericardial effusion (PE) secondary to right atrial (RA) masses in dogs carries a poor long‐term prognosis with limited treatment options. Our objective was to assess combination radiation and chemotherapy outcome in dogs with PE and RA masses. Medical records between January 2010 and June 2019 were reviewed retrospectively to identify treatment group dogs diagnosed with PE and RA masses via echocardiography that received both radiation and chemotherapy. A retrospective disease matched control group without radiation and chemotherapy was also sought. Data collected included presenting temperature, heart rate, blood pressure, ascites, arrhythmias, need for pericardiocentesis, and metastasis along with time to initial radiation treatment, radiation protocol, chemotherapy protocol, survival time, and cause of death. Eighteen treatment group and 22 control group dogs were identified. Treatment group median survival time was 124.5 days (range 4–358 days), and survival was unaffected by chemotherapy protocol or presenting heart rate, temperature, blood pressure, ascites, arrhythmias, pericardiocentesis, or metastasis. Control group median survival time following pericardiocentesis was 7.5 days (range 1–77 days). For survival comparison, dogs that received radiation after 6 days (mean time to initial radiation treatment) and control dogs that died before 6 days were excluded. Baseline characteristics were similar between groups. Treatment group survival was longer than the control group (p < 0.01). Radiation and chemotherapy were tolerated. This study suggests combination radiation and chemotherapy is viable and extends survival time in dogs with PE secondary to RA masses, compared to control dogs. Further research is needed to determine independent effects of radiation therapy. ABSTRACT C20 Effect of multi‐dose oral trazodone on arterial blood pressure in normal beagles Sienna R. Drizin; Kathryn Wotman; Kyle Kline; Michael Lappin; Rebecca Ruch Gallie Colorado State University Trazodone is prescribed by veterinarians for reducing stress in hospitalized dogs, treating behavioral disorders, and facilitating confinement in post‐surgery recovery. However, there are unknowns about how this drug affects canine physiology and no studies have evaluated the peripheral cardiovascular effects of multi‐dose oral trazodone in awake patients. The objective of this randomized double‐blinded crossover study was to evaluate the effect of multi‐dose oral trazodone on blood pressure in normal dogs. Eight research beagles were randomly assigned to treatment and control groups, then switched after a 3‐day washout. Control groups received placebo and treatment groups received 50 mg of trazodone orally once per day. Systolic blood pressure was measured via Doppler prior to and at 1, 4, 8 and 12 hours post‐treatment for a total of three days. A sedation score was recorded for each dog at every time‐point. A mixed model was fit to the data, and Dunnett's method was used to compare downstream time points versus baseline for each treatment. Wilcoxon signed‐rank test was used to compare sedation scores between treatments at each time point. Average blood pressure in the treated dogs compared to the untreated dogs did not change significantly throughout the measurement period. Sedation scores did not significantly change between the treated and untreated groups apart from T1 on day 1 (p = 0.031). Based on the findings of this study, oral administration of clinically useful doses of trazodone in healthy dogs does not cause a significant change in systolic blood pressure. ABSTRACT C21 Prevalence of the angiotensin‐converting enzyme gene polymorphism in dogs Darcy B. Adin 1; Clarke Atkins2; Steven Friedenberg3; Joshua Stern4; Kathryn Meurs2 1University of Florida; 2North Carolina State University; 3University of Minnesota; 4University of California, Davis The angiotensin‐converting enzyme (ACE) gene intronic polymorphism at canine chromosome 9:11507816:G>A has recently been shown to increase the magnitude of aldosterone breakthrough, despite adequate suppression of angiotensin II by ACE‐inhibitors. Genotype influence on non‐angiotensin mediated aldosterone production holds implications for dogs with advanced heart disease, but polymorphism prevalence is unknown. We hypothesized that this polymorphism is more common in some breeds than others and therefore sought to determine prevalence and breed distributions in a large number of dogs. A database of 497 canine whole genome sequences from 54 breeds sequenced for various disease‐specific studies was utilized to genotype dogs at chromosome 9:11507816:G>A. Allele frequency of the polymorphism within the studied population was 20.8%, with 19.9% of dogs heterozygous and 10.8% homozygous. The polymorphism was absent in 22 breeds and present in 32 breeds. Breed predisposition was evaluated for breeds with ≥10 dogs. The polymorphism was overrepresented in Irish Wolfhounds, Dachshunds, Cavalier King Charles Spaniels, Great Danes, and Bull Mastiffs. Irish Wolfhounds were more commonly homozygous than heterozygous. The ACE gene polymorphism was found in nearly a third of dogs, with unequal breed distribution. Some breeds demonstrated high polymorphism prevalence, which may be functionally important for breeds predisposed to heart disease. However, it is possible that the polymorphism prevalence was linked to the disease for which the dogs were sequenced; prevalence within a larger population could vary. Genotyping for this polymorphism may be a step towards personalized medicine and targeted clinical trials in the future of canine medicine. ABSTRACT C22 Left atrial function assessment using tissue motion annular displacement in chronic mitral valve diseased dogs Ana Paula Sarraff 1; Vinícius Silva2; Giovana Tuleski2; Marcela Wolf2; Marconi Farias1; Marlos Souza2 1Pontifícia Universidade Católica do Paraná (PUCPR); 2Federal University of Paraná (UFPR) A strong correlation between left atrial dysfunction, heart disease severity and prognosis are observed in dogs with myxomatous mitral valve disease (MMVD). The methods used to evaluate left atrial function are highly dependent on technical factors, are difficult and time consuming to use in clinical practice. The aims of this study were to study longitudinal left atrial function in dogs with chronic mitral valve disease by Tissue Motion Annular Displacement (TMAD), correlate TMAD with other echocardiographic methods of left atrial function and compare sensibility and specificity of this new tool to differentiate MMVD stages. In this prospective cross‐sectional study, one hundred fifty‐five client‐owned dogs, including 95 dogs with myxomatous mitral valve disease (MMVD) and 60 healthy control dogs underwent echocardiogram. The animals were divided into A (control), B1, B2, C and D groups, according to ACVIM consensus. Left atrial function was assessed by biplanar area‐length method, LA global strain (by speckle tracking), tissue Doppler imaging (mitral A′) and TMAD (global and systolic) (by speckle tracking). Left atrial reservoir function was evaluated by LA global TMAD, LA global strain and LA emptying fraction and LA systolic function by LA systolic TMAD, LA ejection fraction and mitral A′. Data underwent the Shapiro‐Wilk test to check for a normal distribution. Left atrial global TMAD was greater in B2, C and D groups (p < 0.001) and LA systolic TMAD was greater in B1, B2 and C and lower in D group (p = 0.002). Left atrial global TMAD was an excellent method to differentiate dogs without (B1) from with remodeling (B2, C and D) (p < 0.05), whereas global strain and ejection fraction were better to discriminate the asymptomatic (B1 and B2) from the symptomatic (C and D) dogs (p < 0.05) (Table 1). According to ROC analysis, the best discriminator between the asymptomatic from symptomatic and between animals with and without cardiac remodeling was LA global TMAD (AUC = 0.715; AUC = 0.756). Left atrial global TMAD value with optimal sensitivity and specificity to distinguish asymptomatic from symptomatic dogs was 21.07 mm/m2 (sensitivity 61.1% and specificity 76.3%) and animals with from without cardiac remodeling was 17.59 mm/m2 (sensitivity 66% and specificity 81%). The best method to discriminate asymptomatic from symptomatic animals and with from without cardiac remodeling was LA global TMAD. This method can be used as complementary, in conjunction with traditional echocardiographic examination, to assess global atrial function in patients with MMVD. A strong correlation between left atrial dysfunction, heart disease severity and prognosis are observed in dogs with myxomatous mitral valve disease (MMVD). The methods used to evaluate left atrial function are highly dependent on technical factors, are difficult and time consuming to use in clinical practice. The aims of this study were to study longitudinal left atrial function in dogs with chronic mitral valve disease by Tissue Motion Annular Displacement (TMAD), correlate TMAD with other echocardiographic methods of left atrial function and compare sensibility and specificity of this new tool to differentiate MMVD stages. In this prospective cross‐sectional study, one hundred fifty‐five client‐owned dogs, including 95 dogs with myxomatous mitral valve disease (MMVD) and 60 healthy control dogs underwent echocardiogram. The animals were divided into A (control), B1, B2, C and D groups, according to ACVIM consensus. Left atrial function was assessed by biplanar area‐length method, LA global strain (by speckle tracking), tissue Doppler imaging (mitral A′) and TMAD (global and systolic) (by speckle tracking). Left atrial reservoir function was evaluated by LA global TMAD, LA global strain and LA emptying fraction and LA systolic function by LA systolic TMAD, LA ejection fraction and mitral A′. Data underwent the Shapiro‐Wilk test to check for a normal distribution. Left atrial global TMAD was greater in B2, C and D groups (p < 0.001) and LA systolic TMAD was greater in B1, B2 and C and lower in D group (p = 0.002). Left atrial global TMAD was an excellent method to differentiate dogs without (B1) from with remodeling (B2, C and D) (p < 0.05), whereas global strain and ejection fraction were better to discriminate the asymptomatic (B1 and B2) from the symptomatic (C and D) dogs (p < 0.05) (Table 1). According to ROC analysis, the best discriminator between the asymptomatic from symptomatic and between animals with and without cardiac remodeling was LA global TMAD (AUC = 0.715; AUC = 0.756). Left atrial global TMAD value with optimal sensitivity and specificity to distinguish asymptomatic from symptomatic dogs was 21.07 mm/m2 (sensitivity 61.1% and specificity 76.3%) and animals with from without cardiac remodeling was 17.59 mm/m2 (sensitivity 66% and specificity 81%). The best method to discriminate asymptomatic from symptomatic animals and with from without cardiac remodeling was LA global TMAD. This method can be used as complementary, in conjunction with traditional echocardiographic examination, to assess global atrial function in patients with MMVD.   ABSTRACT C23 Electrocardiography in dogs with mammary tumors Gabriela Bahr Arias; Mariângela Kilpp Oliveira; Josiana Schnitzer; Giovana Di Santis; Maria Isabel Martins; Fabio Gava Londrina State University Malignant tumors can cause paraneoplastic syndrome and consequent cardiovascular disorders. The objective of this study was to evaluate the electrocardiography (ECG) in bitches with mammary tumors in order to detect significant changes in cardiac rhythm, ECG waves, segments or cardiac axis. Twenty‐nine female dogs were used in this study (dogs with mitral valve disease were excluded), allocated in three groups: G1: control group (n = 10), G2: benign neoplasia group (n = 6) and G3: malignant neoplasia group (n = 13), being considered malignant or not after histopathological analysis. Five minutes of computerized ECG record was used and statistical analysis was performed by analysis of variance followed by Tukey's test. This study was approved by the local ethics committee. The most prevalent type of neoplasia in G2 was the benign mixed tumor (83%), followed by adenoma (17%) whereas in G3: carcinoma in a mixed tumor (61%); papillar carcinoma (23%); tubular carcinoma (8%) and carcinosarcoma (8%). Regarding cardiac rhythm, it was found sinus arrhythmia (SA) and normal sinus rhythm (NS): G1: 50% SA and 50% NS; G2: 67% SA and 33% NS; G3: 54% SA and 46% NS. No ventricular or atrial arrhythmias were detected. For other parameters in G1, G2 and G3, respectively (mean ± Std error): FC (bpm): 110 ± 9.2, 120 ± 8.5, 124 ± 7.5; P (ms): 48 ± 1.6, 51 ± 1.8, 50 ± 1.2; P (mV) 0.19 ± 0.02, 0.2 ± 0.02, 0.19 ± 0.02; PR (ms): 94 ± 4.3, 93 ± 5.5, 89 ± 3.9; QRS (ms): 56 ± 1.54, 60 ± 4, 62 ± 1.2; R (mV): 1.1 ± 0.06, 1.2 ± 0.24, 0.9 ± 0.13; QT (ms): 203 ± 9.4; 204 ± 7.9; 197 ± 13.8; and cardiac axis (°): 66 ± 6.2, 61 ± 7.9, 70 ± 7.5. There were no significant differences for all these parameters and also for ST interval and T wave morphology, concluding that ECG has no changes in benign or malignant mammary tumors in dogs. ABSTRACT C24 Comparison of heart rate obtained using AliveCor electrocardiography to 24‐hour Holter in canine atrial fibrillation Sumana Prabhakar; Tamilselvam Gunasekaran; Robert Sanders Michigan State University Canine atrial fibrillation (AF) is commonly managed through pharmacological heart rate (HR) control. Accurate HR assessment is required to determine the need for HR control therapy and to monitor drug efficacy. Heart rate obtained using in‐hospital electrocardiography (ECG) has been shown to be inaccurate in dogs likely due to heightened sympathetic tone. Twenty‐four‐hour continuous ambulatory ECG monitoring (Holter) provides at‐home HR data and valuable prognostic information. The mean 24‐hour Holter HR of less than 125 bpm has been shown to be associated with survival. However, Holter monitoring is not always feasible in a primary care setting due to the need for additional equipment. The AliveCor smartphone ECG has been shown to produce accurate instantaneous HR in dogs with sinus rhythm and presents a possible alternative to Holter monitoring for at home HR assessment. The objectives of this study are 1. To determine the accuracy of the AliveCor ECG to estimate HR in AF by comparing HR obtained using AliveCor ECG to the corresponding Holter ECG. 2. To compare 24‐hour Holter mean HR to the mean HR obtained using multiple one and five‐minute AliveCor ECG recordings in dogs with AF. Dogs with AF underwent Holter monitoring. Simultaneously, an AliveCor electrode was adhered to the left side of each dog's chest (AliveCorattach) and an area was prepared on the right side of the dogs' chest for the owners to place an additional AliveCor electrode (AliveCorowner). The owners were instructed to record four five‐minute resting ECGs on their personal smartphones (AliveCor Vet smart phone application) using both AliveCor electrodes. The accuracy of AliveCor ECG was assessed by comparing the HR obtained from each AliveCor electrode to the HR calculated from the simultaneous Holter recording. AliveCor ECG obtained HR measurements for one and five minute recording durations were compared to 24‐hour mean HR using modified Bland Altman limits of agreement (LOA) plots. A total of 11 dogs were enrolled. One dog was excluded due to poor quality of the AliveCor ECG tracings and one dog was excluded due to an inability to match the timing of Holter and AliveCor ECGs. Seven out of 9 dogs were receiving drug therapy to control HR. All 9/9 dogs had at least a single one minute recording and 8/9 dogs had at least a single five minute recording for both AliveCorattach and AliveCorowner. A complete data set was obtained from 3/9 dogs. As only 3/9 dogs had complete data sets, we were only able to compare a single, one minute and five minute AliveCor HR to the 24‐hour Holter mean HR. The median difference between the HR provided by all the available five minute AliveCorattach and AliveCorowner to the simultaneous Holter ECG was 4 beats per minute (bpm) (IQR = 1.4 to 14 bpm) and 7 bpm (IQR = 4.3 to 12 bpm) respectively. The median difference between the HR provided by one minute AliveCorattach and AliveCorowner to the simultaneous Holter ECG was −0.5 beats per minute (IQR = −5 to 8.5 bpm) and −4 bpm (IQR = −10 to −0.5 bpm) respectively. The median HR difference between AliveCor HR and simultaneous Holter ECG HR was not significantly different between AliveCorattach and AliveCorowner for either recording durations. No significant correlation was found between the recording duration to the median difference between AliveCor HR and simultaneous Holter ECG HR. Comparison of a single five minute AliveCorattach HR and AliveCorowner HR to 24‐hour Holter mean HR using the modified Bland‐Altman LOA plots revealed a mean difference of 1 bpm (LOA = −30 to 29 bpm) and 2 bpm (LOA = −36 to 39 bpm) respectively. Comparison of a single one minute AliveCorattach HR and AliveCorowner HR to 24‐hour Holter mean HR using the modified Bland‐Altman LOA plots revealed a mean difference of 9.5 bpm (LOA = −51 to 32 bpm) and 4.5 bpm (LOA = −41 to 50 bpm) respectively. The median HR difference between the 24‐hour Holter mean HR and HR obtained using AliveCor ECG was not significantly different between one and five minute AliveCor recordings. All the HR values provided by five minute AliveCorowner recordings were within 20% range from 24‐hour mean HR, while 87.5% of the HR values were within similar range for AliveCorattach recordings. One minute AliveCorattach recording provided 88% of the HR values within 20% range from 24‐hour mean HR as compared to 77% HR values within similar range for AliveCorowner recordings. This study shows that the AliveCor ECG can provide reasonable estimates of simultaneous HR in dogs with AF. The wide LOA between AliveCor ECG HR and the 24‐hour mean HR, makes a single, one or five minute AliveCor ECG recordings, unreliable for HR assessment in an individual dog with AF. In this study, due to poor owner compliance we were not able to compare more than a single, one or five minute AliveCor ECG recordings to 24‐hour Holter mean HR. ABSTRACT C27 Transvenous thromboembolic coiling of feline patent ductus drteriosus Brittany Stewart; Christopher Stauthammer University of Minnesota Minimally invasive per‐catheter occlusion of Patent Ductus Arteriosus (PDA) in feline patients is limited due to femoral vascular diameter. Surgical ligation has historically been the treatment of choice. The purpose of this study is to assess the safety and efficacy of transvenous thromboembolic coiling in cats as a valid treatment option for PDA occlusion. Client‐owned cats with left to right shunting PDAs underwent minimally invasive occlusion via a transvenous approach using a Flipper detachable coil (Cook Medical LLC, Bloomington, IN). Minimal ductal diameter and ampulla diameter measurements were taken via transthoracic echocardiography and angiography. Ductal occlusion was evaluated on transthoracic echocardiography performed <24 hours post procedure and during long term follow‐up (recommended at 3 months with additional recheck frequency decided based on residual flow). Residual ductal flow was graded based on color Doppler. A total of 7 cats, median weight 3.5 kg (1.9–4.8) and age 259 days (105–668) were enrolled. PDA morphology types 2a (3), 2b (3), and 3 (1) were represented. Based on echocardiography, the ductal ampulla diameter was 4.1 mm (1.2–6.5) and the minimal ductal diameter was 2.9 mm (0.7–5.8). Based on angiography, the ductal ampulla diameter was 5.9 mm (4–8) and the minimal ductal diameter was 2.3 mm (1.2–5.5). Flipper coil diameters ranged from 5 to 8 mm varying from 5 to 12 cm in extended length. Coil placement was successful in 6 of the 7 cases (86%). One patient (type 3 morphology) was unable to have the coil (8 mm/12 cm) safely deployed based on size of ampulla (8 mm) and the procedure was converted to surgical ligation. Average fluoroscopy time was 32.5 minutes (16.9–57.6). There were zero incidents of device embolization or perioperative death. All patients were provided pain medication and antibiotics post procedure. Residual flow was noted on the <24‐hour post echocardiogram in three of the six successful cases (50%) with all considered moderate in severity. Follow up echocardiogram (mean 235 days post procedure) revealed residual flow in two cases; one trivial and one moderate in severity. Transvenous thromboembolic coiling in cats with type 2a and 2b morphology appears to be a safe and effective approach to PDA occlusion regardless of patient's size. In cats with larger PDA measurements and/or type 3 morphology, standard surgical ligation is still likely the best approach though further investigation is warranted. Especially with measurement inconsistencies between transthoracic echocardiography and angiography, the best occlusion approach may need to be made intra‐operation. ABSTRACT C28 Comparison of 3D printing segmentation software programs for veterinary cardiology applications Kaitlin M. Abbott‐Johnson 1 ; Susanne Stieger‐Vanegas2 1QTest Labs; 2Oregon State University Three‐dimensional (3D) printing is an emerging technology with a wide range of medical applications, but has only been utilized in veterinary cardiology for a few select purposes. As cardiac gated CT and cardiac MRI are more commonly performed in veterinary medicine, it is important to consider the potential ways to utilize these new imaging studies, such as for education and procedural planning purposes. Complex congenital abnormalities can vary between individual cases, and understanding disease variations and especially spatial anatomy can be challenging. Producing digital and printed 3D models can allow deeper understanding of cardiac anatomic pathology. The primary goal of this study was to describe the methods and quantify the time investment necessary for creating 3D cardiac models from diagnostic imaging. The secondary goal was to compare free open source (3D Slicer, NIH, Bethesda, MD) and proprietary 3D modeling (Mimics, Materialise, Belgium) software to create 3D digital images of the heart. The ECG‐gated CT angiography studies of six New World Camelids with confirmed complex congenital abnormalities including truncus arteriosus, tetralogy of Fallot, double outlet right ventricle, coronary anomalies, and ventricular septal defects were selected for this study. 3D bloodpool and myocardial models of each heart were created in each software program. Evaluation of the software included the time needed to create each model type and documentation of the most useful tools and methods used within each program. All 3D cardiac models created had acceptable quality for printing and identification of complex cardiac abnormalities (Figure 1). Creation of 3D bloodpool models was easier and took significantly less time than creating myocardial models (p = 0.021) (Table 1). Myocardial models took approximately 1.2 hours longer to complete in 3D Slicer than in Mimics, but this difference was not statistically significant (p = 0.0711). A limitation of this study is the lack of objective methods to evaluate the accuracy of the final 3D cardiac models. Reported linear measurements utilizing 3D printed bone models are not well suited to evaluate cardiac models, though a recent veterinary orthopedic study showed that 3D Slicer had higher accuracy than other open source programs and the quality of 3D models created was comparable to those created with Mimics. We conclude that when proprietary segmentation software is cost prohibitive, open‐source software is a practical way for veterinarians to create a 3D cardiac model, though more time investment may be needed for segmentation.   ABSTRACT C29 Retrospective investigation of diet and dilated cardiomyopathy (DCM) in dogs Kim J. Freid; Lisa Freeman; John Rush; Suzanne Cunningham; Megan Davis; Emily Karlin; Vicky Yang Cummings School of Veterinary Medicine, Tufts University The FDA has been investigating an apparent association between certain diets and DCM in dogs. The objectives of this study were to (1) compare diets between dogs with DCM and myxomatous mitral valve disease (MMVD) to determine prevalence of non‐traditional diets and (2) retrospectively review DCM cases to determine signalment, diets, echocardiographic changes over time, and outcome. Objective 1: Diet histories of dogs with DCM and those with MMVD examined between May and September, 2018 were compared. Objective 2: Medical records of all dogs diagnosed with DCM between January 1, 2014 and September 30, 2018 were reviewed. Dogs were grouped into traditional or non‐traditional diet categories based on ingredients and whether the manufacturer met World Small Animal Veterinary Association recommendations. Objective 1: 30/33 (91%) of dogs with DCM were eating non‐traditional commercial diets compared to 34/70 (49%) of dogs with MMVD (p < 0.001). Objective 2: 75 dogs with DCM were identified retrospectively: 9 cases in 2014, 8 in 2015, 21 in 2016, 16 in 2017, and 21 in the first 9 months of 2018. Median age was 7.2 yrs (range 0.4–13.6 yrs) and median weight was 37.7 kg (range, 10.0–75.7 kg). The most common breeds were Doberman Pinscher (n = 21) and Great Dane (n = 17), but a variety of breeds were represented. 76.4% of dogs were eating non‐traditional diets. Taurine was measured in 20 dogs: 3/14 had low plasma and 1/18 had low whole blood taurine concentrations. 48 dogs had follow‐up echocardiography. Median survival for all dogs was 293 days (range, 1–1901 days). ABSTRACT C30 Circulating cell free DNA in cats with hypertrophic cardiomyopathy and cardiogenic arterial thromboembolism Arianne F. Fabella 1; Ronald Li1; Stephanie Istvan2; Yu Ueda1; Joshua Stern1 1University of California, Davis; 2Veterinary Specialist Hospital, San Diego Cardiogenic arterial thromboembolism (CATE) is a life‐threatening complication of feline hypertrophic cardiomyopathy (HCM). Clinicians have limited diagnostic tools to identify cats at risk of this devastating outcome. Novel biomarkers may aid in the early detection cats at high risk of CATE. Circulating cell free DNA (cfDNA) has been demonstrated in humans and dogs to play a key role in thrombosis by augmenting the intrinsic pathway and impairing fibrinolysis. Using immunofluorescence, cfDNA in the form of neutrophil extracellular traps has recently been identified as a structural element of feline distal aortic thrombi. Thus, cfDNA is a potential biomarker for assessing thrombotic risk in cats with HCM. This study aimed to characterize and compare levels of circulating cfDNA in cats with CATE (n = 4), in cats with HCM (n = 13) and in clinically healthy cats (n = 18) without HCM. Citrated whole blood was collected following cardiovascular and echocardiographic evaluations. The concentration of isolated cfDNA from plasma was measured by spectrophotometry, followed by agarose gel electrophoresis to determine the size of cfDNA fragments. The mean concentration of plasma cfDNA in cats with CATE was 19.58 ± 20.3 ng/μl compared to those in healthy cats (10.09 ± 4.3 ng/μl) and HCM cats (9.22 ± 5.44 ng/μl) (p = 0.06). Gel electrophoresis identified cats with CATE had longer cfDNA fragments between 150 to 400 base pairs compared to healthy cats and HCM cats with fragments of <50 base pairs. Results of this preliminary study suggest that cfDNA concentrations and cfDNA fragment size may identify HCM cats at risk of thromboembolic complications and continued studies are warranted. ABSTRACT C31 Cellular localization of key proteins controlling pro‐fibrotic pathways in cats with hypertrophic cardiomyopathy Wan‐Ching Cheng 1; Lois Wilkie1; Melanie Dobromylskyj2; Virginia Luis Fuentes1; David Connolly1 1Royal Veterinary College, University of London; 2Finn Pathologists Myocardial fibrosis is one of the major pathological changes in feline HCM. Besides the quantity of collagen deposited, the degree of collagen crosslinking in a collagen bundle also qualitatively affects its structural characteristics and hence the quality of the extracellular matrix (ECM). ECM composed of predominately highly crosslinked collagen will have reduced compliance and pre‐dispose to diastolic dysfunction. Lumican is a small leucine rich protein involved in collagen crosslinking. Recently it was shown that human patients with hypertrophic obstructive cardiomyopathy had increased myocardial lumican, which correlated with cardiac fibrosis determined by late gadolinium enhancement on cardiac magnetic resonance imaging. Furthermore, lumican can induce transcription of LOX (a collagen cross‐linking enzyme), TGF‐β (a potent pro‐fibrotic mediator) and collagen protein in rodent cardiac fibroblasts. We have shown upregulation of Lumican and downstream proteins including LOX and TGF‐β isoforms by Western Blot in the myocardium from cats with HCM. The aim of this present work is to quantify and describe the cellular location of these proteins within the myocardium of HCM cats and explore the SMAD‐dependent TGF‐β signaling in feline HCM. The middle section of the left ventricle from 6 normal control cats and 6 HCM cats presented for necropsy were used. All the hearts underwent histopathological examination. No difference in age and gender was detected between the control and HCM group. Immunohistochemistry was used to localize expression of lumican, LOX, LOXL2, TGF‐β1, TGF‐β2, phosphorylated SMAD2. Using imageJ, the area immunostained for lumican, LOX and LOXL2 (%) was quantified. In addition, activation of fibroblasts was determined by quantifying the area (excluding blood vessels) immunostained for α‐SMA (%). The number of interstitial cells with nuclear staining of p‐SMAD2 was quantified as an indicator for activation of TGF‐β regulated SMAD signaling. Parametric or non‐parametric statistical tests were used where appropriate. Cut‐off for statistical significance was set at 0.05. By immunohistochemistry, lumican localized to the ECM, the cardiomyocytes, and around some infiltrative leucocytes. LOX and LOXL2 localized to cardiomyocytes. LOXL2 also localized to some interstitial cells. Lumican, LOX and LOXL2 (%) were significantly increased in the HCM group (lumican median 36.6% [IQR 26.2–55.7] (n = 4) versus 1.1% [IQR 0.8–2.2] (n = 5); p = 0.016, LOX median 28.2% [IQR 21.3–39.6] (n = 6) versus 1.7% [IQR 1.3–10.1] (n = 5); p = 0.004, LOXL2 median 14.1% [IQR 6.9–15.3] (n = 5) versus 2.7% [IQR 2.1–4.7] (n = 5); p = 0.016) compared to the control group. TGF‐β1 localized to the tunica media of vessels in both groups with the HCM group showing increased immunolabeling. Marked difference existed in the expression of TGF‐β2 between the control and HCM group where the controls had minimal TGF‐β2 expression whereas the HCM cats showed extensive immunolabeling in cardiomyocytes and the tunica media in some vessels. The number of interstitial cells with nuclear translocation of p‐SMAD2, and the area occupied by α‐SMA positive cells (%) were higher in the HCM cats (Interstitial cells Nuclear p‐SMAD2 mean 51.5 [IQR 33.0–95.5], n = 4 versus 12.0 [range 6.0–28.5], n = 5; p = 0.034) (α‐SMA (%) mean 3.42 [IQR 0.38–5.17], n = 6 versus 0.53 [IQR 0.18–0.54], n = 5; p = 0.054) compared to the control cats. In conclusion, lumican was elevated in feline HCM and might promote collagen cross‐linking through increased expression of LOX and LOXL2. The localization of lumican across cell populations in the diseased heart has not been widely explored but our results are in line with the limited published data. Activation of myofibroblasts via TGF‐β2 regulated SMAD signaling could increase collagen production. Together this could result in a less compliant ECM, increased mechanical stiffness and reduced diastolic performance of the left ventricle. ABSTRACT C32 A dose‐ranging study of coenzyme Q10 in dogs with myxomatous mitral valve disease Natalia Druzhaeva; Aleksandra Domanjko Petrič; Gabrijela Tavčar‐Kalcher; Janja Babič; Alenka Nemec Svete Veterinary Faculty, University of Ljubljana Coenzyme Q10 (CoQ10) supplementation improves left ventricular systolic function in advanced heart failure human patients. According to human studies, at least a 3‐fold rise of basal plasma CoQ10 concentration is needed to achieve the biological effects of CoQ10 supplementation. Our goal was to determine the dose sufficient to achieve a 3‐fold increase in CoQ10 plasma concentration in dogs with congestive heart failure (CHF) due to myxomatous mitral valve disease (MMVD). In a randomized, double‐blinded, placebo‐controlled study 19 client‐owned dogs with MMVD and CHF were allocated to 3 groups, receiving water‐soluble CoQ10 in a daily dose either 100 mg (6 dogs), 200 mg (6 dogs) or placebo (7 dogs), divided twice daily, for two weeks as an addition to cardiac therapy. Twelve healthy dogs not receiving CoQ10 were also included. Blood was drawn five times in MMVD patients (basal, 4 hours, one and two weeks after the beginning of supplementation and one week after the last dose) and once in healthy dogs. Liquid chromatography‐tandem mass spectrometry was used to measure plasma CoQ10 concentration. We found no significant difference in basal CoQ10 concentration among groups of patients and healthy dogs (Kruskal‐Wallis test). After two weeks, CoQ10 concentration was significantly higher in both CoQ10 groups compared to their basal concentrations (Wilcoxon test; p < 0.05) and compared to the placebo group (Kruskal‐Wallis test). A dose of 100 mg resulted in 1.7–4.7‐fold and a dose of 200 mg in a 3.2–6.8‐fold increase of plasma CoQ10 concentration. One week after the last dose, CoQ10 concentration decreased in both groups; however, in the 200 mg group, it remained significantly higher in comparison to basal concentration. We found no plasma CoQ10 deficiency in our cardiac patients. A daily dose of 200 mg resulted in at least a 3‐fold increase of plasma CoQ10 concentration in all patients and might be used in supplementation studies in canine CHF patients. ABSTRACT C33 Genetic polymorphisms impact platelet inhibition by clopidogrel in cats with hypertrophic cardiomyopathy Yu Ueda; Maureen Oldach1; Ronald Li1; Eric Ontiveros1; Samantha Fousse1; Karen Vernau1; Michael Court2; Joshua Stern1 1University of California, Davis; 2College of Veterinary Medicine, Washington State University Clopidogrel inhibits adenosine diphosphate (ADP)‐induced platelet activation and is frequently used in cats with hypertrophic cardiomyopathy (HCM) to prevent thromboembolic complications. However, response to clopidogrel has significant interpatient variability in cats. Previous studies reported multiple nonsynonymous single nucleotide polymorphisms (SNPs) within ADP receptor (P2RY1, P2RY12) and cytochrome P450 (CYP) 2C genes. The objective of this study was to determine the impact of the genetic polymorphisms on clopidogrel response in cats with HCM. 49 cats were enrolled after echocardiographic evaluation, baseline blood work, and Doppler blood pressure measurement. Blood samples were obtained before and after 10 to 14 days of clopidogrel therapy, 18.75 mg orally every 24 hours, to assess the degree of platelet inhibition using whole blood platelet aggregometry (Multiplate® analyzer) and flow cytometry. The post‐clopidogrel blood sample was used for quantification of clopidogrel and its active metabolite. One nonsynonymous SNP in both P2RY1 and P2RY12 genes and two in the CYP2C gene were identified. Whole blood platelet aggregometry revealed significant resistance to clopidogrel‐induced platelet inhibition in cats with the P2RY1 variant (P2RY1:A236G) (p = 0.012 for area under the curve [AUC], p = 0.0084 for aggregation, p = 0.037 for velocity). The associations for AUC (p = 0.047) and aggregation (p = 0.034) remained significant after false discovery rate adjustment. No other pharmacogenetic effects were identified for the tested polymorphisms that withstood false discovery rate adjustment. This study demonstrated that a genetic polymorphism in the P2RY1 gene significantly altered response to clopidogrel therapy. ABSTRACT C34 Establishing normal reference intervals for radiographic, echocardiographic, and NT‐proBNP values in apparently healthy kittens Karen M. Vernau1; Catherine Gunther‐Harrington2 ; Ashley Sharpe 3; Yu Ueda2; Ashley Walker4; Elizabeth Montgomery3; Jennifer Surmick3; Nicole Fernandez3; Eric Ontiveros2; Joshua Stern2 1University of California, Davis; 2Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis; 3Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis; 4College of Veterinary Medicine, North Carolina State University Subjective assessment of heart size in kittens is challenging and there is a need for established reference ranges to prevent misdiagnoses of cardiomegaly in this patient population. The purpose of this study was to generate reference intervals for echocardiographic and radiographic quantification of cardiac size in apparently healthy kittens. Eighty‐eight kittens aged 6–16 weeks were included in the study. Radiographic and echocardiographic evaluations were performed without sedation. Echocardiographic images and thoracic radiographs were measured to establish reference intervals for multiple echocardiographic variables, vertebral heart score (VHS) and cardiac thoracic ratio. N‐terminal pro‐brain type natriuretic peptide (NT‐proBNP) was also measured. Statistical correlations between the echocardiographic parameters and age, body weight and sex were all evaluated, and reference ranges were generated. Multiple moderate to strong correlations between body weight and age with various echocardiographic parameters were noted and allometric scaling was performed for body weight. Kittens had a VHS of 9.4 ± 0.73 which is significantly larger (p < 0.0001) and exceeds the previously proposed cutoff of 7.8 in adult cats. Tricuspid regurgitation was a common finding and was present in 37.5% (33/88) of kittens. Measured NT‐proBNP levels were comparable to healthy adult cats with a median of 31 pmol/L (range 24–129 pmol/L). Specific reference ranges are reported in part as Table 1 below and may be utilized when evaluating heart size in this population.   ABSTRACT C35 Clinical usage and tolerability of intravenous pimobendan in dogs suffering from acute congestive heart failure Michael Aherne; John Hertzer; Darcy Adin College of Veterinary Medicine, University of Florida Oral pimobendan is used to treat acute and chronic canine congestive heart failure (CHF). Intravenous pimobendan is not FDA‐approved and is only available in the U.S. with special import license. This retrospective study aimed to evaluate clinical usage and tolerability associated with IV pimobendan administration in dogs with acute CHF. Medical records from 7/2019–1/2020 were reviewed, identifying dogs that received IV pimobendan to treat acute CHF. Controls comprised of age‐ and size‐matched dogs that received only oral pimobendan for acute CHF. Clinical and diagnostic variables, medication dosages, and 30‐day mortality were compared between groups. Data are reported as median(range). Seven dogs received 1(1–6) dose of IV pimobendan at 0.15(0.15–0.16) mg/kg followed by oral pimobendan at 0.38(0.35–0.65) mg/kg q 8(8–12) hours. Controls received 0.34(0.26–0.42) mg/kg oral pimobendan q 12(8–12) hours. No adverse effects were noted. For study vs. control groups respectively, hospitalization time was 47(5–107) vs. 20(8–75) hours, presenting RR was 60(28–100) vs. 60(40–88) breaths/min, cumulative furosemide dose was 9(2.11–30.24) vs. 6.42(2.1–9.98) mg/kg, time to RR <40 breaths/min was 11(1–17) vs. 1(1–3) hours, presenting pulmonary edema score was 7(6–13) vs. 8(4–16). No variables significantly differed between groups. Of the 7 IV pimobendan patients, 3 survived to discharge, 1 died from cardiac arrest and 3 were euthanized due to lack of clinical improvement. Of the 7 control dogs, 5 survived to discharge, and 2 were euthanized. Thirty‐day mortality did not differ between groups. In conclusion, IV pimobendan appears to be tolerated without significant adverse effects in dogs with acute CHF. ABSTRACT C36 Evaluation of cardiac troponin I in neonate dogs born through eutocia Maria Lucia Lourenço; Keylla Helena Nobre Pacifico Pereira; Luiz Eduardo Santos Correia; Viviane Hibaru; Viviane Maria Codognoto; Fabiana Souza; João Carlos Ferreira; Simone Chiacchio School of Veterinary Medicine and Animal Science, São Paulo State University (Unesp) Cardiac Troponin I is a specific biomarker for cardiomyocytic injury and is used to identify myocardial damage through asphyxia in human newborns. However, there are no similar studies pertaining to neonate dogs. This study aimed at evaluating the serum levels of cardiac troponin I in dogs and establish possible correlations with modified Apgar score, heart rate and respiratory rate, blood gas levels, blood sugar levels and weight. A total of 15 neonate dogs of several breeds (Pug, Shih‐tzu and Spitz), all delivered vaginally, were evaluated immediately after birth and after 60 minutes. The reference values adopted for troponin I were <0.006 to 0.05 ng/mL. The mean weight of the puppies was 137.1 ± 38.5 g and the mean values for the parameters at the time of birth were: Apgar score (9 ± 0.9; 10 ± 0), heart rate (208.6 ± 23; 222.4 ± 8.47 bpm), respiratory rate (39.9 ± 8.7; 38.8 ± 11.17 mpm), pH (7.1 ± 0.1; 7.2 ± 0.03), HCO3 (16 ± 4.19; 21.7 ± 3.44 mEq/L), pCO2 (42 ± 8.75; 47 ± 9.03 mm Hg), pO2 (22.3 ± 8.04; 21.6 ± 5.10 mm Hg), sO2 (33.1 ± 16.5; 33.5 ± 9.2 mm Hg), blood sugar (95.9 ± 15.86; 155.7 ± 37.5 mg/dL) and troponin I (0.013 ± 0.007; 0.012 ± 0.006 ng/mL). The neonatal parameters did not diverge significantly between both moments (p < 0.05), and there were no significant correlations between troponin I and the remaining parameters. The newborns presented mixed acidosis (respiratory PCO2 and metabolic HCO3) due to transitory physiological hypoxemia at the time of birth. However, the results obtained from the Apgar score and the blood gas assay indicate that the dogs evaluated in this study were not born asphyxiated (severe hypoxemia) and presented good vitality and favorable clinical conditions, which means the levels of troponin I were within the reference values for healthy animals eutocia delivered. Further studies evaluating asphyxiated neonates born through dystocia or cesarean sections are needed to assess if there are increases in the levels of troponin I, as happens in humans, and ascertain that the biomarker can be an early indicator of myocardial injury in births with severe hypoxemia. Fapesp grant: 2019/21366‐0. ABSTRACT C37 Comparison of different protamine doses for heparin reversal in dogs undergoing mitral valve plasty (MVP) Akane Yoshikawa 1; Haruhiko Suzuki2; Masayuki Enokizono3; Dai Nagakubo4; Naoko Oshima5; Nobuyuki Kanno5 1Nihon University; 2Meguro Animal Medical Center; 3Japan Small Animal Medical Center; 4The University of Tokyo; 5Animal Cardiovascular and Thoracic Surgery Center Protamine is used in patients after cardiopulmonary bypass (CPB) to reverse the anticoagulant effect of heparin. Usually, a dose of protamine equal to 1 mg for each 100 units of heparin is used to reverse the residual heparin activity after CPB. However, overdosing of protamine is known to produce a paradoxical anticoagulant effect in human recently, and may contribute to bleeding. In dogs, protamine administration will induce an anaphylactic response with hypotension as a side effect with high probability, thus determining the proper dose of protamine is necessary. Here, we compared two groups to investigate the optimum dosage of protamine. 25 dogs who underwent MVP under CPB were included. Patients were divided into two groups: High dose (4 mg/kg) protamine group (HD group; n = 13) and low dose (2 mg/kg) protamine group (LD group; n = 12). Activated clotting time (ACT) was used to monitor coagulation and guide management of anticoagulation control in patients undergoing MVP. We administered 400 IU/kg heparin as an initial dose and increased it if it was difficult to maintain the ACT values above 400 seconds during the CPB. Despite the different doses of heparin administrated, the ACT returned to normal values in both groups (HD group: 108.07 seconds, LD group: 106.75 seconds; p = 0.513), and the postoperative total amount of bleeding from chest drainage stayed the same (HD group: 0.43 ml/kg/hour, LD group: 0.64 ml/kg/hour; p = 0.437). These results suggest that it might be possible to decrease the dose of protamine. ABSTRACT C38 Layer‐specific myocardial function assessed by two‐dimensional speckle‐tracking echocardiography in cats with restrictive cardiomyopathy Ryohei Suzuki; Yunosuke Yuchi; Ayaka Niina; Takahiro Teshima; Hirotaka Matsumoto; Hidekazu Koyama Nippon Veterinary and Life Science University Restrictive cardiomyopathy (RCM) is one of the myocardial diseases characterized by restriction of diastolic filling in cats. Layer‐specific myocardial strain obtained by two‐dimensional speckle‐tracking echocardiography is expected to provide additional information for the assessment of myocardial function in cats with cardiomyopathy. However few studies have evaluated the myocardial function in cats with RCM. We aimed to evaluate the layer‐specific myocardial function in cats with RCM. Twelve healthy cats and six cats with RCM were enrolled in this study. Layer‐specific myocardial function (global, endocardial, and epicardial) were compared using left ventricular (LV) longitudinal and circumferential strain (SL and SC), and right ventricular (RV) SL. RV‐SL was measured by tracing only RV free wall or the entire RV wall (6seg). SL were significantly low in cats with RCM compared with controls in the epicardial LV‐SL (13.7% vs. 18.3%), all layers of RV‐SL6seg (global; 20.5% vs. 31.1%, endocardial; 24.9% vs. 35.1%, epicardial; 17.1% vs. 28.0%). Additionally, endocardial‐to‐epicardial LV‐SL ratio was significantly high in cats with RCM (1.5 vs. 1.3) (p < 0.05). SC were significantly low in cats with RCM compared with controls in global and endocardial SC (global; 17.6% vs. 22.2%, endocardial; 31.7% vs. 40.6%) (p < 0.05). Depressed endocardial SC might be a characteristic in cats with RCM, which could be induced by endocardial fibrosis. Additionally, the results of RV‐SL might suggest that RCM could induce the entire RV dysfunction caused by the myocardial fibrosis as with LV, or pulmonary hypertension secondary to LV dysfunction. ABSTRACT C39 Left and right myocardial function in dogs with pulmonary hypertension secondary to mitral valve disease Ryohei Suzuki; Yunosuke Yuchi; Ayaka Niina; Takahiro Teshima; Hirotaka Matsumoto; Hidekazu Koyama Nippon Veterinary and Life Science University Pulmonary hypertension (PH) is a common complication in dogs with myxomatous mitral valve disease (MMVD). In dogs with MMVD, pulmonary artery pressure increases as a consequence of the increased left atrial pressure (passive condition), leading to pulmonary arterial remodeling and increased pulmonary vascular resistance (reactive condition). We hypothesized that right ventricular (RV) function diminished by PH may affect left ventricular (LV) function in dogs with MMVD and PH, especially reactive conditions. We aimed to detect the differences between mild and moderate‐to‐severe PH to compare LV and RV function. Eight healthy dogs, eight dogs with mild PH, and seven dogs with moderate‐to‐severe PH were enrolled in this study. The following indices obtained by two‐dimensional speckle‐tracking echocardiography were compared among controls, mild, and moderate‐to‐severe PH groups: LV and RV longitudinal strain (SL). RV‐SL were measured by tracing only RV free wall or the entire RV wall including interventricular septum (6seg). LV‐SL in mild PH group (24.9%) was higher than controls (16.6%), and lower in moderate‐to‐severe PH group (18.1%). RV‐SL6seg was significantly lower in moderate‐to‐severe PH group (17.3%) than mild PH group (22.5%). In dogs with mild PH, increased LV‐SL and RV‐SL may reflect compensative left and right myocardial function. Whereas, the decreased RV‐SL might be decompensation by advanced pressure‐overload (reactive condition) in dogs with moderate‐to‐severe PH. The decreased LV‐SL might be induced by the decreased RV‐SL because of its low perfusion to LV and paradoxical motion of interventricular septum. Myocardial function may detect reactive PH with poor outcome in dogs with MMVD. ABSTRACT C40 Short‐term evaluation of clinical, radiographic, and echocardiographic effects of patent ductus arteriosus closure in dogs Sage H. Hubert; Sonya Gordon; Ashley Saunders Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Texas A&M University Introduction: Patent ductus arteriosus (PDA), a common congenital abnormality in dogs, results in cardiomegaly and clinical signs. Objectives: To describe pre‐ and short‐term post‐operative results in dogs with isolated PDA and subpopulations with concurrent congenital heart disease (CHD) and that received medical therapy only prior to PDA closure. Methods: Retrospective study of 57 client‐owned dogs with pre‐ and post‐operative imaging within 48 hours of PDA closure. Data collected included signalment, heart and respiratory rates, cardiac medications. Imaging parameters obtained included radiographic vertebral heart size (VHS), vertebral left atrial size (VLAS) and echocardiographic left atrial (LA) and ventricular (LV) size, fractional shortening (FS), transmitral peak E‐wave, concurrent CHD, presence of residual flow. Results: Females represented 70% (40/57). PDA closure methods included surgical ligation (n = 8) or Amplatz canine duct occluder (n = 49). 30/57 were uncomplicated. 14/57 had concurrent CHD (subaortic/aortic stenosis (n = 9), pulmonic stenosis (n = 3), ventricular septal defect (n = 1), mitral dysplasia (n = 1). 19/57 received cardiac medications (furosemide, ACE inhibitor, pimobendan). Significant mean value reduction occurred for each variable (p < 0.015): respiratory rate 38 to 32 breaths/min, heart rate 125 to 107 beats/min, VHS 11.7 to 11.3, VLAS 2.3 to 2.0, LV internal diameter normalized to body weight in diastole 2.21 to 1.82 and in systole 1.40 to 1.33, FS 34.0 to 24.0%, LA to aorta ratio short axis 1.49 to 1.26 and long axis 2.44 to 2.09, E‐wave 0.98 to 0.63 m/s. Residual flow in 1 dog resolved at recheck. Conclusion: PDA closure results in significant reductions in clinical and imaging parameters within 48 hours of closure, including uncomplicated cases. ABSTRACT C41 Prevalence of Maine Coon and Ragdoll associated MYBPC3 mutations in feline population with hypertrophic cardiomyopathy Kerry O'Donnell 1; Darcy Adin2; Clarke Atkins1; Teresa DeFrancesco1 ; Bruce Keene1; Sandy Tou1; Kathryn Meurs1 1College of Veterinary Medicine, North Carolina State University; 2College of Veterinary Medicine, University of Florida Myosin binding protein C3 (MYBPC3) is a component of the sarcomere A band that functions to bind myosin and titin, thereby facilitating sarcomere contractions. Mutations in this gene have been associated with familial hypertrophic cardiomyopathy (HCM) in both human and feline patients. Two cat breeds, the Maine Coon and the Ragdoll, have mutations in the MYBPC3 gene that have been associated with disease. In the Maine Coon cat, a single base pair variation changes the amino acid produced from Alanine to Proline (A31P) and in the Ragdoll cat, a single base pair variation changes the amino acid from Arginine to Tryptophan (R820W). Here, we analyze the prevalence of these breed‐specific mutations in a greater feline population diagnosed with HCM. Samples of DNA were collected from non‐Maine Coon and non‐Ragdoll cats, diagnosed with HCM, through the North Carolina State University College of Veterinary Medicine, Cardiology section from April 2014 to August 2018. DNA was isolated from blood or buccal swab and endpoint genotyping was performed with previously designed probes and protocols to test for the A31P and R820W mutations. A total of 109 samples were collected from cats of the following breeds: Domestic Shorthair (80), Domestic Longhair (12), Persian (4), Siberian (4), Bengal (4), Domestic Medium Hair (2) Rex (1), Siamese (1) Norwegian (1). All cats were negative (homozygous wildtype) for both mutations. The absence of two breed‐specific mutations in this general population sampling of cats with HCM reinforces the allelic heterogeneity of feline HCM, with different breed types being associated with different disease‐causing mutations. This is supported by the human model of the disease, in which over 7000 MYBPC3 mutations have been identified, and 230 have been pathogenically associated with disease. The value of genetic testing for either known MYBPC3 mutation in the overall feline HCM population is likely minimal. ABSTRACT C42 Role of echocardiographic views adapted for lung evaluation in diagnosis of pulmonary edema in dogs Marlos Gonçalves Sousa; Bruna Bruler; Amalia Giannico; Marcela Wolf Federal University of Paraná (UFPR) The purpose was to test a lung‐ultrasound‐like technique during echocardiographic examination to help identify the cause of dyspnea in dogs. 75 dogs were enrolled into 5 groups: (1) control, (2) MMVD stage B2 with mitral E peak velocity <130 cm/s and E/IVRT <2.5, (3) MMVD B2 with mitral E peak velocity >130 cm/s and E/IVRT >2.5, (4) cardiogenic edema and (5) pulmonary disease. Chest x‐rays were used as gold standard tests. Loop recordings with decreased depth, placement of the heart in the upper 1/3 of the screen and change of focal point to the lung plane were used for posterior evaluation in the following standard echocardiographic views: apical 4 chambers, long axis 4 chambers, short axis at aortic level and short axis at papillary muscle level. Videos were classified as negative and positive based on the number of B‐lines (0, 1 or 2 and 3 or >3). A positive classification was able to differentiate dogs with cardiogenic edema or pulmonary disease from dogs in the other three groups in all four adapted views. The best views for identification of edema or lung disease were right parasternal short axis at papillary muscle level and long axis 4 chambers view. Interobserver tests showed a kappa of 0.88 and 0.86 for right parasternal short axis at papillary muscle level and long axis 4 chambers, respectively. We've concluded that echocardiographic views adapted for lung evaluation, in addition to echocardiographic parameters, may aide in differential diagnosis of dyspnea in dogs. ABSTRACT C43 Myocardial transcriptome profiling in cats with and without hypertrophic cardiomyopathy Jessica Joshua; Jeff Caswell; Sonja Fonfara University of Guelph Feline hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. Although, genetic mutations have been identified for certain breeds, not all cats with mutations develop HCM, indicating incomplete penetrance. Therefore, other genes and their expression levels may be important in uncovering HCM pathophysiology. However, myocardial mRNA profiles for feline HCM are unknown. We hypothesize that the myocardial transcriptome will differ in cats with HCM compared to healthy cats. To determine mRNA profiles, RNA was isolated from the left ventricle (LV) and left atrium (LA) of 5 healthy cats and 5 cats with HCM. Expression levels were quantified using next generation sequencing and compared using bioinformatic tools for differential gene expression and principal component analysis. First, we found 355 genes were differently expressed (DE) in HCM LV compared to control LV. Second, we identified 122 DE genes in HCM LA compared to control LA, of which 11 are already known to be associated with HCM. Third, we detected 1509 DE genes in HCM LA compared to HCM LV, 16 of which are currently linked to HCM. Overall, we show myocardial global mRNA profiles in healthy cats and altered expression profiles in cats with HCM and between cardiac regions. Our findings may help in detecting novel genes and pathways involved in HCM to benefit feline health. ABSTRACT C44 Tricuspid annular plane systolic excursion normalized by right ventricular size in dogs with pulmonary hypertension Yunosuke Yuchi; Ryohei Suzuki; Ayaka Niina; Takahiro Teshima; Hirotaka Matsumoto; Hidekazu Koyama Nippon Veterinary and Life Science University Tricuspid annular plane systolic excursion (TAPSE) is one of right ventricular (RV) systolic function indicators. There was no significant difference for TAPSE among severity groups of pulmonary hypertension (PH) secondary to myxomatous mitral valve disease (MMVD) because of its load dependency. We hypothesized that TAPSE normalized by RV size could assess RV function regardless of RV load. We aimed to evaluate the utility of TAPSE normalized by RV size. Twenty healthy dogs and sixty‐eight dogs with MMVD were enrolled in this study. The following indices were measured as the indicators of RV size; end‐diastolic RV internal dimension (RVIDd), end‐diastolic and end‐systolic RV area (RVEDA and RVESA), and end‐diastolic RV wall thickness. TAPSE was measured by B‐mode and M‐mode methods, and TAPSE normalized by body weight (TAPSEn) was also calculated. TAPSE normalized by RV size were calculated as TAPSE divided by each RV size indices in the same cardiac cycles. We compared all indices among PH severity groups and presence or absence of right‐sided congestive heart failure (R‐CHF), and reproducibility was also assessed. There was no significant difference in TAPSE and TAPSEn. Whereas, all indices about TAPSE normalized by RV sizes were significantly decreased in dogs with severe PH and R‐CHF. TAPSEB‐mode/RVIDd and TAPSEB‐mode/RVEDA had high reproducibility, sensitivity, and specificity to detect the R‐CHF. TAPSE normalized by RV size could reflect RV dysfunction, which could not be detected by non‐normalized TAPSE. Additionally, TAPSEB‐mode/RVIDd and TAPSEB‐mode/RVEDA might be useful to estimate the onset of R‐CHF. ABSTRACT C45 P‐wave terminal force in dogs with naturally occurring myxomatous mitral valve disease Karla L. Calderón Olaguivel; Marcela Wolf; Vinícius Costa Silva; Giovana Ruviaro Tuleski; Bruna Bruler; Marlos Sousa Federal University of Paraná In medicine, P‐wave terminal force in precordial lead V1 (PTFV1) is the most widely used electrocardiographic criteria to assess left atrial abnormalities. It is the algebraic product of the amplitude and the duration of the negative deflection at the end of P‐wave in precordial lead V1. In veterinary, PTFV1 is still an unexplored electrocardiographic parameter. Myxomatous mitral valve disease (MMVD) is the most common cardiac disease in dogs. Progressive degeneration of the mitral valve predisposes to left‐sided volume overload and chamber enlargement. We sought to investigate the existence of PTFV1 and its value as electrocardiographic marker of left atrial remodeling in a population of dogs with naturally occurring MMVD. Forty‐seven healthy dogs (control group) and seventy‐four client‐owned dogs with MMVD were enrolled in this prospective investigation. All dogs underwent a three‐minute electrocardiographic recording with all frontal leads and three simultaneous locations for precordial lead V1: first intercostal space at the level of the costo‐chondral junction (1CCJ), third intercostal space at the level of the costo‐chondral junction (3CCJ), and fifth intercostal space at the level of the esterno‐chondral junction (5ECJ). A single PTFV1 value for each precordial lead location was obtained after averaging five representative PTFV1 values. Also, standard echocardiography was performed in all dogs. In 1CCJ and 3CCJ locations, P‐wave was negative. In consequence, PTFV1 was found as a positive deflection at the end of P‐wave. In the control group, PTFV1 was detected in 96% (45/47) of dogs at both 1CCJ and 3CCJ locations (1.36 ± 0.28 and 1.7 ± 0.44, respectively). Frequency of detection of PTFV1 at 5ECJ was similar to 1CCJ and 3CCJ in control dogs, but notably diminished in MMVD groups. ROC curves evaluating sensitivity and specificity of PTFV1 to differentiate controls and MMVD dogs at 3CCJ, produced an AUC = 0.6137 (p < 0.05). In the same way, ROC analysis to differentiate controls and dogs with enlarged left atrium obtained an AUC = 0.672 at 1CCJ, while at 3CCJ we documented an AUC = 0.6933. In MMVD group, weak positive correlations were found between PTFV1 values at both 1CCJ and 3CCJ locations and left atrium‐to‐aorta ratio, diastolic left ventricular internal diameter, normalized diastolic left ventricular internal diameter and E‐wave. In addition, a correlation existed between normalized left ventricular internal parameter and 1CCJ PTFV1 when only dogs with enlarged left atrium were considered (r = 0.42; p < 0.05). In conclusion, our study found that PTFV1 was best identified at 1CCJ and 3CCJ locations and showed a polarity opposite to the one in man. Differences in mean vector of atrial activation and distribution of electrical potentials on body surface might justify such contrasting finding. In the same way, PTFV1 lacks accuracy to distinguish between healthy and MMVD dogs, but its performance was a bit better when only B2, C and D MMVD dogs, i.e., dogs with enlarged left atrium, were considered. Moreover, there were positive correlations between PTFV1 values and echocardiographic surrogates of left atrium dilation and congestion. To the best of the author's knowledge, this study is pioneer in evaluating PTFV1 as an electrocardiographic marker in dogs with MMVD. Further studies are warranted to better clarify its applicability in other cardiac diseases, and well as the role played by the thorax conformation in detecting PTFV1 in dogs. ABSTRACT C46 Real‐time dosimetry monitoring in the interventional catherization laboratory Kursten V. Pierce; Brian Scansen; Nicole Maddox Colorado State University Exposure to low‐dose ionizing radiation during fluoroscopic procedures is a health risk for operators and staff in veterinary catheterization laboratories, though data is lacking for typical exposure levels per case and by staff member. The study aim was to determine radiation exposure to all staff members for various interventional procedures. Radiation exposure was collected prospectively using a real‐time dosimetry monitoring system from September 2018 to January 2020. Procedure type, fluoroscopy time, and real‐time individual doses to operators and staff were collected. Complete data was obtained from 105 procedures: balloon pulmonary valvuloplasty (BPV, n = 38), transvenous pacemaker implantation (27), patent arterial duct occlusion (PDA, 25), diagnostic right heart catheterization (5), percutaneous embolization for portocaval shunts (4), transarterial chemoembolization for hepatocellular carcinoma (3), and tracheal stenting (3). Median radiation dose exposure over all procedures was significantly higher for cardiology residents (4.93 μSv, IQR 1.59–15.64) compared to faculty (3.46 μSv, 0.64–13.02), anesthetist (0.53 μSv, 0.10–2.43) and transesophageal sonographer (TEE, 0.46 μSv, 0.35–2.20), while the lowest exposure was recorded by the technician (0.001 μSv, 0–0.10) (p < 0.0001). Median doses to faculty, resident, anesthetist, TEE, and technician during BPV were 4.33 μSv, 13.80 μSv, 0.57 μSv, 0.46 μSv, and 0.001 μSv. Median doses in the same order for PDA were 0.67 μSv, 3.40 μSv, 0.67 μSv, 0.63 μSv, and 0.01 μSv. Median doses to faculty, resident, anesthetist, and technician during pacemaker were 2.48 μSv, 3.05 μSv, 0.03 μSv, and 0.01 μSv. These data provide information on dose to operator for fluoroscopic procedures performed in animals. Real‐time dosimetry monitoring may enhance radiation awareness, optimizing radiation safety practices for all interventional team members. ABSTRACT C47 Pharmacokinetics and relative bioavailability of pimobendan and O‐desmethyl pimobendan in healthy dogs after rectal administration Jiwoong Her 1; Dawn Boothe2; Lenore Bacek3; Crisanta Cruz‐Espindola2 ; Randolph Winter4; Kendon Kuo2 1Department of Clinical Sciences, College of Veterinary Medicine, Auburn University; 2College of Veterinary Medicine, Auburn University; 3BluePearl Veterinary Partners; 4The Ohio State University Pimobendan is used as therapy for acute congestive heart failure (CHF) in dogs with advanced cardiac disease. In some patients with CHF, oral administration is difficult and increases patient stress. This study aimed to determine if administration per rectum (PR) would be an acceptable alternative to administration per os (PO). Pharmacokinetics of pimobendan and ODMP were prospectively characterized in healthy dogs (n = 8) using a randomized, crossover design with a 24 hr washout after a single dose of pimobendan (0.5 mg/kg) administered either PR or PO. Plasma pimobendan and ODMP were quantitated using HPLC using an assay validated in dogs. Data were subjected to non‐compartmental analysis (Phoenix Winnonlin®). Key parameters (mean ± SD) after PO and PR administration, were, respectively, for pimobendan, peak concentration (Cmax, ng/ml) 49 ± 30.9 vs. 10 ± 1.95, time to reach Cmax (Tmax, hr) 2.07 ± 0.93 vs. 1 ± 0.42, disappearance half‐life (T½, hr) 1.83 ± 0.80 vs. 2.20 ± 0.58, and area under the concentration‐time curve (AUC0–∝ ng/ml/hr), 148 ± 71 vs. 31 ± 12, with a relative bioavailability (F) of 0.24. For ODMP, PO vs. PR, respectively, Cmax was 31 ± 10 vs. 8.8 ± 4.76, Tmax of 3.2 ± 1.6 vs. 1.65 ± 1.1, T½ was 4.96 ± 2.74 vs. 8.34 ± 4.81, AUC0–∝ was 168 ± 36 vs. 50 ± 19, F of 0.27. The F of ODMP vs. pimobendan was 1.31 (PR) and 1.51 (PO). This study demonstrates pimobendan may achieve potentially therapeutic concentrations when administered PR at 0.5 mg/kg. ABSTRACT C48 Repeat balloon valvuloplasty for dogs with pulmonary valvar restenosis Randolph L. Winter 1; Jaylyn Rhinehart1; Amara Estrada2; Herbert Maisenbacher3; Thaibinh Nguyenba4; Brian Scansen5; John Bonagura6; Karsten Schober1 1College of Veterinary Medicine, The Ohio State University; 2College of Veterinary Medicine, University of Florida; 3Veterinary Heart Care; 4MedVet Medical and Cancer Centers for Pets; 5College of Veterinary Medicine, Colorado State University; 6College of Veterinary Medicine, North Carolina State University Pulmonary stenosis (PS) is a common congenital defect in the dog, characterized by valve leaflet dysplasia, fusion, or both. Severe valvar PS can be treated with balloon valvuloplasty (BV) to reduce the obstruction severity and improve clinical signs. Typically, additional interventional procedures are unnecessary, as restenosis rates are reportedly low in both dogs (10–17%) and in humans. Repeated pulmonary BV in humans is generally successful and safe, but outcomes in dogs with pulmonary restenosis have not been reported. This retrospective study describes procedural outcomes and length of time between procedures in dogs undergoing multiple BV procedures for pulmonary valvar restenosis. Medical records and stored echocardiographic images were reviewed. Measured variables included maximum systolic ejection velocity (PVmax) and velocity time integral (VTI); maximal pressure gradient across the pulmonary valve (maxPG) was calculated as maxPG = 4 V2. Twelve dogs were included; one underwent three procedures. Median time between BV procedures was 31.4 months (range: 6.0 to 120.7). One dog died during repeat BV, but no others experienced adverse effects. Mean reductions in PVmax, max PG, and VTI following initial and repeat BV were 1.9 m/sec, 79.3 mm Hg, 45.1 cm, and 1.53 m/sec, 63.8 mm Hg, 31.4 cm, respectively (all p < 0.01). Differences in pre‐BV and post‐BV PVmax, max PG, and VTI were not different between initial and repeat BV (p = 0.42, p = 0.64, p = 0.37). This study suggests that repeat BV for dogs with pulmonary valvar restenosis might be effective and safe in a majority of canine patients. ABSTRACT C49 Congestive heart failure affects peripheral blood lymphocyte subtypes in canine myxomatous mitral valve disease Natalia Druzhaeva 1; Alenka Nemec Svete1; Alojz Ihan2; Katka Pohar3; Aleksandra Domanjko Petrič1 1Veterinary Faculty, University of Ljubljana; 2Faculty of Medicine, University of Ljubljana; 3Faculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana The inflammatory response is a part of the pathophysiology of congestive heart failure (CHF), and studies show that lymphocytes play a role in this process. We aimed to compare lymphocyte and their subtype concentrations and proportions and correlate them to the stage of the disease in dogs with different stages of myxomatous mitral valve disease (MMVD) and healthy dogs. In a prospective cross‐sectional study, we included 65 dogs with MMVD in 3 ACVIM stages (B2, C2, and C1+D) receiving cardiac treatment (where indicated) and 13 healthy controls aged 5 to 12 years. Fresh whole blood samples were analyzed with multicolor flow cytometry using rat and mouse anti‐canine antibodies (BioRad) for T lymphocytes (CD3+), including T helper lymphocytes (CD3+CD4+), cytotoxic T lymphocytes (CD3+CD8+), and B lymphocytes (CD45+CD21+). Plasma NT‐proBNP concentrations were measured using IDEXX ELISA and serum cardiac troponin I (cTnI) concentrations were measured using a high‐sensitivity immunoassay (ADVIA Centaur TnI‐Ultra; Siemens). Dogs in CHF (stages ACVIM C2 and ACVIM C1+D) had significantly (p < 0.05) lower percentages of CD3+CD4+ and significantly higher percentages of CD3+CD8+ (one‐way ANOVA, Tukey post hoc test) as well as significantly lower CD4+/CD8+ ratio (Kruskal‐Wallis; pairwise comparisons with Bonferroni corrections) in comparison to healthy controls. We did not find any significant differences in total lymphocyte concentration and percentage, as well as concentrations and percentages of T and B lymphocytes among different groups of cardiac patients and healthy controls. Plasma NT‐proBNP concentrations significantly differed among groups of patients and healthy dogs, except for healthy and ACVIM B2; however, NT‐proBNP did not correlate significantly (Spearman test) with any of the lymphocyte subtypes. Cardiac troponin I concentrations significantly differed among groups and correlated significantly negatively with B lymphocyte concentration and proportion of CD3+CD4−CD8− (double negative T lymphocytes) in ACVIM B2, positively with proportion and concentration of CD3+CD4+CD8+ (double‐positive T lymphocytes) in ACVIM C2, and positively with concentration of CD3+ (T lymphocytes) in ACVIM C1+D group (Spearman test). We found that the proportion of cytotoxic T lymphocytes is increased, and the proportion of T helper lymphocytes decreased in CHF in dogs with MMVD but not in the ACVIM B2 group. ABSTRACT C50 Mathematical prediction of Infiniti Medical Standard and duality tracheal stents deployed length Eric De Madron Central Hospital for Veterinary Medicine Careful selection of a tracheal stent is crucial to obtain the best outcome. Currently, the predicted length of the stent once deployed in the trachea is derived from lengthening charts provided by the manufacturer and obtained by measuring the length of the stent under varying degrees of compressions in the workshop. Although useful, these tables do not cover all the possible scenarios, especially when the trachea does not have similar proximal and distal diameters and when the use of a Duality stent is considered. The goal of this study was to establish a mathematical formula allowing prediction of the deployed length of a tracheal stent and to determine whether the results would match the measurements obtained by the engineers. The hypothesis is that the lateral surface of the stent does not change with compression. For a standard cylindrical stent, its lateral surface A = πDL. Therefore, if D1 and L1 are the nominal (uncompressed) length and diameter of the stent, D2 the tracheal diameter and L2 the length of the stent once deployed, one has: πD1L1 = πD2L2. After simplification, one has: D1L1 = D2L2, therefore L2 = L1*D1/D2. The calculated deployed lengths obtained using this formula correlated very well with the measured lengths with a linear regression close to the identity line (Y = 0.9958X + 4.6723, R2 = 0.9796) (Figure 1). Similarly, I used the lateral surface of a truncated cone for the Duality stents: A = 1/2(D + d)πs, s being the slant height: s = √ ((D/2 − d/2)² + L²). If D1 and d1 are the proximal and distal diameters of the nominal stent and D2 and d2 the proximal and distal diameters of the trachea, then: 1/2(D1 + d1)πs1 = 1/2(D2 + d2)πs2, from which (D1 + d1)s1 = (D2 + d2)s2, therefore: s2 = s1(D1 + d1)/(D2 + d2). Again, the predicted deployed lengths obtained using this formula correlated very well with the measured lengths with a linear regression close to the identity line (Y = 0.8968X + 10.992, R2 = 0.8803) (Figure 2). In conclusion, it is possible to mathematically predict the deployed length of a standard cylindrical or asymmetric Duality tracheal stent in a cylindrical or conical trachea. This should help the clinician in the proper selection of the stent prior to deployment.   ABSTRACT C51 Myocardial lumican is associated with fibrosis in cats with hypertrophic cardiomyopathy phenotype Wan‐Ching Cheng 1; Lois Wilkie1; Melanie Dobromylskyj2; Virginia Luis Fuentes1; David Connolly1 1Royal Veterinary College, University of London; 2Finn Pathologists Lumican is a small leucine rich protein with a well characterized function of facilitating collagen organization. Human patients with heart failure have increased quantities of myocardial lumican, which correlate with measures of myocardial fibrosis. in vitro studies in rodent fibroblasts have shown that lumican up‐regulates pro‐fibrotic genes such as TGF‐β, lysyl oxidase (LOX), and collagen I. Recently, by mass spectrometry, it was shown that human patients with hypertrophic obstructive cardiomyopathy had increased myocardial lumican, which correlated with cardiac fibrosis determined by late gadolinium enhancement on cardiac magnetic resonance imaging. Lysyl oxidases are important downstream components of the lumican pathway. They are a group of collagen cross‐linking enzymes that facilitate the maturation of collagen and thereby reduced the susceptibility of collagen to degradation. The aim of this research was to investigate the role of lumican in feline HCM and assess lumican‐associated pro‐fibrotic signaling pathways in cats with HCM. Full thickness tissue from left ventricular free wall sized 1 x 1 x 1 (cm) was collected following necropsy. Ten cats aged between 1.6–18.9 (median 5.8) years were assigned to the normal control group and another 10 cats aged between 1.7–17.0 (median 8.7) years were assigned to the HCM group based on pre‐mortem echocardiography and or/histopathology. There was no difference in the age and sex between the control and HCM group. Transcripts for lumican (LUM), lysyl oxidases (LOX and LOXL2), TGF‐betas (TGFB1 and TGFB2), and collagen (COL1A1 and COL3A1) were quantified using qPCR after reverse transcription with RPS7 and RPL30 being used as reference genes. Immunoblotting was used to quantify the protein products of lumican, LOX, LOXL2, TGF‐β1, and TGF‐β2. The quantity of soluble and insoluble collagen (μg/mg) in 2 control and 4 HCM cats was measured using a Sircol collagen assay, a commercially available colorimetric kit for collagen quantification. Student t test, Mann‐Whitney test, and Welch's t test was used to compare the transcripts level (ΔCt), protein level, and the collagen level, respectively. Correlation of the gene transcripts was assessed using Pearson's test while the association between protein products and the different collagens was assessed using Spearman's test. A p‐value lower than 0.05 was deemed significant. Compared to the control group, the HCM group showed upregulation of all the pro‐fibrotic transcripts except for ACTA2 (which encodes α‐SMA). Lumican transcripts positively correlated with TGFB1, TGFB2, LOX, LOXL2, COL1A1, and COL3A1 transcripts. Lumican transcripts also correlated with the amount of total collagen (μg/mg). Immunoblotting confirmed the presence of lumican as a smear of band at 37–55 kDa and bands at above 100 kDa. Both isoforms of TGF‐beta appeared at around 50 kDa and were elevated in the HCM cats compared to the control cats. LOX and LOXL2 were also increased in the HCM cats compared to controls and were identified at 50 and 75 kDa, respectively. The Sircol collagen assay showed that about 80% of the collagen was insoluble. The 2 controls had significantly higher amount of soluble collagen compared to the 4 HCM cats. In the HCM cats, the insoluble collagen component accounted for higher percentage of total collagen compared to the 2 controls (88–99% vs. 82–87%, p = 0.054). TGF‐β2, but not TGF‐β1, correlated with the amount of total collagen. Moreover, only LOX, but not LOXL2, showed a non‐significant positive trend to collagen cross‐linking (CCL = insoluble collagen/soluble collagen) (r = 0.771, N = 6, p = 0.072). In conclusion, we have shown that lumican is increased in the left ventricle of cats with HCM and is associated with fibrosis potentially by (1) increasing collagen production through TGF‐β signaling and (2) regulating the percentage of insoluble protein through LOX. In human heart disease, increased quantities of insoluble protein are associated with reduced ventricular compliance and diastolic dysfunction. ABSTRACT C52 Metabolic markers of insulin resistance in hypertrophied myocardium of cats Dmitrii Oleynikov Almazov National Medical Research Center, IEM, Saint‐Petersburg, Russian Federation Objectives: Investigation of myocardial tissue concentration of ATP, glucose transporters 1 and 4, pyruvate dehydrogenase, hexokinase 2, insulin receptor, and adropin proteins, determining metabolic changes and possible insulin resistance in feline myocardium with hypertrophic phenotype. Methods: Eighteen cats were studied, divided into 3 groups: without cardiac disease (n = 5), cats with hypertrophic cardiomyopathy (n = 8), cats with chronic kidney disease and secondary myocardial hypertrophy (n = 5). This is the pilot study for metabolic markers determination. Animals in the study were diagnosed for primary disease by standard methods and algorithms. Cats were euthanized due to end‐stage chronic kidney disease, refractory heart failure or by owners will. The material was obtained immediately after death. Samples for the metabolic study were taken from the apical part of the left ventricular free wall and fixed in liquid nitrogen at once and were stored in −80C refrigerator. Studied protein concentrations were analyzed in a specialized research laboratory, using ELISA kits, provided by Cloud‐Clone Corp. (USA), included: total ATP, pyruvate dehydrogenase, hexokinase II, Adropin, insulin receptor, GLUT1, and GLUT4. Results: In the group with HCM, we discovered that levels of ATP, pyruvate dehydrogenase and adropin were severely suppressed in comparison to healthy cats, while GLUT1 and GLUT4 were unchanged. The concentration of hexokinase 2 and insulin receptor proteins was significantly increased. In the group of secondary myocardial hypertrophy, suppression of most studied proteins was admitted, except insulin receptor. Conclusion: In conclusion, we found out that metabolic remodeling and development of insulin resistance in observed diseases with hypertrophy phenotype. We observed depression of pivotal enzymes proteins, limiting energy restoration potency for cardiomyocytes. ABSTRACT C53 The effect of timolol ophthalmic solution 0.5% on systolic function in healthy cats Marlos Gonçalves Sousa 1; Giovana Tuleski2; Vinicius Costa Silva2; Julio Santos2; Matheus Silveira3; Marcela Wolf2; Marlos Sousa2 1Federal University of Parana; 2Universidade Federal do Paraná; 3Instituto Federal Catarinense Introduction: The ophthalmic application of timolol solution 0.5% reduces heart rate (HR) and facilitates the separation of E and A waves on the transmitral flow of cats, after a twenty minutes waiting. It is expected that this beta‐blocker drug will also decrease the contraction force, being the aim of this study to verify if a single drop of a timolol ophthalmic solution decreases the systolic function significantly. Animals: Thirty‐three healthy cats (1–13 years, median six years), 2.1 to 11 kg (median 4.6 kg); 18 females and 15 males; 29 mixed breeds, two Persians, one Maine coon, and one Siamese. Methods: Each cat had a complete echocardiography examination before the administration of a single drop of timolol ophthalmic solution 0.5% at the left eye, repeating the exam 20 minutes later. The parameters used to evaluate the left ventricle (LV) systolic function were: shortening fraction (SF), ejection fraction (EF), Mitral Plane Systolic Excursion (MAPSE), longitudinal Strain (LSt), and Tissue Mitral Annular Displacement (TMAD). The Tricuspid Annular Plane Systolic Excursion (TAPSE) allowed the evaluation of the right ventricle contraction. The variables that helped to asses the left atrium (LA) function were: SF (M‐mode from the LA and aorta view, right parasternal window), Complete ejection fraction (LA cEF), Active ejection fraction (LA aEF), and Passive ejection fraction (LA pEF), TMAD, and LSt. A record of apical 4‐chamber (4AP) and 2‐chamber (2AP) image allowed the off‐line calculation of all TMAD and LSt values. The average AP4 and 2AP values resulted in the Global indexes. All the standard parameters of an echocardiographic exam were made, including Tissue Doppler (TD) of the lateral and the septal mitral annulus for diastolic valuation. For statistical evaluation, SPSS for Windows V.20.0 (SPSS Inc. Headquarters, Chicago, USA) was used. Paired t‐test or Wilcoxon verified differences between animals with and without timolol. The significance level was p < 0.05. Results: As expected, the heart rate (HR) decreased by 19% with timolol. Table 1 shows the results of the systolic evaluation. SF, a classical echocardiographic parameter to evaluate systolic function, reduced 20%. Other systolic variables also decreased: lateral MAPSE (12%), LA SF (16%), Global LA St (12%), Global LA cEF (9%), Global LA aEF (12%). LV St and all TMAD parameters were not affected by the beta‐blocker. The assessment of the diastolic function before and after the timolol is in Table 2. From the thirty‐three cats, only ten presented fused outflow mitral or TD waves before the timolol administration, having timolol succeed help in separating 2 of them. The proportion of fused outflow mitral waves was the same, being timolol effective to separate only the fused lateral TD waves. With lower HR, IRVT values increased 15% after timolol, being most of the IRVT values considered enlarged after the drug administration (>60 ms). Conclusions: Using timolol eye drops to assess cat diastolic function requires careful, as this procedure alters the systolic function parameters used routinely. Less than a third of cats presented fused waves before the timolol administration, being questionable the necessity of this practice on a routine daily basis.   ABSTRACT N01 Functional evaluation of microactuators to prevent hematoma shunt obstruction in an in vitro hydrocephalus model Dillon Devathasan 1; R. Timothy Bentley2; Ángel Enríquez1; Hyowon Lee1; Stephanie Thomovsky2; Craig Thompson2; Qi Yang1 1Purdue University; 2Veterinary Teaching Hospital, Purdue University Mechanical obstruction accounts for a high failure rate in ventriculoperitoneal shunting. We evaluated the ability of a magnetic microactuator to micronize obstructive hematoma fragments within ventriculoperitoneal shunts. An in vitro hydrocephalus model was used. Phosphate‐buffered saline was continuously driven into a 100 ml beaker representing the cranial vault. In five controls, outflow from the beaker was via a ventricular catheter (VC), valve and distal catheter. Five treatment shunts were identical except the VC contained a microactuator. Porcine blood (85 ml) was added to the beaker and entered the shunts. Hydrodynamic resistance within the beaker was measured. Over a 7‐hour experiment, time over threshold pressure of 40 mm Hg (TOT), peak obstructive pressure and end‐experiment outflow volume were measured. The site of all occlusions was recorded. Four of five control shunts developed 6 obstructions (3 VC; 3 valve and distal catheter) compared to 1 treatment shunt (1 VC). Control shunts demonstrated persistently high pressure (TOT, 293.48 minutes) compared to treatment shunts (TOT, 0.62 minutes) (p = 0.006). Mean peak obstructive pressure was 213.0 mm Hg and 41.1 mm Hg in the control and treatment groups, respectively (p = 0.001). At end‐experiment, significantly larger volumes were collected from treatment than control shunts (p = 0.047), further supporting prolonged patency of treatment shunts. These data suggest that a microactuator is an effective, non‐invasive method for preventing ventriculoperitoneal shunt obstruction. Microactuator‐embedded shunts conferred protection along the entire length of the shunt (VC and VDC), maintaining a pressure <40 mm Hg for the entire experiment duration in 3/5 shunts. ABSTRACT N02 Pharmacokinetics of a novel cytosine arabinoside subcutaneous protocol in dogs with meningoencephalomyelitis of unknown etiology Hilary A. Levitin; Kari Foss; Devon Hague; Jennifer Reinhart; Timothy Fan University of Illinois Meningoencephalomyelitis of unknown etiology (MUE) is a common cause of non‐infectious inflammatory disease of the central nervous system in dogs. It is an important disease in the field of veterinary medicine given the severity of neurological signs that can be seen at the time of diagnosis, its guarded prognosis, and the large financial investment required by owners for diagnostic testing and treatment. Cytosine arabinoside (CA) has become an attractive treatment to be given with corticosteroids as CA is associated with favorable survival times and low incidence of systemic side effects in dogs. Various dosing recommendations exist, most of which indicating inpatient treatment, with no consensus of a standard of care. The purpose of this study was to evaluate the pharmacokinetics of a novel one‐day SC CA protocol in dogs with (MUE). Eight client‐owned dogs that had MRI and CSF findings compatible with antemortem diagnosis of MUE, along with pertinent negative infectious disease testing, were prospectively enrolled in the study. All eight dogs received a standard CA constant rate infusion (CRI) protocol (200 mg/m2 IV over 24 h) as treatment for MUE. Four weeks later, the SC protocol (50 mg/m2 every 2 h for 4 treatments) was administered. Prior to initiating each protocol, a CBC and chemistry were performed to assess for adverse effects. Blood samples were collected 0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, and 24 h after initiating each protocol. Plasma CA concentrations were measured using a validated high‐pressure liquid chromatography assay. Steady state was defined as plasma CA concentrations exceeding 1 μg/mL at 1 and 8 h following initiation of treatment, consistent with previous studies. The Wilcoxon signed rank test was used to compare pharmacokinetic parameters of interest between protocols. No adverse effects were observed in CBC and chemistry panels performed prior to administering each CA protocol. Peak CA concentration (Cmax) for the SC protocol was significantly higher than for the CRI protocol, measuring 3.4 μg/mL (1.6–9.7 μg/mL) and 1.09 μg/mL (0.77–1.67 μg/mL), respectively (p = 0.0156). CA concentration at 1 and 8 h following initiation of treatment was significantly higher for the SC protocol compared to the CRI protocol (p = 0.0078). CA concentrations were above 1 μg/mL for a significantly longer period of time for the SC protocol versus the CRI protocol, measuring 9.25 h (4.5–10.5 h) and 3.125 h (0–9.75 h), respectively (p=0.039). The investigated SC protocol administered over 8 h provided superior CA plasma levels for a longer duration of time than a standard CRI protocol administered over 24 h. Furthermore, the proposed SC protocol is amenable to outpatient treatment, reducing stress associated with hospitalization and limiting repeated IV catheterization. ABSTRACT N03 The bloody study: Effect of hemodilution on cerebrospinal fluid analysis in dogs with neurological disease Rachel Lampe; Anne Barger; Kari Foss; Devon Hague University of Illinois Elevations of total nucleated cell count (TNCC) or total protein (TP) concentration in the cerebrospinal fluid (CSF) of dogs with neurologic disease can help categorize lesions in the central nervous system. Iatrogenic blood contamination at the time of CSF collection is a common occurrence, which can make diagnostic interpretation difficult. The purpose of this study was to identify the best method of correction of TNCC in CSF, based on the amount of hemodilution present. Paired sequential samples of CSF were prospectively obtained from a single collection site and patient in which one sample had visibly more hemodilution than the other. The TP concentration, red blood cell (RBC) count, and TNCC were analyzed within 30 minutes of collection. A complete blood count (CBC) was collected within 24 hours of the CSF collection. Two linear regression models were fitted, and the results were compared with 3 previously suggested correction formulas. Pearson's correlations coefficients were calculated for each correction formula with the difference between the TNCC in the hemodiluted and clear sample. Sum squared errors were compared among the 5 correction formulas. Nineteen paired samples were collected. The differences between the hemodiluted and clear samples were significant for TNCC (p < 0.00042), RBC count (p < 0.0001) and TP (p = 0.0013). Using a ratio of 500:1 and 1000:1, RBC:WBC yielded a correlation of r = 0.78. A previously suggested correction formula that included the WBC and RBC from the CBC yielded a correlation of r = 0.98. Two linear regression models fitted using the CSF TNCC, RBC, and the peripheral blood RBC, with one additionally including the peripheral WBC, both had a correlation of r > 0.99. The linear regression model including both the peripheral RBC and WBC had the lowest sum squared errors. The results of the study indicate that hemodilution has an effect on the TNCC, RBC, and TP in CSF. All correction methods including CBC parameters were more accurate than evaluating the hemodiluted CSF parameters in isolation. A linear regression model including the RBC and WBC from the CBC provided the most accurate correction of TNCC in hemodiluted CSF. ABSTRACT N04 The role of prophylactic omeprazole in dogs treated surgically for thoracolumbar intervertebral disc herniation Jaya M. Mehra 1; Melissa Lewis1; Katie Tolbert2 1Purdue University; 2Texas A&M University Gastrointestinal (GI) signs and bleeding are commonly reported in dogs with thoracolumbar intervertebral disc herniation (TL‐IVDH). Dogs are frequently treated with proton pump inhibitors (e.g., omeprazole) during hospitalization, however, their efficacy in reducing GI signs in these dogs is unknown. We hypothesized that in dogs undergoing surgery for acute TL‐IVDH, omeprazole would not decrease the frequency of GI signs compared to placebo. Client‐owned dogs undergoing hemilaminectomy for acute TL‐IVDH. Randomized double‐blinded placebo‐controlled prospective clinical trial. Placebo or omeprazole (1 mg/kg) was orally administered q 12 h for 5 days during hospitalization. Development of clinical GI signs were recorded daily and fecal occult blood (FOB) testing, PCV, and blood urea nitrogen (BUN)/creatinine ratios were performed at specific time points. A fisher's exact test (p < 0.05) was used to compare the frequency of GI signs or clinicopathologic abnormalities between groups and to investigate an association between pre‐operative anti‐inflammatory drug use and development of clinical GI signs. Twenty‐one dogs (12 group A, 9 group B) were enrolled with mean SD age of 6.5 ± 2.6 years. GI signs developed in 12/21 dogs (57%; 7/12 group A, 5/9 group B) which was not different between groups. Diarrhea was common (38%; 5/12 group A, 3/9 group B), but clinical GI bleeding was rare (9%; 1/12 group A, 1/9 group B). FOB was positive in 7/21 dogs (33%; 3/12 group A, 4/9 group B) and postoperative BUN/creatinine ratio was elevated in 5/21 dogs (24%; 4/12 group A, 1/9 in group B); these differences were not significant between groups. Anti‐inflammatory drugs were used prior to enrollment in 15/21 dogs (71%; 8/12 group A, 7/9 group B) and were not significantly associated with development of GI signs. GI signs were common in dogs undergoing surgery for acute TL‐IVDH. Short‐term, prophylactic omeprazole treatment did not decrease development of GI signs compared to placebo. ABSTRACT N05 What's wrong with rongeuring? Comparing pneumatic burr and rongeuring techniques for thoracolumbar hemilaminectomies Barbara Lindsay Center for Veterinary Specialty and Emergency Care This retrospective study compares the neurological outcomes of small dogs undergoing a thoracolumbar hemilaminectomy for intervertebral disc herniation (IVDH), performed via a standard technique using a pneumatic burr or a rongeuring technique using a combination of Lempert and Kerrison bone rongeurs. The secondary aim was to determine if the surgical time was significantly different between the two techniques. Exclusion criteria included: dogs weighing more than 8 kg, neurological pathology other than IVDH, multiple site non‐continuous hemilaminectomies, and incomplete medical records. An adjusted Modified Frankel Score (MFS) was assigned to each dog prior to surgery, day after surgery, at discharge, and at recheck. Anesthetic records were evaluated to accurately record the surgical time of each procedure (cut to closure of incision). Records of 297 separate surgical procedures were analyzed (2012–2019); 173 were performed with a pneumatic burr and 124 performed with rongeurs. Mean age of dogs who underwent the rongeuring technique were older (6.85 y) compared to the pneumatic burr group (5.96 y). No significant difference was present in the pre‐surgical adjusted MFS between the two groups nor was the length of hospitalization. Neurological scores at each time point for the two surgical groups were analyzed using Mann‐Whitney tests, and no difference was found (all p values <0.05). Surgical time was found to be significantly shorter in the rongeur group (83 minutes), compared to the pneumatic burr group (113 minutes). In conclusion, rongeuring provides a safe surgical alternative in small dogs with IVDH, which may also allow for a shorter anesthetic time. ABSTRACT N06 Pharmacokinetics of mebendazole in canine plasma and cerebrospinal fluid: A pilot study Amy B. Yanke 1; Kendall Day2; Amanda Taylor3; Crisanta Cruz‐Espindola1 ; Christina Hargis1; Dawn Boothe1 1College of Veterinary Medicine, Auburn University; 2College of Veterinary Medicine, University of Florida; 3MedVet Columbus Novel therapies are needed for treatment of gliomas. Fenbendazole and mebendazole demonstrated anti‐neoplastic effects on high grade canine glioma cells at in vitro mean inhibitory concentrations (IC50) of 10 ng/ml for mebendazole versus approximately 150 ng/ml for fenbendazole. Our study aimed to titrate the dose of mebendazole necessary to achieve potentially effective concentrations (10 ng/ml) of mebendazole in cerebrospinal fluid (CSF) when administered orally to dogs. We hypothesized that an oral dose of 100 to 200 mg/kg would be necessary. Beagle cross dogs received 100 mg/kg (n = 4) or 200 mg/kg (n = 5) and blood samples were collected intermittently for 60 hrs. Mebendazole was quantitated in canine plasma and CSF using high performance liquid chromatography (lower limits of quantitation 10 and 5 ng/ml, respectively). Data was subjected to noncompartmental analysis. The mean peak plasma concentrations (Cmax; ng/ml) were, for 100 and 200 mg/kg, respectively, 201 + 88 occurring at 7 + 2 hr and 181 + 80 at 15 + 4.5 hr. The respective areas under the curve (AUC: ng/ml/hr) were 2350 640 vs 3072 + 1502. Average concentrations (ng/ml) were 45 + 8.4 vs 67 + 29. For CSF, Cmax was 11 + 11 vs 20 + 6.1 and AUC 88 + 56 vs 287 + 114. Relative bioavailability in CSF vs plasma was 5 to 10%. No adverse events were noted. This study demonstrates a dose concentration relationship for mebendazole in dogs and that the in vitro IC50 for gliomas can be achieved in CSF at 100 mg/kg, although 200 mg/kg might be more prudent. Optimal target concentrations in CSF for treatment of canine gliomas remains to be determined. ABSTRACT N07 Evaluation of serum high‐mobility group box 1 concentration in dogs with epilepsy Yoonhoi Koo; Taesik Yun; Hakhyun Kim; Ji‐Houn Kang; Mhan‐Pyo Yang; Byeong‐Teck Kang Laboratory of Veterinary Internal Medicine, Veterinary Teaching Hospital, College of Veterinary Medicine, Chungbuk National University Elevation of inflammatory mediators' concentrations in the brain decreases the seizure threshold which contributes to epileptogenesis. High‐mobility group box 1 (HMGB1) is one of the key mediators of neuroinflammation. It has been shown that serum HMGB1 levels increased in laboratory animal models and human patients with epilepsy. However, studies of serum HMGB1 concentrations in epileptic dogs have not been reported. We hypothesized that there would be elevated levels of serum HMGB1 in dogs with epilepsy and that HMGB1 levels may vary according to the epilepsy etiology, epilepsy status, and treatment. Blood samples were collected from 28 epileptic dogs, 12 dogs with non‐epileptic brain disease, and 26 healthy dogs. Meningoencephalitis of unknown etiology and brain tumors without seizure were referred to as non‐epileptic brain diseases. Epilepsy dogs were divided into idiopathic epilepsy (14 dogs) and structural epilepsy (14 dogs). Serum HMGB1 concentrations were estimated using the canine HMGB1 enzyme‐link immunosorbent assay kit. Dogs with epilepsy regardless of underlying causes had significantly higher serum HMGB1 levels than healthy dogs (p = 0.001). Dogs with structural epilepsy had significantly higher serum HMGB1 levels than healthy dogs (p = 0.003), however, dogs with non‐epileptic brain disease did not. Moreover, serum HMGB1 concentrations of idiopathic epilepsy with epilepsy course >3 months were increased compared to with epilepsy course ≤3 months (p = 0.019). However, serum HMGB1 concentration was not correlated with seizure frequency, brain lesion volume, seizure control status and duration of treatment. Serum HMGB1 concentrations of epilepsy dogs were significantly higher than healthy dogs, however dogs with non‐epilepsy did not, indicating that serum HMGB1 could be a biomarker of epileptic dogs. Furthermore, the elevation of serum HMGB1 concentration in epileptic dogs was found to be independent of seizure frequency, brain lesion volume, seizure control status, and duration of treatment. These results suggest that serum HMGB1 could be used as an early diagnostic biomarker for epilepsy in dogs. ABSTRACT N08 Cannabidiol disposition after single oral dosing in fasted and fed dogs Dawn M. Boothe 1; C. Cruz‐Espindola1 ; R. Gillette2; R. Strunk1; C. Warner2 1Auburn University; 2Travco Products Inc Cannabidiol (CBD), one of two major phytocannabinoids, is largely void of psychotropic effects. Increasingly it is being used for a variety of canine conditions. Orally administered CBD undergoes first pass metabolism, leading to approaches that increase oral bioavailability (F). The purpose of this study was to determine if oral bioavailability of a full spectrum hemp oil (NMXCB1220™) can be improved in dogs when administered as a soft chew, or, as in humans, with food. Normal, apparently healthy beagle dogs (n = 8) were studied three times using a non‐randomized triple cross‐over design with a 7‐day washout. CBD (2 mg/kg) was administered orally as hemp‐oil in fasted, followed by fed dogs and finally as a soft chew. Blood was collected intermittently for 24 hrs. Plasma CBD and THC were quantitated using LC‐MS/MS with MRM (validated in dogs). Following noncompartmental analysis, key parameters were (mean + sd, fasted oil followed by fed oil and fasted soft chew): maximum plasma concentration (Cmax; ng/ml) 110 + 61 vs 289 + 127 vs 272 + 130 at time to maximum concentration (hr) of 3.5 + 1.4 vs 2.3 + 0.7 vs 3.8 + 0.7; area under the curve (ng/ml/hr) 1672 + 2543 vs 1292 + 592 vs 1100 + 379; and elimination half‐life (hr) of 6.4 + 3.3 vs 6.3 + 1.7 vs 5.0 + 2. The relative bioavailability (F) of CBD in fed vs fasted animals was 1.78 + 0.89 and fed hemp oil vs fasted soft chews 1 + 0.3. THC was detectable in all preparations (Cmax <30 mcg/ml). Feeding increased hemp oil CBD bioavailability in dogs in this study. Fasted dogs receiving a soft chew had similar concentrations to that achieved with industrial hemp oil in fed dogs.   ABSTRACT N09 The use of magnetic resonance spectroscopy to differentiate canine brain masses Sarah B. Deluty 1; Lynn Griffin2; Rebecca Packer2 1CVM, Colorado State University; 2Colorado State University Magnetic Resonance Imaging (MRI) is a common modality used to aid in the diagnosis of canine brain tumors; however, limitations remain for accurate determination of mass lesion type. MR spectroscopy (MRS) can be obtained with the diagnostic MRI procedure, and is a quantitative measure of brain metabolism that may eventually provide information to help predict histologic type, grade, outcome, and individualized treatment targets. The aim of this study was to evaluate the use of MRS in the context of canine brain masses, and evaluate whether or not MRS could be used to differentiate neoplastic from non‐neoplastic masses, as well as differentiate histologic type of tumor. Data from 144 clinical cases of naturally‐occurring canine brain tumors and inflammatory lesions that presented to the Colorado State University Veterinary Teaching Hospital from 2006–2019 were available for analyses. 44 of these cases provided met the inclusion criteria for paired MR spectroscopy and histological data for correlative study. Choline (Ch), creatine (Cr), lactate (LL), myoinositol (mI) and NAA brain metabolites, and calculated values of Cr+Ch, Ch/Cr, Cr/Ch, NAA/Cr, NAA/Ch, Cr/NAA and Ch/NAA, were explored for their correlation to the final etiology of brain dysfunction. NAA/Ch differed significantly between normal brain versus glioma (p = 0.0082), and glioma versus inflammatory lesions (p = 0.0118). Based on our data, MRS may be used as additional evidence to differentiate glioma from inflammatory brain lesions, providing and alternative non‐invasive diagnostic tool to clinicians. ABSTRACT N10 Magnetic micro‐actuator enabled catheters for ventriculoperitoneal shunting: Magnetic resonance safety and artifacts R. Timothy Bentley 1; Angel Enriquez2; Hyowon Lee2; Tiffany Lyle2 1Veterinary Clinical Sciences, Purdue University; 2Purdue University Our previous micro‐actuator studies have shown reduction of ventriculo‐peritoneal shunt obstruction in vitro and in vivo. Magnetic resonance imaging (MRI) safety and artifacts still need characterization, including gradient echo sequences which are extreme conditions for magnetic implants. Ventricular catheters were implanted into the lateral ventricles of four pigs (2 control, 2 micro‐actuator). MRI was performed post‐operatively and one month later. After neurological observation for one month, pigs were sacrificed for gross and histological evaluation. All pigs returned to neurologically normal post‐operatively, except contralateral menace response deficits. MRI revealed no evidence of micro‐actuators induced mechanical or thermal injury, with no signal changes in adjacent brain parenchyma. Minor post‐operative MRI findings, including contrast‐enhancement limited to the surgical site, were the same in both groups and resolved at one month. Ventriculomegaly was mild in both groups. Micro‐actuator associated artifacts unchanged at one month included striking large, 4‐lobed signal voids on gradient echo sequences. Small, mainly hypointense artifacts were present on T1‐weighted, T2‐weighted, and fluid attenuation inversion recovery sequences. Grossly, maximal ventricular dimension was 1–1.5 cm in both groups. Flocculent material remained in the ventricle of 2 treatment and 1 control pig. The implant tract was associated with gliosis or inflammatory infiltrates in all 4 pigs. There is apparent safety upon MRI of micro‐actuator enabled ventricular catheters, with no clinical, imaging or pathological differences from the control group. MRI micro‐actuator artifacts overlapped in appearance with surgical hemorrhage, except a characteristic, 4‐lobed gradient echo appearance. ABSTRACT N11 Evaluation of “underreporting of seizures” with electroencephalography (EEG) in canine epilepsy Masayasu Ukai 1; Thomas Parmentier1; Miguel Cortez2; Andrea Fischer3; Luis Gaitero1; Hannes Lohi4; Stephanie Nykamp1; Tarja Pääkkönen4; Veronique Sammut5; Fiona James1 1Ontario Veterinary College, University of Guelph; 2The Hospital for Sick Children (SickKids); 3LMU Munich; 4University of Helsinki; 5VCA West Los Angeles Animal Hospital Background: In people, objective data from electroencephalography (EEG) are mainly used to diagnose epilepsy, measure seizure frequency and evaluate efficacy of anti‐seizure drugs. Conversely, many epilepsy studies in veterinary neurology use subjective data, e.g., owner‐based questionnaires or histories. The possibility of underreporting of seizures using only subjective data, similar to the phenomenon known in human medicine, is unknown in veterinary epileptology. Hypothesis/Objective: This study examined the correlation between reported seizure frequency and EEG frequency of ictal paroxysmal discharges (PDs) to determine whether the seizure underreporting phenomenon exists in veterinary epileptology. Animals: Thirty‐three ambulatory EEG recordings in epileptic dogs that showed more than one ictal PDs. Dogs with status epilepticus were excluded. Methods: Retrospective observational study. Ictal PDs were manually counted over the length of recording to obtain the frequency of EEG seizures. Reported seizure frequency from owners was categorized into four groups indicating weekly, daily, hourly and minutely seizure. Spearman rank test was used for correlation analysis. Results: The coefficient value (rs) comparing reported seizure and ictal PD frequency is 0.368. Other rs comparing history against various seizure types are: 0.296 for all types without myoclonic epilepsy, 0.206 for myoclonic epilepsy, and 0.374 for absence seizures. Conclusions: Only a weak correlation exists between frequency of reported seizure from caretakers (subjective data) and ictal PDs on EEG (objective data). Subjective data may not be reliable enough to determine true seizure frequency given the discrepancy with EEG‐confirmed seizure frequency. Confirmation by prospective study would be ideal. ABSTRACT N12 Juvenile‐onset motor polyneuropathy in Siberian cats Melissa Lewis 1; Kelly Crawford2; Dayna Dreger1; Kari Ekenstedt1 1Purdue University; 2Med Vet Polyneuropathies are infrequently described in cats, with a subset exhibiting genetic predisposition as reported in several specific breeds. Our objective was to characterize a novel motor polyneuropathy in a family of related Siberian cats. Clinical data and pedigree information were obtained from the medical records and breeder of eight closely related Siberian cats including four clinically affected and four clinically unaffected individuals. Electrodiagnostic and muscle/nerve biopsy samples were obtained from one affected cat. Follow‐up information was obtained for all affected cats including any relapses and treatments administered. Onset of signs ranged from four to ten months in affected cats. Clinical signs were characterized by progressive or waxing/waning neuromuscular weakness (4/4), normal sensory function (4/4), and variably decreased withdrawal reflexes (3/4) and plantigrade stance (2/4). All cats returned to normal neurologic function within several weeks; two cats had a recurrence of weakness within a month of initial signs from which they recovered fully. In one cat, electromyography and motor nerve conduction studies showed multicentric, distally distributed spontaneous activity, normal conduction velocity, reduced amplitude, and polyphasia. Histologic evaluation of muscle and nerve biopsies in that cat showed recent denervation and intraneural edema. All cats were treated with robenacoxib with two subsequently switched to tapering courses of prednisolone. Pedigree analysis of the affected family supports an autosomal recessive, single‐gene mode of inheritance, although a genetically complex/polygenic condition cannot be ruled‐out. Further genetic investigations are underway. We describe a novel motor polyneuropathy in juvenile Siberian cats characterized by self‐limiting weakness with potential relapse. ABSTRACT N13 Relationship between admission variables in dogs with brain herniation: A retrospective study in 54 dogs Jiwoong Her 1; Katherine Gerken2; Erik Hofmeister2; Amy Yanke2; Ashley Peters3; Jin Yoon4; Lenore Bacek5; Kendon Kuo2 1Department of Clinical Sciences, College of Veterinary Medicine, Auburn University; 2College of Veterinary Medicine, Auburn University; 3Veterinary Emergency Group; 4Veterinary Surgical Centers; 5BluePearl Veterinary Partners Brain herniation is one of the most frequent life‐threatening neurological emergencies. This study aimed to document the admission systolic blood pressure (SBP), heart rate (HR), and Modified Glasgow Coma Scale (MGCS) in dogs with or without brain herniation and to determine the correlation with brain herniation, to provide a specific indicator for brain herniation in the emergency setting. Medical records from one hospital were compiled to identify dogs presenting for neurological signs with a brain MRI. Based on MRI findings, dogs were divided into two groups: dogs with evidence of herniation or with a normal brain MRI (control group). The two groups were compared for HR, SBP, MGCS, SBP‐HR, age, and weight. A total of 54 dogs with brain herniation were included. The control population consisted of 40 dogs. The herniation group had significantly higher SBP (p = 0.0078), greater SBP‐HR difference (p = 0.0006), and lower MGCS (p < 0.0001) compared to control group. A cut‐off value of SBP >178 mm Hg, SBP‐HR >60, and MGCS <14 provide a specificity of 90 to 98 percent to identify brain herniation. A combination of SBP >140 and HR <80 provided 24% sensitivity and 100% specificity to diagnose dogs with brain herniation (p < 0.0001). High SBP, a greater SBP‐HR, a combination of higher SBP and lower HR, and low MGCS upon admission were associated with brain herniation in dogs with neurological signs. Early recognition of these abnormalities may help veterinarians to suspect brain herniation and determine timely treatment.   Abstract: N14 Serum and cerebrospinal fluid GFAP and pNF‐H concentrations in dogs with meningoencephalomyelitis of unknown etiology Lauren Green; Christopher Mariani; Laura Ruterbories; Natasha Olby; Peter Early; Karen Munana North Carolina State University Veterinary Hospital Meningoencephalomyelitis of unknown etiology (MUE) is a common cause of neurologic dysfunction in dogs. Despite treatment, approximately 33% of dogs do not survive longer than three days. No consistent factors have been identified that predict prognosis. Glial fibrillary acidic protein (GFAP) and phosphorylated neurofilament heavy chain (pNF‐H) are structural proteins found within astrocytes and neurons, respectively, and are released into the cerebrospinal fluid (CSF) and blood when these cells are damaged. We hypothesized that these proteins might be useful biomarkers of prognosis in dogs with MUE. The objectives of this study were to compare CSF and serum concentrations of GFAP and pNF‐H from dogs with MUE to samples from clinically normal dogs and to investigate the ability of these biomarkers to predict survival to hospital discharge. Serum and CSF samples from dogs diagnosed with MUE (n = 13 and 40) and clinically normal dogs (n = 5 and 10) were retrieved from a biorespository. Concentrations of GFAP and pNF‐H were determined using commercially available ELISA kits. There were no clinically relevant differences in serum concentrations of either analyte between groups. CSF concentrations of GFAP and pNF‐H were increased in MUE dogs compared to control dogs (p = 0.0071 and p < 0.0001, respectively). No differences were noted in GFAP (p = 0.183) or pNF‐H (p = 0.773) when comparing dogs that failed to survive to discharge versus dogs that survived. CSF, GFAP and pNF‐H may be useful biomarkers of MUE, although this study did not support a role in predicting survival. ABSTRACT N15 Comparing baseline T‐cell activation, by IL‐2 expression, between dogs with immune‐meditated diseases and healthy dogs Alison Little; Caitlin Riggs; Michaela Beasley; Santosh Katarukonda; Andy Shores; Andrew Mackin; Robert Wills; Henrique Lupiano; Todd Archer Mississippi State College of Veterinary Medicine Cyclosporine is commonly utilized for the treatment of immune‐mediated diseases. Although pharmacokinetic monitoring of this drug is widely available, cyclosporine blood concentrations may poorly reflect clinical response in dogs. Human studies have found that pharmacodynamic testing of patients receiving cyclosporine may be preferable. Based on advances in human cyclosporine monitoring, a PCR‐based assay measuring RNA expression of IL‐2 in activated T cells has been developed and validated in dogs by the Mississippi State Pharmacodynamic Laboratory. We hypothesize that dogs with immune‐mediated diseases will have a higher baseline level of IL‐2 expression compared to healthy control dogs, due to an overactive immune system in the disease state. The purpose of this study was to compare the degree of baseline (pre‐treatment) T‐cell activation, as calculated by the difference between unactivated and activated delta Ct IL‐2 expression, between healthy dogs and dogs with meningoencephalitis of unknown origin (MUO), inflammatory bowel disease (IBD), immune‐mediated hemolytic anemia (IMHA). Three mLs of blood were collected from healthy dogs (9), as well as dogs definitively diagnosed with MUO (8), IBD (9) and IMHA (9) prior to treatment with cyclosporine. Blood was submitted to the Mississippi State Pharmacodynamic Laboratory for baseline RT‐qPCR analysis of IL‐2 mRNA expression. A linear model determined the least square mean for the difference in unactivated and activated IL‐2 dCt was higher in the diseased states (7.122 for IMHA, 7.573 for IBD, 9.419 for MUO) as compared to the healthy dogs (5.279), with a higher number signifying more activation. Differences in least squares means with Tukey adjustment for multiple comparisons determined that dogs with MUO and IBD had significantly higher values than healthy dogs. Dogs with IMHA had higher values than healthy dogs but a significant difference was not detected. No significant differences in values were detected between the three disease states. The baseline degree of activation of T cells was higher in disease states as compared to healthy dogs, likely due to the overactive immune system in these immune‐mediated diseases. While it has recently been shown that healthy dogs demonstrate significant suppression of IL‐2 expression within 24 hours of oral dosing with cyclosporine, in our experience dogs with immune‐mediated disorders often do not respond that quickly. An increased degree of T‐cell activation in disease states, as compared to healthy dogs, may be one possible explanation for the additional time it appears to take for a clinically relevant response to occur in patients with immune‐mediated disorders. ABSTRACT N16 Potential use of dry surface electrodes for electroencephalography (EEG) in dogs Michal Hazenfratz; Shane Bateman; Luis Gaitero; Fiona James; Julia Luca; Thomas Parmentier University of Guelph Electroencephalography (EEG) records the cerebral cortical electrical activity via scalp electrodes. A common type of electrode is the subdermal wire electrode (SWE) for which sedation is frequently required for placement due to its mild invasiveness. Surface electrodes such as spring‐loaded (SLE) and PressOn (POE) electrodes are less invasive but have never been evaluated in dogs. We hypothesized that the dry surface electrodes would remain functional and perform equivalently to the SWEs. EEG was recorded on 6 awake dogs over 6 hours. Surface electrodes were randomized to one of 8 locations above an SWE, creating 4 POE‐SWE and 4 SLW‐SWE comparison pairs. Epochs were selected throughout the recordings and loss of electrode signal, electrode impedance, as well as concordance with spectral analysis, were compared between electrode types. After the first hour, SLE vs. SWE retention was 15/24 vs. 24/24 (p‐value = 0.003) and POE to SWE was 21/24 to 24/24 (p‐value = 0.233). After 6 hours, SLE vs. SWE retention was 12/24 vs. 23/24 (p‐value = 0.001162) and POE to SWE was 15/24 vs. 20/24 (p‐value = 0.1939). Impedance was significantly higher for both SLE and POE compared with SWE (p‐value < 0.001). Preliminary concordance for spectral analysis showed insufficient agreement between the two types of surface electrodes and the SWEs. SWE consistently outperformed the novel dry surface electrodes, but the POE may have potential for clinical use. ABSTRACT N17 Evaluation of three‐dimensional printing and virtual rendering as teaching tools for cerebrospinal fluid collection Megan Lin 1; Leontine Benedicenti2; Amy Thibault2; Kenneth Drobatz2 1Red Bank Veterinary Hospital; 2School of Veterinary Medicine, University of Pennsylvania The use of three‐dimensional (3D) models and virtual rendering are becoming more common in veterinary medical education. In this prospective study, a novel 3D‐printed model of a canine skull with its C1 and C2 vertebrae, and a 3D virtual rendered video were created to teach students about the anatomy and procedure of a cerebrospinal fluid (CSF) collection. The goals of this study were to: (1) compare the effects of three teaching methods (text reading, video of clinical demonstration, 3D virtual rendered video) on successful outcomes of students performing a CSF collection on a physical 3D‐printed model, and (2) evaluate students' learning satisfaction from using the 3D‐printed model. This study was conducted on 56 fourth‐year veterinary students enrolled in the Penn Vet Neurology service clinical rotation from 2019–2020. Students were randomly divided into three groups: (1) reading a text description with a 2D image (19 students), (2) watching a clinical video of a neurologist performing CSF collection on a dog with voice‐over of the text description (19 students), (3) watching a 3D virtual rendered video with voice‐over of the text description (18 students). After studying their teaching method for 5 minutes, students were given 3 attempts to perform CSF collection on the 3D‐printed model. Students were evaluated on palpation of correct anatomical landmarks on the model and a CSF collection outcome was recorded as successful if fluid was obtained from the model. The Fisher's exact test with pairwise comparisons was used to determine significant differences in outcomes between the three groups. When comparing students' success rates of correct anatomical landmark palpation on the 3D‐printed model, there was no significant difference between the 3D virtual rendered video and text groups (p = 0.180), or between the text and clinical video groups (p = 1.000). However, there was significant difference between the clinical video and 3D virtual rendered video groups (p < 0.046), demonstrating that the clinical video method was more effective for students to achieve correct anatomical landmark palpation. When comparing students' success in CSF collection outcomes on the 3D‐printed model, there was no significant difference between all three groups in success of obtaining fluid on the first attempt, second attempt, third attempt, or overall success of all three attempts combined (p > 0.05 for all comparisons). Following the study, students ranked their level of satisfaction regarding if using the 3D‐printed model was helpful for learning about the CSF collection procedure (scale from 1–5, 1 being not helpful, 5 being very helpful). Results were collected from 54 of the 56 total students (96%), with a mean rating of 4.037. Students in the 3D virtual rendered video group were also asked to rank if having 3D virtual rendering shown in lectures would be helpful (same scale as previous). Results were collected from 17 of the 18 students (94%), with a mean rating of 4.58. These results suggest that while students have high learning satisfaction with the use of 3D models and virtual rendering, further research is required to evaluate the true benefits and correlation of 3D tools on students' learning outcomes when compared to traditional teaching methods. ABSTRACT N18 Aging dogs with spontaneous brain microhemorrhages have diminished interthalamic adhesion size: A comparative MRI study Curtis W. Dewey 1; Emma Davies1; Philippa Johnson1; Marissa O'Donnell2; Simon Platt3; Mark Rishniw1; Kelsey Robinson3; Joseph Sackman2 1College of Veterinary Medicine, Cornell University; 2Long Island Veterinary Specialists; 3College of Veterinary Medicine, University of Georgia Spontaneous brain microhemorrhages (SBM) in elderly people occur with Alzheimer's disease but also occur in the absence of dementia. A common cause of SBMs in people is cerebral amyloid angiopathy (CAA), which is associated with brain atrophy. CAA patients often present for transient neurologic dysfunction. Brain microhemorrhages have been described in older dogs; it is unclear if these are associated with brain atrophy. Small interthalamic adhesion (IA) size on MRI is a reliable indicator of brain atrophy in canine cognitive dysfunction (CCD). We hypothesized that aging dogs with SBM (based on T2*) presenting for neurologic dysfunction but without cognitive decline would have small IA sizes compared with successfully aging dogs. The objective of this study was to compare IA size between 3 groups of aging (>9 yrs) dogs: (1) neurologically impaired dogs with SBM but without cognitive dysfunction (17) (2) dogs with CCD (16) and (3) successfully aging dogs (controls‐26). Common clinical complaints for SBM dogs was recent onset of central vestibular dysfunction, seizures, or both. MR images from 59 dogs were reviewed. IA (height and mid‐sagittal area) and total brain volume (TBV) measurements were acquired. IA measurements, normalized to TBV were compared between groups. Controls had significantly larger IA measurements and normalized IA area than SBM and CCD dogs, but these did not differ between SBM and CCD. CCD patients had fewer microhemorrhages than SBM dogs (p < 0.05). SBMs in aging dogs is associated with brain atrophy like CCD, but may represent a distinct disease category. ABSTRACT N19 Canine cognitive dysfunction patients have reduced hippocampal volumes compared with aging controls: An MRI study Curtis W. Dewey 1; Marissa O'Donnell2; Simon Platt3; Mark Rishniw1; Kelsey Robinson3; Joseph Sackman2 1College of Veterinary Medicine, Cornell University; 2Long Island Veterinary Specialists; 3College of Veterinary Medicine, University of Georgia Hippocampal atrophy is a key pathologic and MRI feature of human Alzheimer's disease (AD). Hippocampal atrophy has not been documented via MRI in canine cognitive dysfunction (CCD), which is considered the dog model of human AD. The purpose of this retrospective comparative volumetric MRI study was to compare total hippocampal volumes between successfully aging (control) dogs and dogs diagnosed with CCD. Mimics® software was used to derive total hippocampal volumes and total brain volumes from the MRI studies of 42 aging dogs (>9 yrs): 16 dogs diagnosed with CCD and 26 successfully aging controls. Total hippocampal volume normalized to total brain volume was significantly less for CCD patients compared with control dogs (p < 0.05). The results of this study suggest that‐similar to human AD‐hippocampal atrophy is a pathological feature of CCD. This finding has potential importance for both investigating disease mechanisms related to dementia as well as future hippocampal‐targeted therapies. ABSTRACT N20 Molecular insights into protein aggregation of mutant superoxide dismutase 1 in degenerative myelopathy Shintaro Kimura 1; Ryo Honda1; Yuji O. Kamatari1; Zenichiro Kato1; Hideaki Hara2; Sadatoshi Maeda1; Hiroaki Kamishina1 1Gifu University; 2Gifu Pharmaceutical University In this study, we focused on a canine neurodegenerative disease (degenerative myelopathy: DM) associated with mutant superoxide dismutase1 (SOD1). Several studies have reported that both T18S and E40K mutations in SOD1 promoted the formation of insoluble aggregates in neurons and glial cells. However, the molecular mechanism of the protein aggregation remains unknown. The objective of this study was to clarify the aggregation mechanism of mutant SOD1 proteins (T18S, E40K). Wild‐type (WT) and mutant (T18S, E40K) recombinant canine SOD1 proteins were expressed in Escherichia coli and inactive (apo) and active (holo) types were purified. The aggregate formation was measured over time using Thioflavin‐T (Th‐T) assay. Transmission electron microscopy (TEM) was performed using JEM‐2100F. Further, the denaturation midpoint (Tm) was calculated from the denaturation curve obtained by circular dichroism spectrum measurement under heating. Th‐T fluorescence intensity was significantly increased in apo‐T18S and apo‐E40K SOD1 compared to WT and corresponding holo‐SOD1, respectively. Curvy fibrous aggregates were observed both in apo‐T18S and apo‐E40K SOD1 by negatively stained TEM. There were no aggregates in WT or holo‐SOD1. The Tm values of apo‐SOD1 were ≈ 30°C lower than those of holo‐SOD1, whereas no significant difference was found between WT and E40K. The T18S mutation significantly reduced the Tm value by ≈ 5°C both in the apo‐ and holo‐SOD1. The apo‐SOD1, but not holo‐SOD1, had low Tm values and a high propensity to aggregate, indicating that the unstable apo‐form might be the initial intermediate in SOD1 aggregation. The T18S mutation reduced the structural stability of SOD1. However, the E40K mutation did not alter the thermal stability of SOD1. The E40K mutation decreased the negative net charge which enhances intermolecular electrostatic forces between unfolded polypeptides compared to WT and T18S. In conclusion, we clarified that the T18S and E40K mutation promoted SOD1 aggregation through distinct mechanisms, involving destabilization of the native structure or reduction of the repulsive negative charge, respectively. ABSTRACT N21 Prion‐like propagation of mutant superoxide dismutase‐1 in canine degenerative myelopathy Nana Tanaka; Hiroaki Kamishina; Sadatoshi Maeda; Masatoshi Inden; Yuji Kamatari; Shintaro Kimura Gifu University Canine degenerative myelopathy (DM) is a chronic, progressive and fatal neurodegenerative disease. DM‐affected dogs have homozygous mutations in the superoxide dismutase 1 (SOD1) gene. The accumulation of misfolded protein aggregates in motor neurons is implicated as an important pathological process of DM. However, the mechanism of SOD1 protein aggregation and accumulation is largely unknown. In recent studies, it has been reported that cell‐to‐cell transmission of misfolded protein aggregates in SOD1‐mediated amyotrophic lateral sclerosis (ALS) in humans. In the present study, we investigated the propagation of SOD1 protein aggregates in DM using canine SOD1 expressing cells. Wild‐type (WT) and mutant (E40K) canine SOD1 genes tagged with GFP or DsRed were co‐transfected into mouse neuroblastoma cells. The intracellular SOD1 aggregate formation rate was calculated under a fluorescence microscope. The surfactant soluble and insoluble fractions were extracted from transfected cells, and the relative amount of protein in each fraction was quantified by Western blotting. In addition, cells transfected with WT and E40K plasmids labeled with different fluorophores were co‐cultured and the localization and morphology of each protein were evaluated. Further, E40K‐SOD1 protein aggregates prepared using dithiothreitol was added to the culture medium of WT transfected cells. The aggregate formation rate in the cells was calculated as above. The percentage of cells containing aggregates was markedly higher in WT which were co‐transfected with E40K than that in WT co‐transfected with WT. The relative amount of WT insoluble fraction protein was increased by co‐transfection with E40K. In co‐culture of WT and E40K transfected cells, WT and E40K proteins were co‐localized within the same cells and formed aggregates. Further, the aggregate formation rate of WT was increased by addition of E40K aggregates. Canine mutant SOD1 protein E40K not only undergoes aggregate formation but also induces aggregation of native SOD1 protein. Additionally, it was suggested that E40K aggregates could be taken up into cells and induce aggregate formation of native‐fold proteins. ABSTRACT N22 3D‐printed drill guides for canine thoracic spinal surgery Christopher L. Mariani 1; Ola Harrysson2; Josh Zlotnick2 1College of Veterinary Medicine, North Carolina State University; 2North Carolina State University Various conditions require surgical stabilization of the canine thoracic vertebral column. However, placement of implants into these vertebrae, particularly those cranial to T12, is challenging due to narrow implantation corridors and proximity to critical structures including the spinal cord, aorta and thoracic cavity. We hypothesized that 3D‐printed guides could successfully constrain drill trajectories in these vertebrae to safe, predetermined implantation corridors. Five canine cadavers were obtained and the thoracic vertebral columns were disarticulated, leaving the paraspinal musculature intact. The vertebral segments were imaged with computed tomography and the resulting studies were imported into Mimics (Materialise). The thoracic vertebrae from T8‐13 were individually segmented and 3D objects were created and exported into 3Matic (Materialise). Drill guides were printed on a Projet MJP 2500 Plus (3D Systems) using Visijet M2 Rigid White material. The cadaveric vertebral segments were positioned to approximate a dog in ventral recumbency and a simulated surgical approach was made. The guides were placed and drill tracts were created using a surgical drill with a 2.7 mm drill bit. The vertebral columns were then re‐imaged and imported into Mimics. Accuracy of the intervention was assessed by measuring deviation from the intended entry point as a linear measurement and angular deviation in 3 planes. A total of 58 drill tracts were created in 30 vertebrae. The overall mean entry point deviation was 1.4 mm (range 0.4–3.4 mm) and the overall mean angular deviation was 5.1° (range 1.5–10.8°). This additive manufacturing technique results in drill tracts with accuracy acceptable for clinical use. ABSTRACT N23 Prevalence of radiculopathies associated with type 1 intervertebral disc disease on MRI in dogs Solene Diop 1; Isabelle Masseau2; Joane Parent2 1Highcroft Veterinary Referrals; 2Faculté de Médecine Vétérinaire, Université de Montréal Hansen type I intervertebral disc disease (IVDD) is common in dogs, affecting predominantly chondrodystrophic breeds. Extruded nucleus pulposus in the vertebral canal or intervertebral foramen can induce the onset of radiculopathies by direct compression of the nerve roots. Interestingly, radiculopathies in humans have been reported even in the absence of a compressive component, hypothetically from local inflammation induced by the presence of nearby extruded disc material. The aims of this study were (1) to determine the prevalence of radiculopathies, with or without nerve root compression, using magnetic resonance imaging (MRI) in dogs with type I IVDD, and (2) to investigate a possible association between nerve root anomaly detected on MRI and signalment or clinical data. Medical record database was searched for any dog diagnosed with type 1 IVDD on MRI between January 2009 and March 2019. Studies were included upon availability of T1 weighted post‐gadolinium images. Each imaging study was reviewed for evidence of radiculopathy based on the identification of one or more of the following imaging features: (1) visible compression of the nerve root by extruded material, (2) thickening of the nerve root (in comparison to the contralateral nerve root) or (3) nerve root enhancement on post contrast T1 weighted sequences. Dogs without MRI features of radiculopathy were assigned to the control group. Thirty‐one dogs met the inclusion criteria. Nerve root lesions were identified in 17 dogs (radiculopathy group). Fourteen dogs were included in the control group. Twelve dogs with radiculopathies had a compressive component. For a majority of dogs in the radiculopathy group, the extrusion was lumbar or lumbo‐sacral (L4‐L6: 6/17, L7‐S1:3/17); the extrusion was thoracolumbar (T3‐L3) for only 3 cases, cervical (C1‐C5) for 2 cases and centered on the cervical intumescence (C6‐T2) for 3 cases. Of the 5 dogs without compressive component, radiculopathies were diagnosed based on unilateral thickening of the nerve root (n = 2), nerve root enhancement (n = 1), and for 2 cases, both nerve root enhancement and thickening (n = 2). There was no association between the presence of radiculopathy and the degree of spinal cord compression (p = 0.18) or with any of the demographic data). Dogs with radiculopathies were presented later after the onset of clinical signs than dogs without nerve root lesions (p = 0.03). Radiculopathies with or without nerve root compression can be identified on MRI in dogs with type I IVDD. Their diagnosis relies heavily on acquisition of post contrast images. Standardization of MRI protocols with sequences suited for detection of radiculopathy may contribute to a better recognition and thereafter, a more thorough understanding of their potential contribution to the clinical signs, for example pain. ABSTRACT N24 Impact of von Willebrand factor on dogs with Hansen type 1 disc extrusions Danny Sack; Sarah Stephan; Curtis Dewey; Emma Davies Cornell University This study describes the clinical impacts of von Willebrand factor (VWF) deficiency and outcome of two dogs with Hansen Type 1 disc extrusion. Two otherwise healthy Doberman Pinschers with disc extrusions had extensive bleeding within the vertebral canal secondary to previously undiagnosed VWF deficiency. Hematology, biochemistry, VWF and MRI were performed in both dogs. One dog underwent surgical decompression and both outcomes are described. Both dogs had progressive T3‐S3 myelopathies (one non‐ambulatory paraparetic, one paraplegic with no pain sensation). T2* sequences identified hemorrhage extending the length of 8 to 11 vertebral bodies in both dogs, leading to extensive compression of the spinal cord. Both were VWF deficient (AG of 25 and 40), resulting in a more extensive and compressive spinal cord lesion than typical even in hemorrhagic disc extrusions. One dog received surgical decompression with preoperative cryoprecipitate and desmopressin acetate and improved post operatively recovering normal ambulation after 6 weeks. The deep pain negative dog was euthanized. VWF deficiency resulted in greater extent and degree of compression with rapid ongoing progression. Prompt surgical intervention and a larger surgical site than typical in other hemorrhagic disc extrusions appear critical factors in outcome. Surgical decompression may not be feasible in some dogs due to extension of lesion and concerns for stability. Neither dog had a previous VWF test, with one dog previously spayed. After hour testing for VWF is not available and mucosal bleeding time is not specific. Standardized testing of young dogs from predisposed breeds is recommended prior to emergency situations. ABSTRACT N25 Development of a non‐invasive diagnostic technique to assess neuromuscular disease Rell L. Parker 1; Chelsea Crowe1; Marguerite Knipe1; Adrian Harrison2; Peter Dickinson1 1University of California, Davis; 2University of Copenhagen Needle recorded and stimulated compound muscle action potentials acquired under general anesthesia are standard practice for the assessment of motor nerve conduction and neuromuscular transmission in dogs. Requirement for general anesthesia is limiting for initial diagnosis and serial assessment of disease progression and therapeutic monitoring. We hypothesized that acoustic myography (AMG), with surface recording of muscle pressure waves following surface stimulation of a motor nerve, is feasible for the assessment of motor nerve latency values and repetitive nerve stimulation in anesthetized and non‐anesthetized dogs. Standard needle electrode electrophysiological assessment of motor nerve conduction velocity and repetitive nerve stimulation was done in 4 anesthetized laboratory‐bred beagle dogs (aged 13–16 months) with stimulation of the fibular nerve at the level of the hock, stifle and hip and recording over the fibularis brevis or tibialis cranialis muscles. AMG recordings using a piezoelectric AMG device (CURO‐Diagnostics ApS, Bagsværd, Denmark) were then acquired using needle electrode or skin surface stimulation at the same locations. Latency and repetitive stimulation recordings were generated in 8 pelvic limbs from 4 beagles. Stimulation amplitude was between 2.5–25 mA for surface stimulation, compared to 0.8–5.3 mA for needle stimulation. Stimulation was well tolerated in non‐anesthetized subjects. Repetitive stimulation was performed at frequencies from 1–50 Hz. Correlation of standard needle electrode derived latencies and repetitive stimulation potentials was influenced by temporal sampling limitations of the CURO unit (2 kHz). AMG recording from the fibularis brevis muscle was limited by muscle volume and vascular pulse artifacts. Surface stimulated AMG recordings in non‐anesthetized and anesthetized animals is feasible to measure latency and repetitive nerve stimulation. Modification of the recording device to increase the sampling rate (10 kHz) and establishment of reference range data will be necessary for clinical application. Pilot data from clinical patients has demonstrated the potential utility of AMG in defining neuromuscular junction fatigue in non‐anesthetized dogs with myasthenia gravis. ABSTRACT N26 Correlation between canine cognitive dysfunction clinical metrology instruments, cognitive testing and plasma neurofilament light concentrations Wojciech K. Panek 1; Margaret Gruen1; Freya Mowat2; David Murdoch3; Natasha Olby1 1College of Veterinary Medicine, North Carolina State University; 2University of Wisconsin‐Madison; 3Duke University Medical Center Aging dogs suffer from Cognitive Dysfunction Syndrome (CDS), a condition in which cognitive decline is associated with amyloid pathology and cortical atrophy. Diagnosis is made through physical examination, elimination of systemic/metabolic conditions and completion of clinical metrology instruments (CMI) by owners. The purpose of this study was to evaluate the correlation between two frequently used CMIs, testing of different cognitive domains and plasma neurofilament light chain concentration (pNfL) in aging dogs. Senior and geriatric dogs were recruited. Owners completed the Canine Dementia Scale (CADES), and Canine Cognitive Dysfunction Rating scale (CCDR); dogs underwent physical and neurological examinations, routine blood work and urinalysis. Testing of executive control, working memory, social cues, and sustained attention was performed and pNfL was measured. Comparisons between CADES, CCDR scores, cognitive testing scores, and pNfL were made using logistic regression. Fourteen dogs from eight breeds were recruited (9.3 to 15.6 years). CADES scoring classified four dogs as severe CDS, two as moderate, two as mild and six as normal. CCDR identified four dogs at risk of CDS and ten as normal. A significant positive relationship was found between CADES score and pNfL (p = 0.015). CADES score was associated with poor performance on sustained attention (p = 0.004) and executive control (p = 0.0005). The CCDR scale did not correlate with cognitive testing or pNfL. Our findings suggest that a multi‐dimensional approach utilizing a combination of CADES, cognitive testing (sustained attention, executive control) and pNfL concentration can differentiate dogs affected with age‐related cognitive dysfunction from cognitively healthy aged dogs. ABSTRACT O01 Feline T‐cell low‐grade intestinal lymphoma: A novel model of lymphomagenesis according to the one‐health concept Valérie G. Freiche 1; Nathalie Cordonnier1; Maria Elena Turba2; Thierry Molina3; Olivier Hermine3; Julie Bruneau3; Lucile Couronné3 1Ecole Nationale Vétérinaire d'Alfort; 2Laboratorio Genefast; 3Hôpital Universitaire Necker Feline T‐cell low‐grade intestinal lymphoma (T‐LGIL) is an indolent disease, recognized as the first digestive neoplasm in cats. The condition is characterized by the infiltration of the gastrointestinal tract by neoplastic T‐lymphocytes. T‐LGIL shares common clinical, paraclinical and ultrasonographic features with lymphoplasmacytic enteritis (LPE). Establishing a final diagnosis is challenging. Moreover, the disease shares similarities with digestive indolent T‐cell lymphoproliferative disorder in human. As a result, translational research in feline T‐LGIL was considered relevant to improve understanding of the human condition, which is rare and still poorly defined. We prospectively analyzed clinical, paraclinical data and full‐thickness small intestinal biopsies from 22 domestic cats diagnosed with T‐LGIL and 22 cases diagnosed with LPE. A novel extensive histopathological and molecular study including T‐cell receptor clonality analysis was performed on all samples. Separate assessment of the epithelium and the lamina propria was achieved. Differentiation criteria between feline T‐LGIL and LPE included villous atrophy, lymphocytic cryptitis, depth of infiltration, apical‐to‐basal gradient of cellularity, nest and plaques identification and fibrosis extent within the lamina propria revealed by Trichrome de Masson's staining. CD3 and Ki67 expression levels in lamina propria and intra epithelial lymphocytes (IEL) were significantly increased in T‐LGIL cases as compared with LPE cases. All T‐LGIL were PhosphoStat3‐ and PhosphoStat5+ in contrast to LPE. Clonality assessment revealed monoclonal TCR rearrangement in 82% of the T‐LGIL cases and in 40% of the IBD cases. This prospective study specifically focuses on the pathogenesis and diagnosis of T‐LGIL: a new model of lymphomagenesis has emerged from this comparative research and suggests a continuum between inflammatory enteropathy towards digestive lymphoma. Finally, strong similarities between feline T‐LGIL and human indolent T‐cell gastrointestinal lymphoproliferative disorders are highlighted. ABSTRACT O02 External beam radiation therapy for the treatment of canine appendicular osteosarcoma: 77 cases Carissa J. Norquest 1; Brian Flesner1; Charles Maitz1; Jeffrey Bryan1; Melanie Moore2; Tara Ehling3; Jimmy Lattimer1 1University of Missouri—Veterinary Health Center; 2Care Center—Cincinnati; 3University of Missouri—Veterinary Health Center (Wentzville) Radiation therapy (RT) is used for local pain alleviation in dogs with appendicular osteosarcoma, especially among dogs that are poor surgical candidates for amputation. Recently published fracture rates for stereotactic body RT are >60%. However, historical fractionated protocols lack time to fracture and fracture rates. The objectives of this retrospective study were to determine fracture rate, tolerability, progression‐free interval and survival time of dogs receiving RT (coarse or fine fractionated) for appendicular osteosarcoma. Seventy‐seven dogs that received RT between 2006–2018 as part of treatment for appendicular osteosarcoma were available for evaluation. Seventy‐one received coarse fractionation while the remaining six received fine fractionation. The overall pathologic fracture rate was 31%. Pathologic fracture rate was significantly higher for dogs that received fine fractionation RT (83%) compared to dogs that received coarse fractionation RT (26%), p = 0.0096. The overall progression free interval (PFI) and overall survival time (OST) were 77 days and 109 days, respectively. Factors that increased both PFI and OST included improvement within 30 days of starting RT, completion of RT, and administration of chemotherapy. Increased serum ALP negatively affected both PFI and OST. Survival was significantly shorter in dogs that received coarse RT without bisphosphonates than those that received coarse RT with zoledronate (p = 0.020, log‐rank). In conclusion, coarse fractionated RT is recommended over fine fractionated RT due to lower risk of pathologic fracture and similar PFI. Prospective evaluation of combined coarse fractionation RT and zoledronate, especially for dogs with poor surgical candidacy, is warranted for the treatment of canine appendicular osteosarcoma. ABSTRACT O03 Evaluation of the association between interleukin‐6 and thrombopoietin concentrations with thrombocytosis in dogs with carcinoma Adrienne B. Cheney 1; Deborah Knapp2; George Moore2; Andrew Woolcock2 1College of Veterinary Medicine; Purdue University; 2Purdue University Carcinoma‐associated thrombocytosis is well documented in people, and pre‐treatment thrombocytosis has been shown to predict prognosis and response to therapy in certain epithelial tumors. In carcinoma‐associated thrombocytosis, the tumor has been shown to produce interleukin‐6 (IL‐6) and thrombopoietin (TPO) causing increased thrombopoiesis. Thrombocytosis has been evaluated in dogs, and neoplasia is a common diagnosis in 25–55% of these patients. Carcinoma is the most common tumor diagnosed in dogs with concurrent thrombocytosis and neoplasia, however the association between carcinoma and thrombocytosis in dogs has only been investigated retrospectively. The objective of this proof‐of‐concept study was to evaluate the concentrations of IL‐6 and TPO in dogs diagnosed with carcinoma with or without a thrombocytosis. We hypothesized that IL‐6 and TPO concentrations would be greater in dogs with carcinoma compared to controls, regardless of platelet count. We further hypothesized that IL‐6 and TPO concentrations would be greater in dogs with carcinoma and thrombocytosis when compared to dogs with carcinoma and normal platelet counts. Dogs with a histologic diagnosis of carcinoma were included in the study, and pre‐treatment EDTA blood was collected for complete blood count including platelet, and serum was collected for measurement of IL‐6 and TPO by enzyme linked immunosorbent assay (ELISA). A second group of healthy control dogs was recruited for comparison of blood platelet counts and serum concentrations of IL‐6 and TPO. Data were non‐parametrically distributed, and summary descriptive statistics presented as median [range]. Nonparametric numerical data for groups was assessed with the Wilcoxon rank sum test and Spearman rank correlation coefficient. One‐hundred and sixteen dogs were included in the study; 61 of these were diagnosed with carcinoma, and 55 dogs were healthy controls. The median platelet counts of the two groups were 349 × 103/mL [161–660] and 263.5 × 103/mL [146–459], respectively. Of the dogs with carcinoma, 12/61 (19.6%) had a thrombocytosis with the median platelet count in this sub‐group being 548.5 × 103/mL [533–660]. The median concentration of IL‐6 was not different between the carcinoma and control dogs (9.70 pg/ml [0–181.53] vs. 3.03 pg/ml [0–280.77], p = 0.155). Median TPO concentration was significantly higher in the dogs with carcinoma when compared to controls (87.42 pg/ml [0–>600] vs. 15.99 pg/ml [0–>600], p < 0.001). There was no difference in IL‐6 concentrations when the dogs with carcinoma were stratified by platelet count. Median TPO concentration was higher in the dogs with carcinoma and thrombocytosis when compared to those with normal platelet counts, but this difference did not reach significance (80.16 pg/ml [0–302.435] vs. 44.84 pg/ml [0–>600], p = 0.11). There was no significant association between TPO concentration and platelet count (r = −0.13, p = 0.32). These findings confirm that TPO concentrations are significantly increased in dogs with carcinoma, regardless of platelet count. While we did not establish TPO as a predictor of carcinoma‐associated thrombocytosis, this may be due to the low number of patients with a concurrent thrombocytosis in this study. TPO is likely to be one of multiple factors which can impact platelet number, production, and consumption in dogs with carcinoma. Future research is necessary to determine if TPO is a valuable biomarker in the diagnosis, staging, or treatment of canine carcinoma. ABSTRACT O04 Prognostic utility of computed tomography radiomic features for canine lung tumors: An analytical study Hannah Able; Amber Wolf‐Ringwall; Aaron Rendahl; Christopher Ober; Davis Seelig; Chris Wilke; Jessica Lawrence University of Minnesota Tumor heterogeneity is a well‐established marker of tumor behavior and it has been associated with prognosis in human lung tumors. Quantitative analysis of computed tomography (CT) radiomic features is an indirect measure of tumor heterogeneity. The purpose of this study was to extract CT radiomic features from canine primary pulmonary tumors and correlate features to histopathologic diagnosis or survival. First‐order statistical‐based CT texture features were extracted from segmented tumor volumes. Time to tumor progression (TTP) and survival were calculated as days (d) from the date of CT scan. Sixty‐nine tumors from 67 dogs were evaluated. Fifty‐seven tumors were classified as carcinomas and 12 as non‐carcinomas. Fifteen dogs had metastasis. All dogs were treated with surgical resection; 15 dogs received postoperative chemotherapy. Median tumor volume was 34 cm3 (0.1–1196 cm3). There was wide variation in first‐order statistics. Mean Hounsfield units (HU) ratio (p = 0.022) and median mean HU ratio (p = 0.021) were significantly higher in carcinomas than non‐carcinomas. Tumor sphericity was strongly correlated to volume (rs = 1.0) and mean HU was strongly correlated to median HU (rs = 0.9); other parameters were not correlated with each other. Median TTP and overall median survival time (MST) were 229 d and 322 d, respectively. MST was significantly longer (p = 0.0092) for carcinomas (357 d) compared to non‐carcinomas (56 d). When carcinomas were considered separately, volume was significantly associated with TTP (p < 0.0001) and MST (p < 0.0001). Metastasis at diagnosis significantly decreased MST (78 d versus 407 d; p = 0.008). Further study of radiomic features in canine lung tumors is warranted, particularly given that it non‐invasively provides additional tumor data. ABSTRACT O05 High Ki67 expression is associated with poor prognosis in canine B‐cell chronic lymphocytic leukemia Emily D. Rout 1; Julia Labadie2; Janna Yoshimoto1; Kaitlin Curran3; Anne Avery1 1Colorado State University; 2Fred Hutchinson Cancer Research Center; 3Oregon State University Human B‐cell chronic lymphocytic leukemia (BCLL) has a highly variable clinical course. Canine BCLL is generally considered an indolent disease, but previous studies demonstrate a wide range in survival times. Our objective was to evaluate clinical outcome in a larger population of BCLL patients and identify clinical or flow cytometric prognostic factors. A retrospective study was performed evaluating clinical presentation, flow cytometry features and overall survival in 121 BCLL patients. BCLL was defined as >5,000 lymphocytes/μL in the blood with an expansion of small‐sized CD21+ B cells (>60% of the lymphocytes) by flow cytometry. Three breed groups were represented: small breed dogs (n = 55) due to increased risk of BCLL; Boxers (n = 33) due to preferential use of unmutated immunoglobulin genes, which is associated with poor prognosis in human BCLL; other breeds (n = 33) to compare outcome to small breed cases. Proliferation, determined by the percent of Ki67‐expressing B cells by flow cytometry, was evaluated in 39/121 cases. The median overall survival time (MST) for all cases was 10.5 months (range, 1 day ‐ 55 months). Boxers had significantly shorter survival (MST, 5.9 months) than non‐Boxers (MST, 14.1 months; p = 0.0003), and there was no significant difference in survival between small breeds and other non‐Boxer breeds. Cases with high Ki67 (>40% Ki67‐expressing B cells) had significantly shorter survival (MST, 5.8 months) than low Ki67 cases (MST undetermined) among all cases evaluated (p = 0.023), and non‐Boxer cases (p = 0.028). In conclusion, BCLL demonstrated a variable clinical course and Boxer dogs and cases with high Ki67 had more aggressive disease. ABSTRACT O06 Clinical differences in aberrant feline T‐cell leukemia phenotypes Klaudia Z. Polak 1; Emily Rout1; Julia Labadie2; Paul Avery1; Anne Avery1 1Colorado State University; 2Fred Hutchinson Cancer Research Center The three major neoplastic phenotypes seen in cats with lymphocytosis include CD4+CD5+ T‐cell, CD4‐CD8‐CD5+ (double negative [DN]) T‐cell, and CD5‐low‐expressing T‐cell. CD4+CD5+ T‐cell leukemia is the most common and has a prolonged clinical course, while the two aberrant T‐cell phenotypes, DN T‐cell and CD5 low T‐cell, are rarer and have significantly shorter survival times. We previously described the poorer prognosis of the aberrant T‐cell leukemia phenotypes, but small numbers of cases were evaluated. All CD5 low cases were grouped together regardless of CD4 and CD8 expression. Our objective was to examine a larger cohort of cases with aberrant T‐cell phenotypes, particularly among CD5 low cases, and investigate clinically important differences within the DN, CD4+, or CD8+ CD5 low subtypes. We performed a retrospective study evaluating clinical data and survival information in 54 cats with a flow cytometry diagnosis of an aberrant T‐cell phenotype (CD4+ with low CD5 expression, CD8+ with low CD5 expression, DN with low CD5 expression, and DN with normal CD5 expression) in peripheral blood. The aberrant T‐cell phenotypes, DN CD5+, CD4+ CD5 low, CD8+ CD5 low, and DN CD5 low, had statistically significant (p < 0.0001) differences in median survival times (MST) (613 days [n = 18], 146 days [n = 13], 139 days [n = 5], and 24 days [n = 18], respectively). Although the DN CD5+ phenotype has the longest MST, survival was significantly shorter in cases with splenomegaly and/or splenic mass (223 days; p = 0.0081) compared to cats without splenic abnormalities (MST, 774 days). Presence of anemia was significantly different between phenotypes (p = 0.021), and was more common in the DN CD5 low cats (67%) compared to DN CD5+ cats (18%). Peripheral lymphadenopathy across all phenotypes was rare. Blood smear interpretation of DN CD5+ cases reveals predominantly small mature lymphocytes, whereas DN CD5 low lymphocytes were variable and ranged from small to large and immature in appearance. In conclusion, there were marked differences in overall survival between aberrant T‐cell leukemia phenotypes. Cats with DN CD5 low T‐cell leukemia have a very poor prognosis and tend to be anemic, whereas cats with DN CD5+ T‐cell leukemia have more indolent disease, and splenic abnormalities are associated with reduced survival. ABSTRACT O07 Characterization of monoclonal gammopathies in patients with normal total proteins Christina Jeffries; R. Adam Harris; Paul Avery; A. Russell Moore Colorado State University Unexplained hyperproteinemia or hyperglobulinemia have been considered indications to perform serum protein electrophoresis (SPE) to rule out a myeloma associated serum paraproteinemia (M‐protein). We sought to characterize M‐proteins in samples with normal total proteins (≤7.5 g/dl for canine) submitted to a veterinary diagnostic laboratory. The archives at Colorado State University's Clinical Pathology Laboratory were searched for samples from canine patients that had SPE performed in 2019. The final interpretation and clinical data was recorded and evaluated. Additionally, cases with a M‐protein that were confirmed by SPE and immunofixation (IF) performed between 2014 and 2019 and had a TP ≤ 7.5 g/dL were characterized for albumin and globulin concentration, albumin globulin ratio (A:G), age, M‐protein isotype and concentration. In 2019, 127 canine samples had SPE performed, of which 68 had IF. 56 samples had a diagnosed M‐protein. 31 cases of M‐protein were confirmed by IF. M‐protein containing samples were not more likely to have hyperproteinemia (p = 0.11, OR 1.79, 95% CI 0.97–3.7), hyperglobulinemia (p = 0.83, OR 0.89, 95%CI 0.30–2.7), or hypoalbuminemia (p = 0.37, OR 1.57, 95% CI 0.60–4.5). IF evaluation was available at M‐protein diagnosis for 11/13 (84.6%) samples with a normal total protein, and 7/8 (87.5%) samples with a normal globulin. To confirm that IF was an integral part of the initial diagnosis, 7 electrophoretograms with an IF confirmed M‐protein, normal total protein and normal globulin were reviewed by 2 pathologists blinded to the IF results; the M‐protein could not be identified in any of the cases, though a suspicious restricted band was noted in 5 samples. Due to lack of IF on all samples, the overall incidence of M‐proteins could not be determined. Twenty‐seven cases with TP ≤ 7.5 g/dl and a SPE and IF confirmed diagnosis of M‐protein were identified between 2014 and 2019. Records were available for 11/27 cases which indicated SPE and IF were performed due to concern for an underlying paraproteinemia secondary to multiple myeloma or secretory plasma cell tumor or B‐CLL. The mean age at diagnosis was 9.5 years (Min 3, Max 14). M‐protein was identified in samples with a total protein as low as 5.2 g/dl. The mean albumin concentration was slightly decreased at 2.7 g/dl (Min 1 g/dl, Max 3.6 g/dl). The mean globulin concentration was slightly elevated at 3.9 g/dl (Min 2.4 g/dl, Max 6.3 g/dl) yet was within normal limits in 10/27 cases. The mean A/G was slightly decreased at 0.7 (Min 0.2, Max 1.2). The M‐protein concentration mean was 1.3 g/dl (Min 0.4 g/dl, Max 3.6 g/dl) and could not be quantified in three cases. The incidence of M‐protein isotypes was 70.4% IgA (19/27), 14.8% IgM (4/27), 11.1% IgG (3/27), and 3.7% (1/27) light chain only. A normal total protein or normal globulin concentration in dogs does not rule out the possibility of an M‐protein, especially if there is a decreased A:G. IF may be helpful in these circumstances to identify low amplitude M‐proteins that may be missed with SPE alone. Additional studies are needed to determine if the A:G, age, and protein isotype distributions seen in this study are similar in dogs with the more typical M‐protein and hyperproteinemia. ABSTRACT O08 Exosomes derived from canine lymphoma cells induce M1 polarization of monocytes Akiyoshi Tani; Hirotaka Tomiyasu; Hajime Asada; Yuko Goto‐Koshino; Koichi Ohno; Hajime Tsujimoto The University of Tokyo Exosomes are small extracellular vesicles released from various types of cells. Exosomes play pivotal roles in intercellular communications and act as shuttles by transmitting signals and transferring their contents. In human medicine, it has been shown that exosomes derived from tumor cells exert immunomodulating effects on immune cells such as monocytes and lymphocytes in tumor microenvironment. Meanwhile, there have been few studies that examined these functions of exosomes in canine tumors. Therefore, the purpose of our study was set to investigate the immunomodulating effects of exosomes derived from a canine cell line (CLBL‐1) of diffuse large B cell lymphoma (DLBCL), which is one of the most common tumors in dogs, on monocytes. Canine monocytes were isolated from peripheral blood samples of healthy beagle dogs. The experimental animal care procedures were approved by the Animal Use and Care Committee of the University of Tokyo (P16‐172). At first, peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation, and CD14 positive monocytes were isolated from PBMCs using magnetic‐activated cell sorting (MACS) method. Exosomes were extracted from FBS‐free RPMI medium after culture of CLBL‐1 for 24 hours using commercially available exosome isolation reagent. Two‐hundred thousands of monocytes were incubated in RPMI medium containing 10% exosome‐depleted FBS with or without 80 μg/ml of CLBL‐1‐derived exosomes for 4 hours. After incubation, total RNAs were extracted from adherent monocytes, and the relative quantities of IL‐1β, IL‐6, IL‐10, TNFα and CD163 mRNAs were examined by RT‐qPCR. In addition, changes in gene expression profiles were comprehensively examined by RNA‐seq analysis using NextSeq 500. Read bases were aligned to the canine reference genome (CanFam 3.1), and differentially expressed genes (DEGs) were extracted as those with >1.5‐fold changes in expression levels and raw p‐value < 0.1. An online resource, DAVID v6.8, was used to identify biological functions and pathways associated with extracted DEGs, and a value of p < 0.05 was considered significant in this analysis. In RT‐qPCR analysis, it was shown that the expression levels of IL‐1β, IL‐6 and TNFα genes were significantly increased in exosome‐treated monocytes compared with control monocytes. On the other hand, there was no significant difference in expression levels of IL‐10 or CD163 gene. In RNA‐seq analysis, 214 genes were extracted as DEGs between exosome‐treated and control monocytes. Among these genes, 118 genes were upregulated and 96 genes were downregulated in exosome‐treated monocytes compared with control monocytes. Analysis using DAVID with these DEGs showed that these genes were significantly associated with intracellular signaling pathways including NF‐kappa β, TNF, and NOD‐like receptor signaling pathways. Results of RT‐qPCR indicated that treatment with exosomes derived from CLBL‐1 increased the expressions of cytokines associated with the phenotype of M1‐macrophage, which is classically considered to be pro‐inflammatory macrophages, in monocytes. RNA‐seq analysis revealed that extracted DEGs between exosome‐treated and control monocytes were significantly associated with NF‐kappa β signaling pathway, which was also reported to be activated in human monocytes or macrophages by treatments with exosomes derived from ovarian, breast and gastric cancers. It has been reported that the activation of NF‐kappa β signaling pathway leads to activate monocytes and inhibition of NF‐kappa β signaling in monocytes resulted in the reduction of tumor formation in a mouse model of human hepatocellular carcinoma. The results of this study indicated that exosomes derived from CLBL‐1 activated monocytes through intracellular signaling including NF‐kappa β pathway and increased the expressions of pro‐inflammatory cytokines associated with M1‐macrophage phenotype. The intercellular communications through exosomes might be potential targets of therapeutics for canine lymphoma, and further studies are warranted to investigate the roles of exosomes in pathophysiology of canine lymphoma. ABSTRACT O09 The VIGOR clinical trial: Anti‐tumor immunity induced by neoadjuvant oncolytic virotherapy in spontaneous osteosarcoma Kelly M. Makielski 1; Aish Sathyanarayan2; Michael Henson3; Kathleen Stuebner3; Alexandru‐Flaviu Tabaran3; Ingrid Cornax3; M. Gerard O'Sullivan3; Andrea Chehadeh3; Donna Groschen3; Kelly Bergsrud3; Lauren Mills3; Milcah Scott3; Aaron Sarver3; Michael Farrar3; Stephen Russell2; Shruthi Naik2; Jaime Modiano3 1Department of Veterinary Clinical Sciences, University of Minnesota; 2Mayo Clinic; 3University of Minnesota Oncolytic virotherapy is an emerging therapeutic modality resulting in tumor destruction through viral mediated tumor lysis and induction of antitumor immunity. Vesicular stomatitis virus (VSV) is an immunogenic oncolytic virus with tropism for osteosarcoma that is safe and showed preliminary signals of efficacy in dogs with spontaneous cancer. The aims of this placebo controlled clinical study were to evaluate neoadjuvant VSV therapy and characterize anti‐tumor immune responses in dogs with spontaneous appendicular osteosarcoma. Twenty‐eight dogs were randomized to neoadjuvant VSV or placebo arms, followed by amputation and carboplatin chemotherapy. Tumor tissue and peripheral blood mononuclear cells (PBMCs) were collected pre‐ and post‐treatment to characterize local and systemic antitumor immune responses. Osteosarcoma cell lines were established from each dog to characterize in vitro VSV susceptibility. VSV was well‐tolerated with mild, transient fever and acute, clinically inapparent cytokine responses. Tumor histopathology showed focal necrosis and inflammation in tumors from VSV‐treated dogs; RNA sequencing confirmed heterogeneity of immune cell infiltrates and cell cycle activation in the tumors. Massive parallel sequencing identified lymphocyte clones in tumors, lymph nodes, and PBMCs. Interim analyses suggest survival outcomes exceed those of historic control populations. Tumor pathology, in vitro correlates, and molecular immune responses are being correlated to survival outcomes. In conclusion, neoadjuvant VSV has an excellent safety profile, with preliminary evidence of clinical efficacy. These studies may shed light on the roles of viral oncolysis in initiating antitumor immunity and on biomarkers that are predictive of clinical efficacy in this heterogeneous canine cancer. ABSTRACT O10 Successful treatment of cutaneous neoplasias with electrochemotherapy in horses M. Carolina Duran 1; Valentina Soto1; Javier Ojeda2 1Universidad Austral de Chile; 2Universidad Austral Electrochemotherapy (ECT) with bleomycin was used to treat different cutaneous neoplasias in horses. ECT‐treatment sessions consisted in infiltration of tumoral masses with bleomycin (0.5 mg/cm3) using a 21 G needle followed by electroporation with electric pulses from an eight‐needle‐electrode. All treatments were performed under general anesthesia and repeated as needed every 3–4 weeks. A total of 6 sarcoid, 5 melanoma and 4 squamous cell carcinoma (SCC) masses were diagnosed and treated. Surgical excision of all sarcoids was performed followed by ECT‐treatment. The remained margins of 3 sarcoids were treated with 2 ECT‐treatment sessions while three with a total of 3 sessions. Surgical excision of melanomas (large perianal masses) and SCC (upper and lower eyelid masses) was not performed. Two smaller melanoma masses required 2 ECT‐treatment sessions, three bigger melanomas a total of 3 sessions. Two lower eyelid SCC masses were treated with 1 treatment session, two upper eyelid SCCs required 2 ECT‐treatment sessions. Response to treatment was considered as over 70% size reduction of the treated masses. Complete response in all 15 tumor masses treated with ECT with bleomycin was obtained, no reoccurrence was noted 4 months after the last treatment. Results show that ECT with bleomycin is an effective, safe, and simple local treatment of cutaneous neoplasias in horses. Nevertheless, general anesthesia is required for each treatment session and depending on the mass, several session and surgical excision is needed.   ABSTRACT O11 Inflammatory response and body composition of bitches with breast tumor supplemented with omega‐3 and glutamine Fabio Alves Teixeira 1; Brana Bonder1; Mariana Porsani1; Lucas Gonçales1; Julio Nagashima1; Clair de Oliveira1; Júlio César Balieiro1; Karina Pfrimer2; Gabriel Santos1; Denise Fantoni1; Marcio Brunetto1; Cristiana Pontieri3 1School of Veterinary Medicine and Animal Science, University of São Paulo; 2Ribeirao Preto Medical School, University of São Paulo; 3Nutritional Development Center, Grandfood Industry and Commerce LTD (Premier Pet) There is hypothesis that immunonutrients as omega‐3 fatty acids and glutamine can help treatment of oncologic patients due to their role in the immune and inflammatory response. This study aimed to verify inflammatory response and body composition of bitches with mammary tumor after mastectomy, during this three immunonutrients consumption. Under the approval of the Ethics Committee on Animal Use, twelve bitches with mammary neoplasia were divided into two groups: A—food without glutamine, EPA and DHA (91.4 g of protein; 57.1 g of fat and 5.0 g of fiber/1000 kcal); B—high protein food (60.4; 31.5 and 7.8) enriched with glutamine (3.5 g/1000 kcal) and fish oil (2.3 g of EPA + DHA/1000 kcal). They receive diets since 21 day before until 30 days after surgery. Serum measurements of TNF‐α, IL‐6, IL‐10, IGF‐1, C‐reactive protein (CRP) (Milliplex Map panel) and determination of body composition (deuterium method) were performed pre‐ and until post‐surgical moments. Statistical tests were used to compare the immunonutrients effects. There were no differences in the concentrations of different cytokines (p > 0.05) and CRP (p = 0.51) between groups. Group B had a higher concentration of IGF‐1 (p = 0.04), a higher percentage of muscle mass (p < 0.01) and less body fat (p < 0.01). The inclusion of glutamine and omega‐3, in the amounts evaluated in this study, were not sufficient to modulate the inflammation of bitches with breast tumors submitted to unilateral mastectomy, but they demonstrated a potential beneficial effect on the maintenance of body muscle mass. ABSTRACT O13 Targeted therapy pevonedistat promotes canine melanoma cell death through DNA replication and senescence (VCS award winner) Elizabeth A. Wood; Zhanping Lu; Shuai Jia; Anna Assumpção; Matthew Van; Mike Huelsmeyer; David Vail; Xuan Pan University of Wisconsin‐Madison MLN4924 (pevonedistat) is a potent and selective NEDD8‐activating enzyme (NAE) inhibitor. The NEDD8‐regulated neddylation system is responsible for the regulated degradation of intracellular proteins with important cellular functions in cancer cell growth, apoptosis, angiogenesis and metastasis. In human melanoma, inhibition of NAE results in induction of DNA re‐replication, S phase cell cycle arrest, DNA damage and apoptosis. The study aimed to assess the anti‐cancer effect of MLN4924 on canine malignant melanoma cell lines and patient samples and to elucidate the underlying mechanisms. Canine melanoma cell lines and primary patient samples were evaluated for cell viability after incubation with varying concentrations of MLN4924 or dimethyl sulfoxide. Apoptosis, cell proliferation and senescence assays were performed to address underlying mechanisms of MLN4924‐mediated anti‐tumor effects. Gene expression of seven previously identified deregulated genes in human melanoma was compared in sensitive vs resistant samples. MLN4924 treatment significantly reduced the viability of canine melanoma cell lines and primary samples in a dose‐ and time‐dependent manners. MLN4924 promoted cell apoptosis and inhibited cell growth through induction of DNA re‐replication and cell senescence. While the majority of canine melanoma samples demonstrated sensitivity at nanomolar ranges, some samples were resistant to the treatment. Modulation of P21 levels correlated with canine melanoma cell sensitivity. These results provided justification for further exploration of MLN4924 as a treatment of canine melanoma. ABSTRACT O14 Receptor tyrosine kinase dysregulation and biological activity of toceranib against canine urothelial carcinoma cell lines Daniela Korec 1; Darian Louke2; Joelle Fenger1 1College of Veterinary Medicine, The Ohio State University; 2The Ohio State University Transitional cell carcinoma (TCC) accounts for >90% of canine malignant tumors occurring in the urinary bladder. TCC tumors are generally inoperable and unresponsive to traditional chemotherapy, indicating a need for more effective therapies. Toceranib phosphate (Palladia) is a multi‐target receptor tyrosine kinase (RTK) inhibitor that exhibits potent activity against members of the split kinase family of RTKs, including vascular endothelial growth factor receptor, platelet‐derived growth factor receptor, Kit, and Flt‐3, resulting in both direct antitumor and antiangiogenic activity. Toceranib (TOC) demonstrated single agent activity against a variety of tumor types in a phase 1 study in dogs with cancer, including several carcinomas. In this clinical trial, 3 of 4 dogs with bladder TCC treated with TOC alone had stable disease for 10 weeks or greater. Preliminary retrospective studies suggested approximately 86.7% of dogs with TCC experienced clinical benefit (partial response or clinically meaningful disease stabilization) following toceranib (TOC) treatment; however, the basis for the observed responses to TOC is not known. The purpose of this study was to evaluate normal canine bladder tissues, primary bladder TCC tumors, and established TCC cell lines for the expression and activation of VEGFR1, VEGFR2, PDGFRα, PDGFRβ, and KIT to assess whether dysregulation of these RTKs may contribute to the biological activity of TOC. To provide an initial assessment of RTK expression, Real Time PCR was performed on primary TCC tissue samples (N = 10) and TCC cell lines (N = 5) to detect VEGFR2, PDGFRα, PDGFRβ, and KIT mRNA. Transcript for VEGFR2, PDGFRα, and PDGFRβ was detected in all TCC tissue samples and TCC cell lines; however, mRNA for KIT was not detectable in any samples. The Proteome Profiler™ Human Phospho‐RTK Array Kit (R & D Systems) provided a platform to assess phosphorylation of 42 different RTKs in primary TCC tissue specimens using the available flash frozen tumor specimens and TCC cell lines. In concordance with these data, PDGFRα, and PDGFRβ were found to be phosphorylated in all tumor samples and cell lines and KIT activation was not observed on the arrays. While message for VEGFR2 was identified in all tumor samples and cell lines, all samples exhibited low basal phosphorylation levels of this RTK. Core samples from all tumor samples and normal bladder tissues were available for evaluation and a tissue microarray was constructed to evaluate expression of receptors of interest and determine VEGFR, PDGFRα, and PDGFRβ immunoreactivity and localization in tumor cells and supporting stroma. Studies are ongoing to evaluate the in vitro activity of TOC on cell viability, apoptosis, and VEGFR, PDGFRα, and PDGFRβ phosphorylation in TCC cell lines. Taken together, our findings demonstrate that known targets of TOC are expressed/activated in primary TCC tumors and TCC cell lines. Given the observed phosphorylation of PDGFRα and PDGFRβ, these RTKs merit further investigation as to their role in mediating the biology of TCC and their contribution to TOC's activity. ABSTRACT O15 Plasma cytokeratin 18 and fecal alpha‐1 antitrypsin concentrations in dogs with osteosarcoma receiving carboplatin chemotherapy Kate Taikowski 1; Adam Rudinsky1; Darian Louke1; Emma Warry2; Joelle Fenger1 1College of Veterinary Medicine, The Ohio State University; 2College of Veterinary Medicine Texas A&M University Gastrointestinal (GI) toxicity is a frequently encountered adverse side effect in both humans and dogs receiving cytotoxic chemotherapy. Chemotherapy‐associated GI mucositis can manifest as pain, diarrhea, and weight loss and represents a major dose‐limiting side effect of chemotherapy that has a significant impact on patient quality of life. Cytokeratin 18 (CK18), one of the major components of intermediate filaments in simple epithelial cells, undergoes caspase‐mediated cleavage upon epithelial cell necrosis and apoptosis. Cellular apoptosis, a hallmark of GI mucositis, results in the release of CK18 into the circulation and data generated in humans suggest that circulating CK18 levels correlate with severity of GI mucosal cell injury induced by graft‐versus‐host disease and drug‐associated GI mucositis. More recently, enteric markers such as fecal alpha1‐antitrypsin (A1‐AT) that reflect increased intestinal permeability have been shown to correlate with the severity of lacteal dilation and GI protein loss in dogs. To date, no specific mechanistic biomarkers exist to aid in the screening/monitoring of pre‐clinical GI toxicity in dogs induced by cytotoxic chemotherapy. As such, the goal of this study was to evaluate the clinical utility of plasma CK18 and fecal A1‐AT levels as non‐invasive biomarkers of GI toxicity induced by cytotoxic chemotherapy. To address this, we conducted a prospective cohort study in client‐owned dogs (n = 10) diagnosed with appendicular osteosarcoma that previously underwent standard limb amputation. Dogs were treated with carboplatin chemotherapy (300 mg/m2 IV) on day 0. Plasma was collected on days 0, 7, and 21 and CK18 concentration was measured by ELISA (ABClonal). Feces was collected on days 0 and 21 and A1‐AT concentration was measured by ELISA (Creative Diagnostics). We hypothesized that plasma CK18 and fecal A1‐AT levels would increase following carboplatin administration due to drug‐induced GI epithelial cell damage/apoptosis, and that plasma CK18 and fecal A1‐AT levels would correlate with the severity of GI toxicity. Mean baseline plasma CK18 concentration was variable among patients; however, mean plasma CK18 concentration prior to carboplatin chemotherapy treatment was not significantly different from CK18 levels at day 7 or day 21 (day 0/baseline =11.66 ± 6.52 ng/ml, day 7 = 13.58 ± 8.33 ng/ml, day 21 = 12.03 ± 6.57 ng/ml, mean ± SD, p = 0.23). There was significant intra and inter‐patient variability in mean fecal A1‐AT levels at baseline. Mean fecal A1‐AT concentration did not change significantly from day 0 to day 21 (day 0 = 18.28 ± 7.38 ng/ml, day 21 = 15.03 ± 7.76 ng/ml, p = 0.20). In this study population, only 1 patient developed a grade 1 diarrhea, other gastrointestinal toxicity following chemotherapy was limited to grade 1 inappetence; therefore, we were unable to determine the association of plasma CK18 and fecal A1‐AT concentrations with the development of signs of GI toxicosis. In this study population, plasma CK18 and fecal A1‐AT concentration were not clinically useful biomarkers for the detection of GI toxicosis secondary to carboplatin administration. Further prospective evaluation of CK18 and A1‐AT as biomarkers of drug‐induced GI toxicity is warranted in a larger cohort of dogs receiving cytotoxic chemotherapy. ABSTRACT O16 A virome sequencing approach to feline oral squamous cell carcinoma to evaluate causative factors (VCS award winner) Shirley Chu 1; Jeffrey Bryan1; Obi Griffith2; Gayle Johnson1; Zachary Skidmore2; Kristine Wylie2; Todd Wylie2 1University of Missouri; 2Washington University Feline oral squamous cell carcinoma (FOSCC) may be the best naturally‐occurring model of human head and neck squamous cell carcinoma (HNSCC). HNSCC can be broadly divided into human papillomavirus (HPV)‐negative cancers and HPV‐positive cancers where HPV is the causative agent. Previous studies in FOSCC have used both species‐specific and species‐nonspecific PCR primers that may be insensitive to the detection of PVs and other viruses that may be divergent from known sequences. ViroCap is a targeted capture and next generation sequencing tool that was designed to identify all known vertebrate DNA and RNA viruses. In this study we used a metagenomic approach using ViroCap for DNA viruses in 20 FOSCC, 9 normal feline oral mucosal, and 8 suspected PV positive control samples. We tested the hypothesis that viruses would be enriched in FOSCC compared to normal oral mucosa. The virome of the FOSCC and normal feline oral mucosa consisted of feline foamy virus in 7/20 and 2/9 (35% and 22%), feline torque teno virus in 2/20 and 0/9 (10% and 0%), alphaherpesvirus in 2/10 and 0/9 (10% and 0%), FIV (0% and 22%), Epstein‐Barr virus in 1/20 and 0/9 (5% and 0%) and feline papillomavirus in 1/20 and 0/9 samples (5% and 0% respectively). Felis catus papillomavirus‐3 was found in 1 of 20 FOSCC samples. A virus was not associated consistently with FOSCC. If PVs have a role in FOSCC it is at most a supplementary or uncommon role. FOSCC appears most closely related to HPV‐negative HNSCC. Future research on FOSCC should focus on identifying genetic and environmental causes.   ABSTRACT O17 Concurrent treatment of multiple canine mast cell tumors with intratumoral tigilanol tiglate Pamela D. Jones; Graham Brown; Justine Campbell Qbiotics Aims: To determine the safety and efficacy of tigilanol tiglate for the concurrent treatment of up to 3 mast cell tumors (MCT). Methods: Eighteen dogs diagnosed with forty‐eight MCT were treated with tigilanol tiglate (1 mg/ml) by intratumoral injection. Patients received corticosteroids, H1 and H2 antagonists as part of treatment regime to minimize potential effects of degranulation reaction. On the day of treatment, the volume for each individual MCT was measured using the modified ellipsoidal method and the dose of tigilanol tiglate determined based on calculated volume of 0.5 mg per 1 cm3 of tumor (50% v/v). Dogs were excluded if total tigilanol tiglate dose exceeded 0.25 mg/kg bodyweight or was greater than 5 mg. Patients were clinically assessed at days 1, 7, 14 and 28, and all adverse events recorded using VCOG classification. Efficacy was assessed for each treated tumor at day 28 as wither complete response (CR) or not‐CR using RECIST criteria. Results: Forty‐five tumors (93%) had achieved a CR at day 28 following a single injection of tigilanol tiglate. Only 3 tumors on 3 separate dogs did not achieve CR. All adverse events were graded mild to moderate with no or minimal intervention required. Conclusions: This small pilot study suggests that tigilanol tiglate was well tolerated and efficacious for concurrent local treatment of multiple MCTs. Clinical significance of the results: Tigilanol tiglate can be used for concurrent treatment of multiple canine MCTs. ABSTRACT O18 Arterial thromboembolism of metastatic malignant neoplasm origin in two cats Fernanda Vieira Amorim da Costa; Gabriela Schaefer; Isabella da Silva; Tayná Veronezi; Bárbara Rivas; Paula Ribeiro; Cristiano Gomes; Saulo Pavarini Universidade Federal do Rio Grande do Sul In cats, arterial thromboembolism (ATE) is an acute and severe clinical condition often related to hypertrophic cardiomyopathy, but there are few reports of its association with neoplasms. The aim of this study is to describe two cases of ATE of neoplastic origin. The first case report is a 14‐year‐old crossbreed female cat presented with sudden pelvic limb paralysis during 24 hours. Clinical and laboratory alterations included absence of a bilateral femoral pulse, hypothermia, hypotension, bradycardia, neutrophilic leukocytosis, lymphopenia, hyperproteinemia, azotemia, metabolic acidosis, hyperlactatemia, increased serum activity of ALT and hyperkalemia. The electrocardiogram indicated sinoventricular rhythm, and echocardiogram evaluation showed no alterations. Thorax radiographic evaluation revealed small areas of radiopacity in the pulmonary fields. Doppler ultrasonography evidenced a cranial aortic thrombus at the bifurcation of iliac arteries. The patient was hospitalized for clinical stabilization, which included fluid therapy, tramadol, dipyrone, acepromazine, heparin and clopidogrel. Abdominal aorta arteriotomy for thrombus removal was performed 24 hours after patient's admission. Blood gas analyses, performed sequentially, showed persistent metabolic acidosis and hyperkalemia, despite treatment with sodium bicarbonate, regular insulin associated with glucose, and calcium gluconate. The cat died in the postoperative period. Necropsy examination was compatible with pulmonary adenocarcinoma with lymph node metastasis. The second case report is a 12‐year‐old crossbreed female cat with a history of mastectomy two days earlier due to mammary carcinoma. Previous thorax radiographic evaluation revealed a discrete opacification of lung fields, and echocardiogram showed no alterations. The cat was admitted presenting acute pain and paralysis of the pelvic limbs. Physical examination revealed hypothermia, cold and painful pelvic limbs and, cyanotic foot pads. Laboratory findings demonstrate neutrophilia, thrombocytopenia, azotemia, increased serum activity of ALT and creatine phosphokinase (CPK). Clinical stabilization included fluid therapy, methadone, ampicillin, heparin and clopidogrel. During hospitalization, serum ALT and CPK levels decreased, but azotemia worsened significantly (creatinine 15.7 mg/dL). In addition, the cat developed oliguria (urine output <0.4 ml/kg/h) which was compatible with severe acute kidney injury (AKI). The patient presented hypotension and died few hours later. Necropsy showed several areas of nodular metastases in the lungs, compatible with metastatic mammary carcinoma by histopathological examination. There was a fibrin thrombus obstructing the aortic trifurcation and a firm whitish mass dorsal to that, which on microscopic examination showed neoplastic proliferation identical to those found in the lungs. Pelvic limb muscles showed areas of muscle necrosis. Infarction was observed on the left kidney, as well as several thrombosis areas. Both cats in the present study had major complications that were difficult to manage, such as ischemia and reperfusion syndrome associated with persistent hyperkalemia and AKI, culminating in death. The prognosis of this condition may be poor and neoplastic thromboembolism should be included as a differential diagnosis of cardiogenic thromboembolism. ABSTRACT O19 Anticancer drug treatment increases cancer stem like cells in canine lymphoma cells Tomoko Okusa; Kenji Baba; Masaya Igase; Satoshi Kambayashi; Takuya Mizuno; Masaru Okuda Yamaguchi University Canine lymphoma is a type of malignant hematological tumors that develops frequently. The multidrug combination therapy used for the treatment is known to have a good outcome with great sensitivity. However, even in those good outcome cases, recurrent lymphoma occurs, resulting in their deaths. This is caused by the anticancer drug resistance. In human, a sub‐population of lymphoma cells showing the cancer stem cell (CSC) like characteristics has been reported to increase by exposure to anticancer drugs. The purpose of this study is to clarify the relationship between the CSC characteristics and the anticancer drug resistance in canine lymphoma cells. In this study, the drug resistant cells were prepared using the canine lymphoma cell lines by continuous exposure to ACNU, doxorubicin or L‐asparaginase, or by exposure to a HDAC inhibitor, phenyl butyrate (PB), for 48 hours. A colony formation ability in the soft agar, that was one of the CSC like characteristics, was high in the resistant cells, and it is thought that this CSC like characteristics participates in the resistant acquisition of the cancer cells. In particular, in the group exposed to PB, the colony formation ability was nearly twice higher than those in the unexposed group. It is necessary to identify a factor related with the drug resistance and the CSC like characteristics in the near future. ABSTRACT EN01 Treatment failure in hyperthyroid cats following radioactive iodine (I‐131) injection Deirdre Mullowney; Yu‐Mei Chang; Barbara Glanemann; Harriet Syme Royal Veterinary College Radioactive iodine (RAI) is considered the optimal treatment for hyperthyroidism in cats. For convenience, blood sampling is commonly performed immediately before hospital discharge, when total thyroxine (T4) may not have reached its nadir. The purposes of this study were to determine the frequency of, and predictors for, eventual resolution of hyperthyroidism in cats for which T4 remains high at discharge, and to report clinical outcomes for cats that failed initial RAI treatment. Medical records for 959 cats treated with RAI were reviewed. At discharge (15 or 23 days post‐injection), 89 cats had T4 > 40 nmol/l. Of these, 35 (39%) subsequently had T4 < 40 nmol/l (classified as treatment success). Binary logistic regression assessed the utility of T4 (pre‐, post‐ and percentage change), as well as day of sampling and dose of I‐131, as predictors of successful treatment. Only the T4 variables were predictive of successful treatment with post‐treatment T4 (p < 0.001) remaining in the final model. Cats with T4 between 40–100 nmol/l at discharge had a 67.5% chance of treatment success, compared with only 8.2% of cats with higher T4. Of the 54 cats that failed the initial treatment, 16 received a second dose of RAI, 12 underwent thyroidectomy and 21 restarted medical management (some cats received more than one treatment). Re‐treatment with RAI was successful in 13 (81%). Four cats had histopathologically confirmed thyroid carcinoma. Cats with T4 > 100 nmol/l at discharge have a low probability of becoming euthyroid and may be candidates for immediate re‐treatment. Success rates following re‐treatment with RAI are good. ABSTRACT EN29 Day‐to‐day variability of porcine lente, insulin glargine u300 and insulin degludec in diabetic dogs Michelle J. Miller 1; Jully Pires1; Katti Crakes1; Rachel Greathouse1; Nina Quach1; Chen Gilor2 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis; 2Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida The human‐recombinant insulin formulations glargine (Toujeo®) and degludec (Tresiba®) are associated with less day‐to‐day variability and fewer hypoglycemic events compared to Lente‐type insulin in diabetic people but are largely unstudied in dogs. A repeated‐measured study was used to compare the pharmacodynamics of porcine Lente (Vetsulin®), Toujeo® and Tresiba® in seven diabetic dogs. A continuous glucose monitor (CGM) was placed on dogs throughout the study, recording interstitial glucose concentrations (IG) every 15 minutes. Each dog received the three insulin formulations consecutively. For each insulin, dose escalation was performed using the same algorithm until maximum dose was achieved. Maximum dose was then maintained for 5 days and the CGM data from this period were used for comparison between formulations. To assess day‐to‐day variability, the mean, SD and coefficient of variation (CV) were calculated at each of the 96 time points for each insulin for each dog and then the mean of these CV's for each dog was compared between insulin formulations. The maximum q12h dose was 0.7 U/kg, 0.5 U/kg and 0.4 U/kg, for Vetsulin®, Toujeo® and Tresiba® respectively. Vetsulin® was associated with increased day‐to‐day variability compared to Toujeo® and Tresiba® (mean CV 48% vs. 31% and 26% respectively, p = 0.002) but with lower mean IG and no difference in IG time spent <70 mg/dL (17%, 11%, 9% respectively, p = 0.2). Toujeo® and Tresiba® can maintain lower day‐to‐day variability in dogs but overall glycemic control might not be better than with Vetsulin®. ABSTRACT EN03 Iatrogenic effect of trilostane (vetoryl) on adrenal steroids synthesis in dogs Luca Giori 1; Alejandro Esteller‐Vico2 ; Jillene Sennon‐Greene2 ; Hugo Eiler2; Kellie Fecteau2 1College of Veterinary Medicine, University of Tennessee; 2BDS Department, College of Veterinary Medicine, University of Tennessee Trilostane is one of the treatment options for hyperadrenocorticism (HAC). In dogs, clinical signs of HAC often poorly correlate with serum cortisol concentration. We hypothesized that treatment of canine HAC with trilostane results in increased serum concentration of adrenal sex steroids, which can contribute to clinical signs of HAC in dogs. We performed a retrospective analysis of 529 canine blood serum samples submitted to our institution's Endocrinology Laboratory (2015–2019). Serum samples from gonadectomized males and females were evaluated for cortisol, androstenedione, estradiol, progesterone, 17beta‐hydroxyprogesterone (17OHP), testosterone and aldosterone at pre‐ and post‐ACTH stimulation. Samples were divided into 3 groups: 0) dogs with HAC, and no reported treatment (n = 109); 1) dogs with HAC and receiving trilostane (n = 319); and 2) dogs with HAC, with discontinued therapy after poor response (n = 101). Group 1 had significantly lower cortisol concentrations pre‐ and post‐ACTH stimulation (mean ± SEM = 4.0 ± 0.2 and 8.3 ± 0.4 μg/dL, respectively) compared to dogs in Group 0 (6.6 ± 0.5 and 21.5 ± 0.9 μg/dL) and Group 2 (5.5 ± 0.3 and 16.3 ± 1.0 μg/dL). Group 1 had significantly higher androstenedione and 17OHP concentrations pre‐ and post‐ACTH stimulation, compared with Groups 0 and 2. No significant differences in steroid concentrations were detected in dogs treated once versus twice a day. Even though cortisol was lower and within the reference interval in Group 1, dogs were reported to have polyuria‐polydipsia (39.8%), alopecia (15.9%), and polyphagia (10.3%), among other clinical signs of HAC. ABSTRACT EN04 Evaluation of a flash glucose monitoring system in dogs with rapidly changing glucose concentrations Carly Patterson; Leigh Howard; Jonathan Lidbury; Shannon Washburn Texas A&M University A flash glucose monitoring system (FGMS; FreeStyle Libre 14‐day system, Abbott Laboratories) has been evaluated in dogs with uncomplicated diabetes mellitus, as well as dogs with diabetic ketoacidosis. It continuously measures interstitial glucose concentrations for up to 14 days and has proven to be a useful tool for monitoring diabetic dogs that predominantly have hyperglycemia. The utility of this system for detecting hypoglycemia and rapid changes in glucose concentrations has not yet been evaluated in dogs. The objective of this study was to assess the utility of this FGMS in dogs with hypoglycemia and rapid changes in blood glucose concentrations. This IACUC approved study was performed in tandem with a teaching laboratory during which veterinary students administered intravenous regular insulin to 24 fasted dogs and corrected the resulting hypoglycemia by feeding or administering dextrose intravenously; a single subcutaneous dose of dexamethasone was also administered. FGMS sensors were placed 1 hour prior to administration of insulin. A FGMS measurement and a blood sample (collected from a peripheral intravenous catheter) were obtained prior to insulin administration and every 10 minutes over a two‐hour period. Blood glucose measurements were promptly made on each sample using a clinical chemistry analyzer (Vitros 4600, Orthos Diagnostics). Glucose concentrations were compared between the two methods for each time point with the clinical chemistry analyzer serving as the reference standard. Agreement between methods was assessed using linear regression and Bland‐Altman analysis. The application of the FGMS was uncomplicated and well tolerated by all dogs. However, out of 240 possible readings, 17 sensor errors (7.1%) were reported by the FGMS. When comparing the FGMS and reference standard glucose concentrations, R2 was 0.21, p > 0.001 and bias (reference standard minus FGMS; 95% CI) was −12.1 mg/dL (39.3 to −63.6 mg/dL). Out of 93 measurements where the reference standard concentration was <60.0 mg/dL, the FGMS measurement was >60 mg/dL for 64 (69%), was >80.0 mg/dL for 18 (19%), and was >100.0 mg/dL for 3 (3%). In this experimental model of dogs with hypoglycemia and rapid changes in blood glucose concentrations, there was limited agreement between FGMS and reference standard glucose measurements and the FGMS failed to reliably detect hypoglycemia. In general, the FGMS measurements were higher than those for the reference standard but this was not consistent, making use of an adjustment factor impossible. These results likely reflect the time it takes for interstitial glucose concentrations to equilibrate with those in the bloodstream. ABSTRACT EN05 Evaluation for type 1 diabetes associated autoantibodies in diabetic and non‐diabetic Australian Terriers and Samoyeds Allison L. O'Kell 1; Mark Atkinson2; Paula Henthorn3; Rebecka Hess3; Clive Wasserfall2 1College of Veterinary Medicine, University of Florida; 2University of Florida; 3University of Pennsylvania Evidence for an autoimmune etiology in canine diabetes is inconsistent, and could vary based on breed. The objective of this study was to evaluate for the presence of glutamic acid decarboxylase 65 (GAD65), insulinoma‐associated protein 2 (IA‐2), and zinc transporter 8 (ZnT8) autoantibodies in diabetic and non‐diabetic Australian Terriers and Samoyeds, two breeds with comparatively high prevalence of diabetes, in the United States. Banked serum samples from Australian Terriers (n = 63 diabetic; n = 71 non‐diabetic) and Samoyeds (n = 32 diabetic; n = 42 non‐diabetic) previously recruited from United States primary care clinics, breed club events, or academic hospital patient populations were included. Autoantibodies against GAD65, IA‐2, and ZnT8 were measured using commercially available kits with specificity for the human proteins. Samples were considered positive if results were above the lower limit of quantification. A Fisher's exact test compared the proportion of dogs in the diabetic and non‐diabetic groups within each breed that were positive for each autoantibody. There was no significant difference in the proportion of samples considered positive for GAD65 or ZnT8 autoantibodies in either breed or IA‐2 autoantibodies in Australian Terriers (p > 0.05). The proportion of IA‐2 autoantibody positive samples was significantly higher in diabetic versus non‐diabetic Samoyeds (p = 0.003), but substantial overlap was present between diabetic and non‐diabetic groups. The present study did not support these autoantibodies as markers of autoimmunity in canine diabetes in the breeds studied here. Future studies investigating alternative markers of autoimmunity in these and other breeds are warranted. ABSTRACT EN06 The efficacy, sensitivity, and specificity of a saliva glucose monitoring system for diabetic canines Rebecca Silveston‐Keith 1 ; Delphine Dean2; Katherine Hafner3; Jeffery Ranta4 1Accessible Diagnostics; 2Clemson University; 3Medical Murray; 4Coastal Carolina University Monitoring blood glucose is critical for regulating canine diabetes mellitus (DM) glucose. Insulin regimens prescribed based on in‐office glucose curves do not necessarily reflect patients' glucose trends at home as canine blood glucose (BG) varies throughout the day and in response to different environmental stressors including office induced hyperglycemia. The American Animal Hospital Association (AAHA) 2018 Diabetes Management Guidelines for Dogs and Cats recommends incorporating at home BG results and clinical signs with in‐practice diagnostic exams for effective management of DM. At home systems such as portable blood glucose meters (PBGMs), continuous glucose monitors (CGMs) and urinary strips are not always used due to owner anxiety in lancing for blood, high cost, or lack of accuracy respectively. Furthermore, owners risk mis dosing insulin, based on this at home data, without veterinarian advice. Decades of research show that partnerships between health professionals and caretakers improve patients' healthcare outcomes. Integration of at‐home glucose monitoring into the standard of care provided in the veterinary practice improves the health of the patient if the at home test is effective and a professional can interpret monitoring modalities and blood glucose results in conjunction with clinical signs. The objective of this study was to validate the sensitivity, specificity and effectiveness of a painless, saliva glucose, smart phone enabled at home index test compared to venous blood test for diabetic canines. The side by side testing included 47 DM, and 9 clinically normal, privately owned, canines with informed owner consent under standard fee for service patient clinical care provided by participating veterinary practices. Patient saliva was sampled in duplicate non‐invasively and simultaneously with venous blood at two times 60 minutes apart. Automated lab scale blood chemistry analyzers determined the blood glucose. The smart phone proprietary app algorithm, Vet‐Tab, determined the corresponding blood glucose from the color change of glucose oxidase reaction with salivary glucose. Pet owners were surveyed about their use behavior for this saliva system, CGMs, PBGM and urine strips. They were also surveyed about their veterinarian relationships in response to the app prompting users to contact their vets for advice when the pet is outside a euglycemic range. The Vet‐Tab's salivary system had a positive predictive value for hyperglycemic to hypoglycemic canine venous blood glucose and has a system sensitivity and selectivity is comparable to that of accepted CGMs for diabetic companion animals when the collection and analysis of salivary glucose and BG was done by skilled professionals in a veterinary practice. The Surveillance Error Grid showed that 90% of measurements have only slight risk or no risk for complications due to inaccurate glucose readings in diabetic canines. Owners using Vet‐Tab report increased measurement compliance and confidence over other glucose monitoring systems and higher connectivity with their veterinarian. Vet‐Tab was shown to be an effective early warning system to supplement in‐practice assessments and increase the owner‐veterinarians partnership for improved healthcare of the DM patient.   ABSTRACT EN07 Organoid cultures of follicular‐cell thyroid carcinoma: A novel canine model for translational thyroid cancer research (ESVE award winner) Eve Tièche 1; Kerstin Hahn2; Martina Dettwiler2; Federico Massari3; Sandra Schallberger4; Martin Kessler5; Sven Rottenberg1; Miguel Campos1 1Department of Clinical Veterinary Science, Vetsuisse Faculty, University of Bern; 2Institute of Animal Pathology, Vetsuisse Faculty, University of Bern; 3DOCVET; 4Tierklinik Thun; 5Tierklinik Hofheim Growing patient‐derived tissue in 3‐dimensional cell culture systems (organoids) has revolutionized in vitro cancer research. In contrast to 2‐D cell lines, organoids can be grown more efficiently and conserve important features of the original tumor, such as tissue architecture and cellular heterogeneity. In human medicine, organoid cultures provide a unique platform for personalized cancer therapy. In this study, we aimed to culture and characterize organoids derived from follicular‐cell thyroid carcinoma (FTC) in dogs. Tissue samples of follicular type (n = 1) and compact type (n = 1) FTCs derived from two euthyroid dogs were frozen in DMSO‐containing freezing medium within 24 h of thyroidectomy and stored at −150°C until processing. After thawing, the tissue was digested with collagenase IV and dissociated mechanically. Cells were subsequently seeded in Cultrex® Basement Membrane Extract and cultured to organoids in Advanced DMEM supplemented with N‐acetylcysteine, B‐27 supplement, EGF, Noggin, Rspondin‐1 and Rock‐inhibitor. Organoids were split and passaged every 9 to 14 days. After 15 to 24 days, organoids were formalin‐fixed, pelleted in 2.5% agarose, paraffin‐embedded and processed for hematoxylin‐eosin staining. Immunohistochemistry (IHC) for thyroid transcription factor‐1 (TTF‐1), thyroglobulin (Tg), calcitonin, vimentin and Ki‐67 was performed on sections of the primary tumors and organoids. Organoids of FTC were cultured efficiently using our protocol. Organoids of both tumors formed follicle‐like structures composed of a single epithelial cell layer. These epithelial cells were round to cuboidal, had variably distinct cell borders and abundant eosinophilic to foamy cytoplasm. Anisocytosis and anisokaryosis were not observed in either of the organoid lines but were present in the FTC of compact type. Nuclear expression of TTF‐1 in both organoid lines confirmed thyroid origin. The organoids derived from the compact FTC, which had approximately 30% of cells positive to Tg, showed no Tg expression while the organoids derived from the follicular FTC, which had Tg expression in >95% of cells, showed Tg expression in about 50% of the organoids. Vimentin expression was observed in both organoid lines (30–60% of cells) and was higher than in the primary tumors, where only up to 10% of tumor cells were positive. IHC for calcitonin and Ki‐67 was negative in both organoid lines. Organoids derived from naturally occurring canine FTC are able to conserve histological and immunohistochemical features of the primary tumors providing an interesting in vitro model to better understand the pathogenesis and optimize treatment of thyroid cancer in dogs. The culture protocol likely requires further optimization. ABSTRACT EN08 Measurement of pre‐trilostane salivary cortisol in dogs with ACTH‐dependent hyperadrenocorticism Vanessa Uemura Fonseca 1,2; Gabriel Müller3; Cíntia Silva2; Vinícius Villas Bôas3; Paula Papa2,4 1School of Veterinary Medicine, University of Santo Amaro; 2School of Veterinary Medicine and Animal Science, University of Sao Paulo; 3Private Practice; 4Vetsuisse Faculty, University of Zurich Trilostane therapy is used for the management of spontaneous hyperadrenocorticism (HAC) in dogs. The monitoring is often performed by a combination of history, physical examination and assessment of adrenal reserve capacity with an ACTH‐stimulation test. Due to the cost and availability of synthetic ACTH for the test, other evaluation methods have been tested, such as urine corticoid:creatinine ratio and baseline cortisol values before and after trilostane administration. The measurement of one or two baseline cortisol pre trilostane has been shown to be promising. However, baseline cortisol can be influenced by stress during blood collection in a veterinary hospital. The cortisol passively diffuses from blood into the saliva, and if the saliva collection takes less than four minutes, there will be a minimal stress effect on the measurement. The goals of this study were: 1‐ to evaluate the accuracy of pre trilostane salivary cortisol measurements for classifying well and unwell‐controlled dogs, and 2‐ if there is a correlation between serum and salivary cortisol concentrations. Twenty‐six client‐owned dogs diagnosed with spontaneous ACTH‐dependent HAC and on BID trilostane treatment were prospective enrolled. The study was approved by the University of Santo Amaro Animal Care and Use Committee. Three measurements of cortisol were performed, two in the saliva and one in the serum. The first measurement of salivary cortisol was obtained with salivettes at home immediately before the administration of trilostane. And the second was obtained in a veterinary environment immediately after the end of the ACTH‐stimulation test, three hours after trilostane. The dogs were classified as well and unwell‐controlled, when post‐ACTH serum cortisol was between 1.5–5.5 μg/dl and greater or equal than 5.5 μg/dl, respectively. There were 9 well and 17 unwell‐controlled dogs. None of the animals had post‐ACTH cortisol value below 1.5 μg/dl. The accuracy of salivary cortisol in differentiating well and unwell‐controlled dogs determined by the area under the Receiver Operating Characteristic (ROC) curve was 0.79 with p = 0.032. The cut‐off value less than 0.089 μg/dl for detection of well‐controlled showed 71.4% of sensitivity and 86.7% of specificity, whereas a cut‐off less than 0.126 μg/dl had 85.7% of sensitivity and 66.7% of specificity. There were differences between salivary cortisol values post‐ACTH in well and unwell‐controlled group (p = 0.026), but no significant difference was observed between salivary cortisol pre‐trilostane in well and unwell‐controlled group (p = 0.087). The Spearman's rank‐order correlation showed that salivary cortisol post‐ACTH was moderately correlated with serum cortisol post‐ACTH (Rho = 0.536, p = 0.022). No correlation was observed between salivary cortisol pre‐trilostane and serum cortisol post‐ACTH (Rho = 0.342, p = 0.110), and between salivary cortisol pre‐trilostane and salivary cortisol post‐ACTH (Rho = 0.039, p = 0.889). These findings suggest that the salivary cortisol measurement may be a potential tool for monitoring HAC. Further research on a larger number of dogs is needed to balance the groups for statistical analyses and confirm the accuracy of this method. ABSTRACT EN09 Insulin expression patterns in canine insulinoma Thomas Schermerhorn; Tera Brandt; Sarah Schneider; Nora Springer Kansas State University Canine insulinoma is an insulin‐secreting endocrine tumor of pancreatic islet beta cells that causing hyperinsulinemia and hypoglycemia. Little is known about the insulin expression patterns in canine insulinoma or how expression influences hyperinsulinemia. This study used immunohistochemistry (IHC) to compare insulin expression patterns between normal islets and neoplastic tissue in sixteen insulinomas from an archived tissue bank. IHC slides were prepared by the Veterinary Diagnostic Histology Lab and insulin expression quantified using HALO image analysis software. Visual examination showed insulin in insulinoma cells was not concentrated within discreet granules. The mean percentage (%) of insulin staining area (+) within equally‐sized regions drawn around normal pancreatic islets (26.8%) and insulinoma tumor tissue (26.0%) was similar. Insulin staining was less intense in insulinomas (23.5% tumor area showed weak staining compared to 14.7% islet area) while 12% of islet area showed moderate or strong staining compared with 2.4% of tumor area. The ratio of insulin expression in tumor and islet (T:I ratio) showed that insulin expression varied between individual tumors (T:I ratio range—0.13 to 3.5); 4 tumors had T:I >1.5 (high insulin content) and 4 had T:I<0.2 (low insulin content). The pattern and intensity of insulin staining is variable in canine insulinoma suggesting insulin content differs between individual tumors. The majority of tumors contained abundant (‘high’) insulin suggesting over expression could underlie abnormal insulin secretion. Hyperinsulinemia and hypoglycemia associated with tumors with low insulin content suggests another mechanism, such as abnormal glucose sensing, could underlie abnormal insulin secretion. ABSTRACT EN010 Evaluation of salivary vasopressin as an acute stress biomarker in dogs with noise stress Jeong‐Mi Kim 1; Yi‐Kyeong Jeong2; Ye‐in Oh2; Kun‐ho Song2; Kyoung won Seo2 1College of Veterinary Medicine, Chungnam National University; 2Chungnam National University Stress is associated with various detrimental changes in physiological health, which affect an animal's quality of life. The hypothalamus‐pituitary‐adrenal (HPA) axis and the sympathetic‐adreno‐medullar (SAM) axis are two main physiological pathways that contribute to the stress response of an organism. Arginine vasopressin (AVP) is a mediator of the HPA axis and is known to be related to social behaviors and stress. The serum concentration of AVP is higher in more aggressive dogs and humans with post‐traumatic stress disorder. Salivary analysis is a non‐invasive method to assess stress. The purpose of this study was to evaluate the possibility of using salivary AVP as an acute stress biomarker in dogs. Salivary AVP concentration was measured before and after 30 minutes of vacuum noise exposure. Behavioral assessment, physiologic parameter change assessments, and serum cortisol analysis were conducted in combination. Statistical analysis was conducted twice in the total study population and in more stressed individuals. Based on stress behavior analysis scores, a total of 28 dogs were classified into mildly, moderately, and severely stressed groups. All four physiologic parameters (blood pressure, body temperature, heart rate, and respiratory rate) were significantly increased after noise stimulation in the severely stressed group. Serum cortisol did not show any significant change. Salivary AVP decreased after noise stimulation in the total population. Salivary AVP and blood pressure changes were negatively correlated in the severely stressed group. In conclusion, salivary AVP may be a potential acute stress biomarker in dogs. Table 1. Characteristics of dog participants Breed Number of dogs Sex of dogs (F/FS/M/MC) Maltese 8 1/6/0/1 Mongrel 6 0/4/0/2 Shih tzu 2 0/2/0/0 Poodle 2 0/0/0/2 Pomeranian 2 0/1/0/1 Yorkshire terrier 1 0/1/0/0 French bulldog 1 0/1/0/0 Beagle 1 0/1/0/0 Dachshund 1 0/0/0/1 Spitz 1 0/1/0/0 Cocker spaniel 1 0/0/0/1 Border collie 1 0/0/0/1   ABSTRACT EN11 Chronic low‐dose rapamycin does not affect glucose and insulin regulation in middle‐aged, large breed dogs Jeremy B. Evans 1; Stephanie Word1; Audrey Cook1; Matt Kaeberlein2; Daniel Promislow2; Kate Creevy1 1Veterinary Teaching Hospital, Texas A&M; 2University of Washington Rapamycin is an anti‐fungal macrolide that inhibits the mammalian target of rapamycin (mTOR) and is used frequently as an immunosuppressant in human renal transplant recipients. Strikingly, rapamycin administration has been shown to significantly extend the lifespans of numerous laboratory animal models when compared to placebo‐treated controls. Due to mTOR's extensive role throughout the body, rapamycin can cause numerous side effects, including derangements in glucose and insulin homeostasis. This study aimed to investigate any potential abnormalities in insulin sensitivity in middle‐aged, large breed dogs who received long‐term, low‐dose oral rapamycin. Seventeen dogs (10 spayed females, 1 intact female, and 6 castrated males) were randomly assigned to receive rapamycin (0.025 mg/kg) or a placebo orally every Monday, Wednesday, and Friday for 6 months. All enrolled dogs underwent complete evaluations (physical exam, chemistry, CBC, urinalysis, and echocardiogram) at baseline, 3 months, 6 months, and 12 months (i.e., 6 months after discontinuation of treatment), and excess blood samples were flash frozen in liquid nitrogen and then stored at −80°C. Samples from baseline and 6 months were analyzed to determine fasting insulin and glucose concentrations and a homeostatic model assessment for insulin resistance (HOMA‐IR) was calculated. Mean baseline HOMA‐IR scores were not significantly different between control and rapamycin treated groups (2.35 ± 2.1 and 2.14 ± 1.4, respectively; p = 0.82), nor at 6 months (2.61 ± 3.1 and 1.99 ± 1.3; p = 0.59). Additionally, the mean change in HOMA‐IR over 6 months was not significantly different between rapamycin and control groups (+0.26 ± 2.4 and −0.15 ± 1.5; p = 0.67). In this small study of low‐dose rapamycin in companion dogs, no overt impact on HOMA‐IR scores was detected. Future larger studies are warranted.   ABSTRACT GI01 Incidence of bacteremia secondary to colonoscopy in dogs Martin Granick 1; Faye Hartmann1; Jean‐Sébastien Palerme2; Jessica Pritchard1 1University of Wisconsin; 2Iowa State University In human medicine bacteremia is a common colonoscopy sequela with a reported incidence of up to 25%. While the majority of these bacteremias are asymptomatic, prophylactic antibiotic guidelines have been created to decrease sepsis risk in certain patient populations. The incidence of transient or clinical bacteremia secondary to colonoscopy has not been characterized in veterinary medicine. We hypothesized that similar to humans, a subset of dogs undergoing colonoscopy would develop bacteremia. Dogs with clinician prescribed colonoscopy were eligible for enrollment. Exclusion criteria included evidence of bowel perforation or concurrent antibiotic administration other than metronidazole. Blood cultures were obtained aseptically from either a cephalic or saphenous vein after anesthetic induction and immediately following colonoscopy. A total of 20 dogs were enrolled between January 2019 and January 2020. Positive blood cultures were detected in 4/20 dogs (20%) pre‐endoscopy and 4/20 dogs (20%) post‐endoscopy. Blood cultures were positive for one dog both pre‐ and post‐endoscopy although two different microorganisms were cultured. No dogs showed clinical signs consistent with sepsis. There was no difference in the incidence of positive blood cultures pre‐ and post‐colonoscopy. These preliminary results are consistent with other studies documenting bacteremia in 14–52% of clinically well dogs. Additional case recruitment as well as utilizing more sensitive methods to detect bacterial DNA may provide more information on the risk of bacterial translocation secondary to colonoscopy in dogs. ABSTRACT GI02 Low‐fat diet appears to be effective monotherapy in some dogs with protein losing enteropathy Marc Myers; Roger Hostutler; Stephen Martinez; Jonathan Shiroma MedVet The efficacy of a low‐fat diet as monotherapy or in combined therapy with prednisone for dogs with protein losing enteropathy (PLE) and evidence of lymphangiectasia remains poorly characterized, particularly in non‐Yorkshire Terriers. We hypothesized that clinical remission of PLE can be achieved via low‐fat diet monotherapy or in conjunction with prednisone in any canine breed. This was a prospective, observational cohort study of 14 dogs with PLE and ultrasonographic evidence of lymphangiectasia. All subjects were placed on dietary therapy and prednisone was added if initial response was deemed inadequate. Dogs were assessed and scored using the Canine Chronic Enteropathy Clinical Activity Index (CCECAI) at study enrollment and at 4 recheck examinations across a 6‐month study period, including a final recheck ultrasound at the last examination. Clinical and clinicopathologic variables were collected and dogs were divided into three outcome groups: (1) clinical remission on dietary therapy alone, the “DR” group; (2) clinical remission on dietary therapy plus prednisone, the “DP” group; and (3) treatment failure, the “DF” group. Eleven of 14 dogs (79%) were in clinical remission at the study end date (6 months post‐enrollment) based on a CCECAI score of <3, 6 from the DR group, and 5 from the DP group. Dogs from a variety of breeds were represented. Dogs in the DR group had higher median serum albumin (1.6 vs 1.2 g/dL, p = 0.11) and significantly higher median serum globulins (2.5 vs 1.7 mg/dL, p = 0.03) on presentation than dogs in the DP group. Four of 11 dogs in clinical remission also had ultrasonographic evidence of resolution of linear striations, 3 from the DR group and 1 from the DP group. Low‐fat diet appears to be an effective monotherapy in some dogs with PLE and lymphangiectasia. More severely clinicopathologically affected dogs may be less likely to respond to low‐fat diet monotherapy, but results must be interpreted cautiously due to low study enrollment. In dogs that do not respond to low‐fat diet monotherapy, the addition of prednisone can also lead to PLE remission although the durability of remission with either an exclusive low‐fat diet or low‐fat diet in conjunction with prednisone is unknown.   ABSTRACT GI03 Outcome for cats with chronic enteropathy diagnosed through endoscopic intestinal biopsies Kathryn Robb 1; Betty Chow2; Steve Hill1; Keith Richter1; Joerg Steiner3 1Veterinary Specialty Hospital by ETHOS Veterinary Health; 2VCA Animal Specialty & Emergency Center; 3Gastrointestinal Laboratory, Texas A&M University Inflammatory bowel disease (IBD) and alimentary small cell lymphoma (LSA) are common forms of feline chronic enteropathy (CE). Immunohistochemistry (IHC) and clonality testing (PCR for antigen receptor rearrangement; PARR) in conjunction with H&E may improve the accuracy of a diagnosis of LSA in patients when compared to H&E alone. There is evidence that using all three modalities (H&E, IHC, and clonality testing) leads to a more frequent diagnosis of alimentary small cell lymphoma than when the diagnosis is based on H&E alone. The goal of this study was to determine if a change in diagnosis, based on the use of IHC and clonality testing, correlates with patient outcome and survival time. A total of 62 cats with clinical signs of chronic enteropathy (>3 weeks duration) who were previously enrolled in a study and had undergone upper and lower gastrointestinal endoscopy with endoscopic biopsies submitted for H&E, IHC, and clonality testing were included in this study. All cases were categorized as “IBD,” “possible/probable LSA,” or “LSA” based on H&E alone. IHC and clonality testing further classified or reclassified cases as “IBD,” “LSA,” or “large granular lymphocyte lymphoma" (LGL). All owners were provided with an outcome survey via phone call and/or email. Also, medical records were reviewed to evaluate each patient's health status or cause of death, if known. Necropsy or additional surgical biopsy results were also reviewed if available. Of the 62 cats, 18 (29.0%) were alive at the time of the survey, while 30 (48.4%) were deceased, and 14 (22.6%) were lost to follow up. Estimated median survival times were determined by creating Kaplan‐Meier survival curves based on H&E diagnosis alone and for a diagnosis based on the combination of H&E and IHC/clonality testing. The estimated median survival times were 71.9 months for cats diagnosed as “IBD,” 15.7 months for cats diagnosed as “possible/probable LSA,” and 12.3 months for cats diagnosed as “LSA” when diagnosed by H&E alone. With the combination of H&E, IHC, and clonality testing, the estimated median survival times were 71.9 months for “IBD,” 22.8 months for “LSA,” and 0.33 months for “LGL.” Additional Kaplan‐Meier survival curves within each H&E diagnosis by IHC/clonality diagnosis were created. The addition of IHC and clonality testing to patients diagnosed with “IBD” on H&E did not show a significant change in survival time (p = 0.593). All patients diagnosed with “LSA” by H&E were confirmed to have “LSA” by IHC and clonality testing. Therefore, the survival time did not change for this group. Patients diagnosed with “possible/probable LSA" were either reclassified as “LSA” (n = 12) or “LGL” (n = 2). The patients with LGL had a short median survival time. However, the reclassified “LSA” patients had significantly longer survival time (p = 0.0001). Our results show that reclassification of feline patients with chronic enteropathy by addition of IHC and clonality testing does not influence the median survival time for patients diagnosed with “IBD” or “LSA” by H&E. IHC and clonality testing are useful for differentiating between “LSA” and “LGL” within the population of cats diagnosed as “possible/probable LSA" by H&E. This differentiation does make a significant difference in survival time. ABSTRACT GI04 Videofluoroscopic assessment of liquid sildenafil as a treatment for canine generalized megaesophagus Susan Mehain; Sarah Guess; Jillian Haines Veterinary Teaching Hospital, Washington State University Megaesophagus (ME) is characterized by dysmotility and dilation of the esophagus, causing regurgitation and carrying a poor prognosis. If it can be delivered to the stomach of dogs with ME, sildenafil may cause short‐duration relaxation of the gastroesophageal sphincter, thus improving clinical signs in dogs with ME via increased esophageal clearance. The objectives of this study were to determine if liquid sildenafil could be delivered to the stomach of dogs with ME and have significant effects on esophageal clearance, frequency of regurgitation, body weight, and perceived quality of life compared to no treatment or a placebo. In this blinded, randomized, crossover study, 10 healthy, client‐owned dogs, previously diagnosed with ME received either liquid sildenafil (1 mg/kg PO q12h) diluted to a total volume of 3–5 mL or a placebo of the same volume for 14 days, followed by a 7‐day washout, then the opposite treatment for 14 days. Esophageal clearance time was assessed prior to treatment (baseline), and on day 1 of each treatment period using videofluoroscopy performed over 30 minutes with dogs in an upright position. Dogs were assessed to determine passage of liquid treatment into the stomach, as well as for esophageal clearance of food after receiving liquid (at baseline) or liquid sildenafil/placebo followed by slurry, both containing iohexol contrast. Owners kept logs of regurgitation episodes for 2 weeks before, during the treatment periods, and during the washout periods. Movement of liquid into the stomach was assessed at baseline, and for each treatment, allowing 3 assessments per dog and 30 total assessments. Liquid moved into the stomach successfully 21/30 (70%) times (prior to slurry ingestion = 5, following slurry ingestion = 16) and failed to clear or mixed with the fed slurry 9/30 (30%) times. There were no significant differences found in esophageal clearance between untreated, placebo, or sildenafil treatment; regurgitation episodes between untreated, placebo, or washout periods; quality of life scores between untreated, sildenafil, or placebo; body weight after placebo; or esophageal clearance between untreated, placebo, or sildenafil treatment. Sildenafil did result in significant reductions in regurgitation episodes (p < 0.05) and increased body weight (p < 0.05) compared to untreated and placebo. Liquid sildenafil can be successfully delivered to the stomach of dogs with ME during the majority of feedings. Results indicate that there is potential for improved management of dogs with ME treated with long‐term liquid sildenafil. ABSTRACT GI05 Omeprazole induces reversible fecal dysbiosis in healthy dogs Rachel Pilla 1; Jan Suchodolski2; Jose Garcia‐Mazcorro2 ; Joerg Steiner2; Jonathan Lidbury2; Olivier Dossin3 1Texas A&M; 2Gastrointestinal Laboratory, Texas A&M University; 3Veterinary Clinic Advetia Omeprazole (OM) is a proton pump inhibitor that is commonly used in small animals. OM treatment has been reported to alter microbial populations in the GI tract in many species, including dogs. However, it is unknown whether these changes are reversible after the cessation of administration. Therefore, the goal of this project was to evaluate the impact of OM on the fecal microbiome in healthy dogs, both during and after omeprazole treatment. Stored samples from a research trial involving 8 healthy dogs receiving OM at 1.1 mg/kg per os q12hrs for 15 days. Fecal samples were collected twice before the beginning of treatment (D‐30 and D‐15), after the end of treatment (D15), and two weeks after the end of treatment (D29). DNA was extracted, and the qPCR‐based dysbiosis index (DI) was used to assess the fecal microbiota. The DI and abundance of select bacterial groups were compared across time points using 1‐way RM ANOVA. Significance was set as p < 0.05. The DI of the two baseline samples (D‐30 and D‐15) were not significantly different from each other (D‐30 mean: ‐2.9 ± 1.3; D‐15 mean: −3.0 ± 1.7; p = 0.994). After 15 days of OM administration, DI was significantly increased (mean: 1.8 ± 0.7) compared to D‐30 (p < 0.001). When individual genera were considered, the abundance of Turicibacter, a butyrate‐producing bacterium, was significantly decreased (p < 0.001) and that of Streptococcus was significantly increased (p = 0.002). The abundances of Faecalibacterium, E. coli, Blautia, Fusobacterium, and Clostridium hiranonis were not significantly affected. Two weeks after cessation of treatment, the mean DI (−2.0 ± 1.4) and the mean abundance of Turicibacter and Streptococcus were no longer significantly different from those of D‐30 (p = 0.645, 0.365, and 0.371, respectively). In summary, the administration of OM to healthy dogs for 15 days induced a significantly increased dysbiosis index. However, the dysbiosis index returned to the reference interval within two weeks after treatment discontinuation, indicating that OM‐induced dysbiosis is transient. The effect of OM on bacterial groups not assessed in this index remains to be determined. ABSTRACT GI06 Evaluation of feline gastrointestinal pH and transit times Naila J. Telles 1; Bradley Simon2; Aarti Kathrani3; Emily Gould1; Elizabeth Scallan2; Jonathan Lidbury1; Jörg Steiner1; Mark Papich4; M. Katherine Tolbert1 1Gastrointestinal Laboratory, Texas A&M University; 2Texas A&M University; 3Royal Veterinary College; 4North Carolina State University There are knowledge gaps regarding feline gastrointestinal (GI) physiology. As a consequence, veterinarians treat cats as they would a dog, which may be suboptimal. For example, acid suppressants known to be efficacious in dogs are only weakly efficacious in cats. Pharmaceutical companies have encountered difficulties developing oral medications for cats because they have relied on assumptions extrapolated from dogs. However, discrepancies identified between dogs and cats might be explained by differences in physiologic factors, such as intraluminal pH and transit times. Our study objective was to better characterize feline GI transit times as well as GI pH in both the fed and fasted states to determine if critical differences exist between species and contribute to oral drug failure in cats. After withholding food for 20 hours, six healthy, colony‐housed, research‐bred, spayed female cats had a Bravo pH capsule orally administered followed by 15 mL of water. Five hours after capsule administration, cats were meal fed by offering them their daily allowance of food for 1 hour and maintained in their colony housing. Fasted and fed GI pH, as well as transit times were recorded and compared to those reported for dogs using similar methodology. The median (range) transit times in minutes were: esophageal 10 (1–317), gastric 665 (1–2442), intestinal 1404 (1091–1731), and total transit time 2133 (1421–3850). The median (range) GI pH values were: esophageal 6.8 (6.1–7.3), gastric 2.8 (1.7–4.8), intestinal 8.4 (7.7–8.7), first‐hour duodenal 8.3 (7.7–8.7), and last‐hour large intestinal 8.5 (7.7–8.8). The median (range) fasted and fed gastric pH values were: 1‐hour pre‐prandially 3.7 (3.4–7.4), at time of feeding 3.9 (3.6–4.4), and 1‐hour post‐prandially 3.2 (2.4–4.1). Similar to dogs, GI pH and transit times were highly variable among cats and feeding did not exert a buffering effect on gastric pH. Replicate studies are underway to evaluate intra‐individual variability. Colony‐housed cats had higher intestinal pH and shorter total GI transit times compared to those previously reported in colony‐housed dogs. Based on these results, we believe that differences in intestinal pH and total GI transit times may be contributing reasons for differences in oral drug efficacy between dogs and cats. ABSTRACT GI07 Bacteria viability in stored canine feces for use in fecal microbiota transplantation Emerald Rodriguez; Mohammad Khattab; Jonathan Lidbury; Joerg Steiner; Jan Suchodolski Gastrointestinal Laboratory, Texas A&M University Fecal microbiota transplantation (FMT) is an emerging treatment option for dogs and cats with gastrointestinal (GI) disease. The goal of FMT is to re‐establish a stable microbial community from a healthy donor in the GI tract of the recipient. Currently, the optimal storage conditions for canine donor feces for use in FMT are unknown. The aim of this study was to determine the effect of different storage conditions on the viability of bacteria in canine fecal samples. Fecal samples from 10 healthy dogs were collected and aliquots of each sample were prepared. One aliquot was immediately treated with propidium monoazide (PMA), followed by DNA extraction to discriminate between DNA from viable versus non‐viable bacterial cells. The remaining aliquots were stored for either 1 week at 4°C or 3 months at −20°C or −80°C with or without the addition of 10% glycerol. After storage, these aliquots were also treated with PMA, followed by DNA extraction. The following bacterial groups were evaluated by qPCR in the feces: Faecalibacterium, Turicibacter, Blautia, E. coli, Streptococcus, Fusobacterium, and C. hiranonis. The abundance of viable bacteria in the stored aliquots was compared to the abundance of viable bacteria in aliquots immediately extracted using repeated measures ANOVA with Dunn's post‐test. Significance was set at p < 0.05. There was a significant decrease in viability of Fusobacterium for feces stored at all storage conditions compared to fresh feces (p < 0.002). For the remaining bacterial groups, storage at 4°C for 1 week did not cause a significant decline in bacterial viability compared to fresh feces (p > 0.108). After 3 months of storage, freezing with 10% glycerol was superior to freezing without glycerol, as no significant decline in viability was observed with this storage condition at either −20°C or −80°C. In conclusion, storage of fecal samples from healthy dogs resulted in a decline in viability of some bacterial groups. For short‐term storage, 4°C without additives appears sufficient, while for longer storage at either −20°C or −80°C, the addition of 10% glycerol is recommended. ABSTRACT GI08 Clinical effectiveness of hydrolyzed diets for chronic gastrointestinal signs in cats under primary veterinary care Aarti Kathrani; David Church; Dave Brodbelt; Camilla Pegram; Dan O'Neill Royal Veterinary College This study included a population of cats with chronic gastrointestinal (GI) signs in primary practice that were prescribed a commercial hydrolyzed diet. The study aimed to identify whether concurrent medical therapy alongside the diet was associated with differing clinical outcomes. Concurrent medical therapies included antibiotics and/or glucocorticoids used to manage their GI signs. Our study included 512,213 cats under veterinary care during 2016 in the UK from the VetCompass database. The medical records of all cats were searched using relevant search terms to identify cats with chronic GI signs receiving hydrolyzed diets. From 5,000 given hydrolyzed diets, 977 met the inclusion criteria. Of 697 cats that received the diet without concurrent antibiotic or glucocorticoid, 66% (457 cats) had a positive outcome, defined as not receiving antibiotic or glucocorticoid for GI signs at subsequent visits nor death from GI signs for a median follow‐up time of 818 days (range 184–5,279). In this subpopulation, the following factors increased the odds of a positive outcome in a multivariable model: cats 6 years old or younger when first prescribed the diet compared to cats that were older than 6 years (odd's ratio (OR): 1.55, 95% confidence interval (CI): 1.12–2.17, p = 0.009); cats that did not receive antibiotic prior to the hydrolyzed diet being first prescribed compared to those that did (OR: 1.53, 95% CI: 1.09–2.14, p = 0.013) and cats that did not receive glucocorticoid prior to the hydrolyzed diet being first prescribed compared to those that did (OR: 2.52, 95% CI: 1.50–4.23, p < 0.001). Of the 127 cats that received the diet with concurrent antibiotic and not glucocorticoid, 44% (56 cats) had a positive outcome, defined as not receiving additional antibiotic or glucocorticoid for GI signs at subsequent visits nor death from GI signs for a median follow‐up time of 946 days (range 186–3,599). In this subpopulation, cats 6 years old or younger when first prescribed the diet had increased odds of a positive outcome compared to cats that were older than 6 years (OR: 2.27, 95% CI: 1.09–4.75, p = 0.029). Of the 153 cats that received the diet with concurrent glucocorticoid with or without antibiotic, 35% (53 cats) had a positive outcome, defined as tapering and discontinuation of the glucocorticoid within 3 months without subsequent need of this medication or antibiotic for GI signs for a median follow‐up time of 1,082 days (range 213–3,888). In this subpopulation, the following factors increased the odds of a positive response in a multivariable model: cats 6 years old or younger when first prescribed the diet compared to cats that were older than 6 years (OR: 2.81, 95% CI: 1.37–5.75, p = 0.005) and cats that did not receive glucocorticoid prior to the hydrolyzed diet being first prescribed compared to those that did (OR: 2.07, 95% CI: 1.00–4.25, p = 0.049). Further studies are needed to determine whether the use of antibiotics or glucocorticoids prior to the use of a hydrolyzed diet with or without concurrent medical therapy affects the response to these diets or whether the results of our study are due to the prescribing habits of primary care veterinarians or the severity of the GI signs. ABSTRACT GI09 Diagnostic value of fecal bacteriologic culture and dysbiosis index in dogs with chronic diarrhea Melanie Werner 1; Jan Suchodolski2; Jonathan Lidbury2; Joerg Steiner2; Katrin Hartmann1; Stefan Unterer1 1Clinic of Small Animal Internal Medicine, Ludwig Maximilians University of Munich; 2Gastrointestinal Laboratory, Texas A&M University Although the clinical usefulness for fecal cultures has been determined to be low in human patients, bacteriologic culture of feces is still frequently performed in the diagnostic work up of dogs with diarrhea. Recently PCR‐based methodologies have been established to assess the fecal microbiome. This study aimed to assess the diagnostic yield of fecal cultures in dogs with chronic diarrhea. Fecal culture was performed in 18 dogs with chronic diarrhea and 18 healthy control dogs. Dogs were excluded if they received antibiotics or probiotics in the 4 weeks prior to presentation. Total bacteria and 7 bacterial groups (Faecalibacterium, Fusobacterium, Turicibacter, E. coli, Streptococcus, Blautia, C. hiranonis) were analyzed by qPCR in all dogs to calculate the fecal dysbiosis index (DI). Results were compared between diseased and healthy dogs. Exact χ2 test was used to compare categorical variables and Mann‐Whitney test to compare the DI. Fecal culture failed to detect any significant difference in the presence of specific enteric pathogens as well as in the assessment of the composition of the gram‐negative and gram‐positive flora (p ≥ 0.289). However, the DI was significantly different between dogs with chronic diarrhea (mean [SD]: 0.94 [3.80]) and the healthy control group (mean [SD]: −2.96 [2.77]; p = 0.0002). In contrast to the PCR‐based fecal dysbiosis index, fecal cultures have a low value to differentiate between normo‐ and dysbiosis. Thus, fecal cultures do not appear to be useful to identify causative agents and to guide treatment decisions in dogs with chronic diarrhea. ABSTRACT GI10 The effect of combined carprofen and omeprazole administration on gastrointestinal permeability and injury in dogs Susan M. Jones 1; Ann Gaier1; Hiroko Enomoto1; Patricia Ishii2; Rachel Pilla2; Josh Price3; Jan Suchodolski2; Joerg Steiner2; Mark Papich1; Kristen Messenger1; M. Katherine Tolbert2 1College of Veterinary Medicine, North Carolina State University; 2College of Veterinary Medicine & Biomedical Sciences, Texas A&M University; 3University of Tennessee Proton pump inhibitors (e.g., omeprazole) are commonly administered concurrently with nonsteroidal anti‐inflammatory drugs (NSAIDs; e.g., carprofen) to reduce the risk of injury to the gastrointestinal (GI) tract. However, evidence to support this practice is weak, and it may exacerbate NSAID‐induced enteropathy. Our objective was to evaluate the effect of carprofen alone or with omeprazole in dogs. We hypothesized that the co‐administration of omeprazole and carprofen would significantly increase GI permeability and dysbiosis index compared to no treatment or carprofen alone. Serum LPS, plasma iohexol, fecal dysbiosis index, and fecal calprotectin concentration were used to assess GI permeability and injury in six healthy, adult Beagle dogs in a prospective, 3‐period design. In the first seven‐day sham period, dogs received no intervention (baseline). During the second period, dogs received 4 mg/kg of carprofen q24hrs orally for seven days. In the third period, dogs received 4 mg/kg of carprofen q24hrs and 1 mg/kg of omeprazole q12hr orally for seven days. GI permeability assays were performed at the end of all three periods. Data were analyzed using two‐within subjects factor repeated measures mixed‐model ANOVA with Tukey‐Kramer post hoc tests (p < 0.05). Serum LPS and plasma iohexol concentrations did not differ between treatments. Fecal calprotectin concentrations significantly differed between treatments (p = 0.034). The fecal dysbiosis index varied over time based on the treatment received (p = 0.031). Co‐administration of omeprazole and carprofen significantly increased fecal dysbiosis index and calprotectin in dogs. Although more studies are warranted, these results suggest that omeprazole can worsen NSAID‐induced enteropathy in otherwise healthy dogs. ABSTRACT GI11 Objective evaluation of deglutition in healthy cats using a free‐feeding videofluoroscopic swallow study protocol Megan E. Grobman 1; Elizabeth Luciani2; Carol Reinero2 1Auburn University; 2University of Missouri Background: Videofluoroscopic swallow studies (VFSS) represent the criterion standard for diagnosis of cause of dysphagia in veterinary medicine. Physiologically relevant objective VFSS parameters in healthy cats are lacking. The absence of species‐specific swallowing parameters represents a significant limitation in assessing cats with dysphagia. Objectives/Hypothesis: Using a standardized unrestrained, free‐feeding VFSS protocol, the study aims were to apply objective swallow metrics to healthy cats and to determine species differences by comparing to objective swallow metrics in healthy dogs. We hypothesize that species‐specific swallowing parameters can be identified by free‐feeding VFSS in healthy cats. Animals: Healthy adult cats (n = 13) and dogs (n = 24). Methods: Free‐feeding VFSS utilized fourteen objective metrics of swallowing compared across species and three food consistencies (liquid, puree, and kibble). Objective VFSS metrics included assessment of the oral, pharyngeal, and esophageal stages of swallow. Differences in species and consistency were evaluated by Mann‐Whitney Rank Sum Test and One‐way ANOVA on Ranks respectively with a p < 0.05 significance level. Results: VFSS features attributed to pathologic states, including reflux (n = 2) and macro‐aspiration (n = 1) were observed in healthy, asymptomatic cats. Statistically significant differences were detected between species (≥5 metrics) and consistencies (≥5 metrics) (p < 0.05). Conclusions: Free‐feeding VFSS data was successfully collected in healthy cats with results inclusive of reflux and macro‐aspiration. Significant differences with food consistency support the need for standardized recipes for consistent evaluation. Objective swallowing metrics are not directly translatable across species, requiring species specific cut‐offs when using objective swallowing metrics. ABSTRACT GI12 Mycophenolate mofetil effect on the gastrointestinal microbiome in dogs Kenjiro Fukushima 1; Jason Gagne2; Jonathan Lidbury3; Lia McCoy4 ; Jorg Steiner3; Jan Suchodolski3; Michael Lappin4 1Veterinary Teaching Hospital, Small Animal Medicine, Colorado State University; 2Purina Nestle; 3Texas A&M University; 4Colorado State University Mycophenolate mofetil (MMF) is an effective immunosuppressant in dogs, but gastrointestinal (GI) toxicity is common. Based on our previous study, 24.4% of 135 client owned dogs experienced GI toxicity (median dose 17.5 mg/kg/day, median time to onset 10 days). Postulated mechanisms for MMF induce GI toxicity include GI dysbiosis, direct cellular toxicity from MMF metabolites, and impaired proliferation of enterocytes. In one study, antibiotics lessened signs of GI toxicity induced by MMF. Based on these data, our hypothesis was that MMF induced GI toxicity in dogs is due to intestinal dysbiosis. The purpose of this study was to determine MMF effects on clinical signs and the fecal microbiome. A total of 15 young adult beagles were assigned into 2 groups (control: n = 6, MMF: n = 9). Dogs in MMF group 2 were administered MMF (20 mg/kg/day) for 14 days. Appetite, attitude, dehydration, and fecal consistency were scored by blinded personnel until day 28 and fecal microbiome was analyzed using quantitative PCR on samples from days 0, 14, and 28. The MMF group had significantly higher fecal scores than the control group and the MMF group showed significantly higher fecal scores during treatment period compared to baseline. On microbiome analysis, no significant differences were seen between the MMF and control groups. Based on our data, MMF induced diarrhea was common but was not associated with dysbiosis as determined with the here analyzed bacterial taxa. Further study is warranted to determine the cause of MMF induced GI toxicity and whether it can be prevented. ABSTRACT GI13 Effect of fasting on the gastrointestinal panel in healthy dogs Alexander Saver 1; Jörg Steiner2; Scott Hetzel3; Jessica Pritchard1 1School of Veterinary Medicine, University of Wisconsin‐Madison; 2College of Veterinary Medicine, Texas A&M University; 3Department of Biostatistics and Medical Informatics, University of Wisconsin‐Madison The gastrointestinal panel, comprising of serum concentrations of cobalamin (vitamin B12), folate (vitamin B9), pancreatic lipase immunoreactivity (cPLI), and trypsin‐like immunoreactivity (cTLI), is an essential tool in the diagnosis and management of small intestinal and pancreatic disease in dogs. However fasting requirements for these tests from commercial laboratories range from 6–18 hours and are not evidence‐based. Unnecessary fasting in veterinary patients results in reduced patient welfare, logistic challenges for clinicians and, in the acute hospital setting, delayed return to feeding. The objective of this study was to determine evidence‐based fasting requirements for analytes part of the gastrointestinal panel in clinically healthy dogs. We hypothesized that there would be no clinically relevant difference in these analytes between a commonly utilized overnight fast (12 hours) and various postprandial timepoints (1, 2, 4, & 8 hours post‐feeding). Eleven healthy dogs with no history of gastrointestinal disease completed the study protocol. Dogs were fasted overnight (12 hours) and a baseline serum sample was collected. They were then fed and repeated serum samples were collected at 1, 2, 4, & 8 hours postprandially. Analytes in these samples were compared to baseline using a linear mixed‐effects model. Cobalamin was statistically significantly decreased at 4 hours (472 pg/ml; p = 0.0080) and 8 hours (476 pg/ml; p = 0.0040), compared to 12 hours (526 pg/ml) postprandially, but this difference was not clinically relevant. No difference was seen for serum folate, cPLI, or cTLI concentration. In healthy dogs, fasting did not result in clinically relevant differences in gastrointestinal panel analytes. This evaluation should be repeated in dogs with gastrointestinal disease to determine if fasting is necessary in this population of dogs. ABSTRACT GI14 Adverse effects and impact on microbiome in healthy dogs treated with omeprazole Kathryn Hogan; Thurid Johnstone; Caroline Mansfield University of Melbourne The primary aim of this study is to identify the impact of omeprazole on the fecal microbiome of dogs using the fecal dysbiosis index (FDI). Secondary aims were to ascertain if any adverse clinicals signs occurred because of omeprazole use and if any changes were dose dependent. Twenty healthy, client‐owned dogs, over 1 year of age with a normal body condition score, receiving a consistent diet and regular parasite control were recruited to participate in a prospective, randomized trial. Additional inclusion criteria were that dogs had not received any antibiotics, corticosteroids, or non‐steroidal anti‐inflammatories in the preceding 3 months, and did not have any history of significant or recurrent gastrointestinal disease. Other long‐term medications including fluoxetine, zylkene, and oclacitinib maleate were permitted. Dogs were randomly allocated via Excel® spreadsheet random distribution function, to either a 1 mg/kg or 0.5 mg/kg group. Dogs received omeprazole twice daily for 7 days, then once daily for a further 7 days. Fecal collection was performed by the owners or the principal investigator at day 0 and at the end of weeks 1, 2, 4, and 6; samples were immediately refrigerated and transported chilled to the University of Melbourne, mixed with 95% ethanol and stored before being shipped on ice to the University of Texas A&M for FDI testing. Owners also kept a daily log during the first 2 weeks of including fecal scoring, using the Purina fecal index chart. Twenty dogs commenced the trial, however, only 13/20 completed the full 6 weeks of monitoring. Of those that did not complete the study 6/7 were withdrawn in the first week due to adverse effects. A further 1 dog discontinued the trial after finishing the first 2 weeks of omeprazole due to requirement for NSAIDs treatment. Of those dogs withdrawn for adverse effects 3/6 had diarrhea only, 2/6 had both diarrhea and vomiting, and 1/6 had vomiting only. A further 2/13 dogs that did complete the trial had observable changes in fecal consistency and an additional 2/13 had 1 or more episodes of vomiting while receiving omeprazole. In total 10/20 dogs commencing the trial showed evidence of adverse effects; 6/10 of the dogs that had adverse effects received omeprazole at 1 mg/kg. The most substantial change in FDI was noted at the end of the first week of omeprazole dosing with 7/15 dogs in dysbiosis and 12/15 dogs trending towards dysbiosis as defined by a positive increase from individual baseline, in FDI score. Significant inter‐individual variation did occur. Due to the large drop‐out rate as a result of adverse effects, the high treatment group was not continued and so there are insufficient numbers to determine if statistically the higher dose leads to a greater dysbiosis than the lower dose. While there was significant intra‐individual variation, this study demonstrates that the use of twice daily omeprazole in healthy adult dogs causes substantial changes in the fecal dysbiosis index with 12/15 dogs trending towards dysbiosis. Additionally, it highlights the frequency of adverse effects with 50% of dogs in this trial developing vomiting, diarrhea, or both. Omeprazole is frequently used by veterinarians for the management of vomiting and diarrhea, even in the absence of suspected gastric or esophageal ulceration. Given the findings of clinical and microbiome impacts in our study of healthy dogs, treatment with omeprazole in dogs with gastrointestinal signs may inadvertently prolong recovery times and potentially worsen outcome. Further investigation is required to confirm if similar changes are noted in unwell dogs, and if there are longer‐term metabolic impacts in healthy dogs. ABSTRACT GI15 Defining healthy. The utility of building a companion animal fecal microbiome reference dataset Dawn D. Kingsbury 1; Jess Jarett1; Carlton Osborne1; Alex Martin1; Jonathan Eisen2; Holly Ganz1 1AnimalBiome; 2UC Davis We conducted a participatory research project on the microbiome of cats and dogs where participants submitted fecal samples for bacterial characterization, and built a biobank of >5,800 samples. From these, we curated a subset of 274 fecal samples from apparently healthy cats and dogs. We used this dataset to determine if there is a core fecal microbiome in pet dogs and cats, and whether it might provide a useful frame of reference for companion animal medicine. Fecal samples were submitted and participants answered detailed questionnaires about the pet's health. The microbiome was characterized at the genus level with Illumina sequencing of PCR amplified 16S rRNA genes. From this dataset, we selected 83 cats and 191 dogs as healthy reference animals. Inclusion criteria included a healthy body condition score, the absence of any clinical signs, no diagnosis of disease or behavior problem, and no antibiotic treatment in the preceding twelve months. Ages ranged from 1–12 yr for cats and from 1–11 yr for dogs. Because pets were not examined by a veterinarian for this project, we implemented more conservative screening criteria to eliminate as many occultly unhealthy animals as possible. All genera present in at least 45% of healthy dogs (n = 15 genera) or 66% of healthy cats (n = 17 genera) were considered part of the normal core microbiome (n = 14 shared genera). The distribution of specific genera of veterinary importance was also assessed, including Escherichia‐Shigella. Low abundances of these taxa are common in healthy animals, and high abundances are often observed in animals with clinical signs. Median values best reflected the most frequently observed relative abundances, and low and high thresholds for each genus were based on the upper and lower 2.5th and 10th percentiles of the normal range for the genus. In dogs, a median of 87.9% (±9.88%) of the total microbiome is represented by the core microbiome of 15 genera, and in cats 73.8% (±9.70%) of the total microbiome is represented by the core microbiome of 1 7 genera. Next, we demonstrated the relevance of the normal taxa ranges as defined by the healthy reference dataset by comparing the clinical signs of animals within the normal range and above the normal range for Escherichia‐Shigella from the entire database. Both cats and dogs with Escherichia‐Shigella values in the 90th percentile or above (4.4% for cats, 5.4% for dogs) were significantly more likely to have diarrhea reported than animals below the 90th percentile (n = 85 and 64.7% vs. n = 565 and 43% for cats, p = 0.0003; n = 476 and 50.2% vs. n = 1356 and 30.5% for dogs, p = 2.5 × 10–14, Fisher's exact test). This research supports the presence of a taxonomically defined core microbiome in healthy pet cats and dogs. Our discovery‐based approach determines which bacteria are contributing to imbalances, enables identification of new biomarkers of disease, and can help inform therapeutic recommendations. ABSTRACT GI16 Relationship between anemia, iron status, and cobalamin status in cats with chronic gastrointestinal disease Maria Jugan 1; Adam Hunt2 1College of Veterinary Medicine, Kansas State University; 2College of Veterinary Medicine, University of Tennessee Anemia is common in humans with chronic gastrointestinal disease, resulting from gastrointestinal bleeding, iron deficiency, and hypocobalaminemia, and increases all‐cause mortality in cats. Objectives of this study were to investigate prevalence of anemia in cats with chronic gastrointestinal disease and association with cobalamin and iron status. Twenty client‐owned cats with chronic (≥4 weeks) gastrointestinal disease were enrolled prospectively. CBC, serum iron, ferritin, total iron binding capacity (TIBC), serum cobalamin, and serum methylmalonic acid (MMA) tests were performed. The Mann‐Whitney U test was used to compare cats with low vs. normal iron and normal vs. elevated MMA. Spearman's test was used to correlate MMA, iron, and CBC parameters. Prevalence of anemia, iron deficiency, and elevated MMA were 15%, 35%, and 40%, respectively. Iron deficiency was characterized as functional based on decreased iron, decreased percent saturation, and normal ferritin. Hematocrit (p = 0.03), reticulocyte hemoglobin content (CHr; p = 0.02), and ferritin (p < 0.01) were lower in cats with decreased iron vs. normal iron. TIBC was lower in cats with increased MMA vs. normal MMA (p = 0.02). MMA negatively correlated with hematocrit (r = −0.45). Iron positively correlated with hematocrit (r = 0.5), MCV reticulocyte (r = 0.52), CHr (r = 0.71), % Sat (r = 0.79), and ferritin (r = 0.45). Functional iron deficiency was common in cats with chronic gastrointestinal disease. Cats with lower iron and higher MMA had lower hematocrit. Future studies are needed to determine impact of iron status on survival in cats with chronic gastrointestinal disease. ABSTRACT GI17 Metronidazole‐induced dysbiosis alters fecal but not serum amino acid profiles in healthy dogs Amanda B. Blake 1; Frédéric Gaschen2; Erin Olson2; Jonathan Lidbury1; Jörg Steiner1; Jan Suchodolski1 1Gastrointestinal Laboratory, Texas A&M University; 2School of Veterinary Medicine, Louisiana State University Amino acids are mainly absorbed in the proximal small intestine and can affect a multitude of metabolic processes in the host, such as protein synthesis, formation of neurochemical messengers, and important energy metabolism pathways. Unabsorbed amino acids can be fermented by gut bacteria. Numerous studies have shown that oral antibiotics affect the gut microbiota. With growing interest in the role of amino acids in gastrointestinal disease and the high prevalence of antibiotic usage in these patients, it is important to understand how antibiotics affect amino acid profiles. The objective of this study was to determine if metronidazole‐induced dysbiosis alters serum or fecal amino acid profiles in healthy dogs. Baseline fecal and serum samples were collected from 16 healthy pet dogs (D0), that were subsequently treated with metronidazole at 15 mg/kg per os q12h for 14 days. Additional serum samples were collected on day 14 after the last dose of metronidazole (D14) and on day 42 (D42). Naturally passed fecal samples were collected on days 7, 14, 28, and 42 (D7, D14, D28, D42). Fecal and serum samples were analyzed for untargeted metabolomics analysis. Kruskal‐Wallis tests followed by Dunn's multiple comparison tests were used to assess differences compared to baseline. Spearman's rank adjusted by Benjamini & Hochberg FDR were used to analyze correlations between fecal amino acid abundance and fecal bacterial taxa obtained by 16S rRNA gene sequencing. Statistical significance was set at q < 0.05. Nine essential and 10 non‐essential proteinogenic amino acids were identified by untargeted metabolomics. None of the amino acids were altered in the serum during or after metronidazole administration (D14 or D42) when compared to baseline values. In the feces, lysine was significantly decreased on D14 (q = 0.041) and tyrosine was significantly decreased on D7 (q = 0.002) and D14 (q = 0.041). Additionally, fecal glycine, glutamic acid, and cysteine were significantly increased during metronidazole administration (q < 0.029). Across all time points, the abundance of Enterococcus and Dorea correlated with tyrosine (ρ = −0.702 and ρ = 0.645, respectively; q < 0.001), and Streptococcus abundance positively correlated with glutamic acid (ρ = 0.612; q < 0.001). Significant alterations of some amino acids were observed in the feces, but not in serum during metronidazole‐induced dysbiosis in healthy dogs. This suggests that short‐term gastrointestinal microbial dysbiosis caused by metronidazole administration does not affect serum amino acid metabolism in healthy dogs. ABSTRACT GI18 Chronic enteropathy has bigger impact than diet or country of residence on canine fecal dysbiosis Rachel Pilla 1; Melissa Guard1; Stefan Unterer2; Karin Allenspach3; Linda Toresson4; Aurelien Grellet5; Leda M. O. Barros6; Joerg Steiner7; Jonathan Lidbury7; Jan Suchodolski7 1Texas A&M University; 2Ludwig Maximilian University of Munich; 3Iowa State University; 4Evidensia Specialist Animal Hospital; 5NeoCare, UMR INRA/ENVT, University of Toulouse; 6FMVZ, University of Sao Paulo; 7Gastrointestinal Laboratory, Texas A&M University Alterations of the gut microbiome are often present in dogs with chronic enteropathies (CE). A recently published qPCR‐based assay termed the fecal dysbiosis index (DI) can assess fecal dysbiosis in dogs. While previous metagenomic studies have revealed that some changes in gastrointestinal microbiome composition can be induced by diet, it is unclear how those changes impact the keystone bacteria assessed by the DI. The GI microbiota in humans has also been reported to be affected by country of residence, a factor which has not yet been investigated in dogs. Therefore, the goal of this study was to evaluate the impact of CE, dietary macronutrient composition, and country on the fecal DI. A total of 271 fecal samples were selected from previous clinical trials, including 185 from healthy control (HC) dogs from Brazil, Finland, Germany, Italy, Sweden, and the USA, and 86 dogs with CE from Brazil, France, Sweden, UK, and the USA. DNA was extracted and the fecal DI was determined. Data on diet at the time of sampling was available for 76 HC and 45 CE dogs. Mann‐Whitney and Kruskal‐Wallis tests with multiple comparisons were performed to compare the DI between groups and countries, respectively. The relationship between the proportion of macronutrients (protein, fat, and carbohydrate percentages of metabolizable calories, fiber as percentage of dry matter) and fecal DI were evaluated with Spearman's rank correlation. Statistical significance was set at p < 0.05. Dogs with CE had a significantly higher DI (median: 3.2) compared to HC (median: −3.7, p < 0.001). When dietary factors were considered, the fecal DI was not significantly correlated with dietary protein (CE p = 0.948; HC p = 0.316), fat (CE p = 0.887; HC p = 0.461), or carbohydrate (CE p = 0.448; HC p = 0.503) content. Dietary fiber percentages also did not correlate with DI in CE (p = 0.156) or HC (p = 0.590). While dietary composition did not affect fecal DI, when individual bacterial taxa were considered, two correlations were identified within the CE groups. Dietary fat showed a weak positive correlation with the abundance of Turicibacter (p = 0.019, r = 0.359), and carbohydrate content showed a weak positive correlation with Fusobacterium abundance (p = 0.016, r = 0.369). Country had no influence on DI within the group of dogs with CE (p = 0.065), and within HC, only dogs from Italy had a significantly higher DI (median: 0.2) compared with other countries (median for Brazil: −2.3; Finland: −4.0; Germany: −4.1; Sweden: −4.5; and USA: −3.9; p = 0.002). In conclusion, dogs with CE had a significantly higher DI than HC, the median of which was outside of the reference interval. While the abundance of individual bacterial taxa were weakly correlated with dietary factors, a composite index such as the DI is less susceptible to such effects. Indeed, we found no correlation between dietary protein, fat, or carbohydrate percentages of metabolizable calories, or dietary fiber percentages, with fecal DI. Interestingly, fecal samples from healthy dogs living in Italy were different than all other countries, which possibly arose from factors unaccounted for in this study. Overall, these factors are unlikely to affect the use of the DI as a diagnostic and monitoring tool. ABSTRACT GI19 Comparison of the fecal microbiota between healthy dogs and dogs with diabetes mellitus Fabio Alves Teixeira 1; Bettina Di Donato1; Patricia Eri Ishii2; Thaila Putarov3; Aulus Carciofi3; Juliana Jeremias4; Mariana Queiroz1; Cristiana Pontieri4; Joerg Steiner2; Jonathan Lidbury2; Jan Suchodolski2; Marcio Brunetto1; Marcia Gomes1 1School of Veterinary Medicine and Animal Science, University of São Paulo; 2College of Veterinary Medicine and Biomedical Sciences, Texas A&M University; 3School of Agricultural and Veterinarian Science, Sao Paulo State University; 4Nutritional Development Center, Grandfood Industry and Commerce LTD (Premier Pet) There is evidence that both humans and mice with diabetes mellitus (DM) have gastrointestinal dysbiosis. This study aimed to compare the fecal microbiota of diabetic dogs and healthy control dogs. Twenty‐one dogs were selected for this study: 8 healthy adult beagles from a research facility and 13 privately owned diabetic dogs of various breeds. The criteria for inclusion of diabetic dogs included: glycemia fluctuation between 90 and 300 mg/dL, body condition score (4–5/9), and same body weight for 60 days. Diabetic dogs received a high‐fiber diet to facilitate glycemia control for 60 days and healthy beagles received the same diet for 45 days prior to assessment. Fecal samples were collected and were immediately frozen at −80°C. Microbiota was assessed with 16S rRNA gene sequencing and a qPCR based fecal dysbiosis index (DI). The abundance of bacterial groups and DI between the two groups of dogs were compared using Welch's two sample t‐tests with significance set at p < 0.05. There was no significant difference in the DI between diabetic (mean: −0.69 ± 4.34) and healthy beagles (mean: −1.02 ± 1.76; p = 0.81). Sequencing data revealed that diabetic dogs had lower abundance of Lactobacillus gender bacteria and a higher abundance of Ruminococcus when compared to healthy dogs. This was the first dog microbiota profile study comparing healthy and diabetic dogs with a standardized diet. 16S rRNA gene sequencing showed similar findings to those from studies of humans and mice in that certain bacterial genera were altered in diabetic dogs. Further research is needed to determine if these alterations in the gastrointestinal microbiota play a role in the pathogenesis of diabetes in dogs. ABSTRACT GI20 Understanding the failure of oral acid suppressants in cats Katie Tolbert 1; Desola Odunayo2; Phillip Ryan2; Shanna Hillsman2; Gina Galyon2; Silke Hecht2; Joerg Steiner1; Josh Price2 1Texas A&M University; 2University of Tennessee A sustained increase in gastric pH is central to the successful treatment of upper gastrointestinal (GI) erosion/ulceration and esophagitis in cats. Thus, acid suppressant drugs, such as proton pump inhibitors (PPI; e.g., omeprazole) and histamine‐2 receptor antagonists (e.g., famotidine) are commonly prescribed. The requirement for frequent administration and the need to give omeprazole before a meal in cats likely leads to disruption of the human‐animal bond, poor owner adherence, and treatment failure. Thus, veterinarians are increasingly prescribing newer PPIs that are longer acting and can be given with food. The efficacy of these novel gastroprotectants has heretofore not been comparatively evaluated and described. Accordingly, our central objective was to evaluate the efficacy of orally administered esomeprazole, lansoprazole, and dexlansoprazole in increasing the intragastric pH of cats. In a randomized, crossover study, 12 cats received 1 mg/kg esomeprazole or lansoprazole or 6 mg/kg dexlansoprazole orally twice‐daily for 4 days. Intragastric pH was compared within and between treatments over time using repeated measures mixed model ANOVA. Significant differences in mean percentage time (MPT) intragastric pH ≥3 were found between treatments (p = .002) and over time (p = .039) but not treatment by time. Post hoc tests revealed that cats treated with lansoprazole were found to have lower MPT intragastric pH ≥3 than cats treated with dexlansoprazole or esomeprazole (p = .027, for each). Only esomeprazole achieved the pH goal for the treatment of duodenal ulceration as defined for people and this effect was not observed until treatment day 4. The difference between cats and dogs in their response to oral acid suppressants might be explained by differences in feline GI pH and motility and their impact on drug delivery. Preliminary data from a subsequent study on feline gastric pH and gastrointestinal transit times will be included to support this conclusion. ABSTRACT GI21 Phenotypic and functional characterization of adult intestinal organoids from dogs with inflammatory bowel disease Sichao Mao 1; Chelsea Iennarella‐Servantez1 ; Todd Atherly1; Dana Borcherding1; Yoko Ambrosini2; Laura Kurr1; Agnes Bourgois‐Mochel1 ; Yeon‐Jung Seo1; Jonathan Mochel1; Karin Allenspach1; Albert Jergens1 1Iowa State University; 2University of Texas at Austin Canine inflammatory bowel disease (IBD) refers to a group of chronic gastrointestinal (GI) disorders of unknown cause and pathogenesis. With the aim of modeling spontaneous GI disease in dogs and humans, intestinal stem cell (ISC)‐derived organoids are emerging as a promising ex vivo system for studying IBD pathogenesis. Previous studies from our laboratory have validated the cultivation of 3D canine intestinal organoids (enteroids and colonoids) from crypt base columnar (CSC) cells. In collaboration with the US FDA, the aim of this investigation was to compare the similarities and differences in phenotypic and functional characterization between organoids derived from healthy dogs and dogs with IBD. We chose to focus on ileal‐derived enteroids as a translational ex vivo model due to their unique role in drug absorption and as a primary site of human IBD (i.e., Crohn's ileitis) development. ISCs isolated from endoscopic biopsies of two healthy dogs and two dogs with active IBD were differentiated into intestinal organoids. Ileal organoids and matching primary tissues were probed by RNA in situ hybridization and immunohistochemistry for phenotypic changes in IBD. A panel of six phenotypic markers identified different epithelial cell lineages (LGR5: intestinal stem cell, ALP: enterocyte, PAS: goblet cell, NEUROG3: enteroendocrine cell), evidence of epithelial barrier integrity (ZO‐1) and cell proliferation (Ki‐67). Phenotypic marker expression was then quantitated by light microscopy and ImageJ. In addition, functional features of IBD organoids were investigated by cystic fibrosis transmembrane conductance regulator (CFTR) organoid swelling assay to measure chloride‐channel‐water conductance across epithelial cells. Forskolin‐induced swelling of enteroids was quantitated using an inverted microscope and ImageJ. The increase in surface area after forskolin treatment in organoids from dogs with IBD was compared to results obtained in organoids derived from healthy dogs. Data were analyzed using R version 3.5. Pairwise comparisons were performed to determine group differences. Statistical significance level was set at p < 0.05. IBD organoids showed different phenotypic features as compared to healthy organoids, including increased expression of ALP, NEUROG3, LGR5, ZO‐1, and PAS; however, Ki‐67 expression was found to be decreased in IBD enteroids. Among these markers, expression of NEUROG3 and PAS exhibited significant difference (p < 0.05). Furthermore, similar trends in phenotypic changes were observed between IBD organoids and inflamed primary tissues for LGR5, NEUROG3, and ZO‐1 expression. Forskolin significantly (p < 0.05) increased surface area of IBD organoids after 1 and 4 hr vs. controls indicating functional CFTR in IBD organoids. To conclude, this study provides the first report of phenotypic changes in intestinal organoids from dogs with IBD. Overall, our results show that IBD organoids show different phenotypic features as compared to healthy organoids. In addition, our study shows that ileal organoids derived from dogs with IBD recapitulate both the phenotypic and physiological features of diseased tissue compared to healthy tissue, demonstrating its utility as an ex vivo model for investigating pathomechanisms and pharmacotherapy in dogs with IBD.   ABSTRACT GI22 Increased mean platelet volume in dogs with canine parvoviral enteritis Monique Engelbrecht 1; Amelia Goddard2; Vanessa McClure2 ; Paolo Pazzi2 1Onderstepoort Veterinary Academic Hospital, University of Pretoria; 2University of Pretoria Bacterial translocation from the damaged intestinal tract, reported in canine parvoviral (CPV) enteritis, is thought to be responsible for the systemic inflammatory response resulting from coliform septicemia, which could ultimately progress to septic shock and death. Alterations in platelet indices, specifically mean platelet volume (MPV), are a consistent finding in critically ill people and dogs with and without sepsis. Increased MPV has been reported to be an indirect indicator of platelet activation and of bone marrow response in people and dogs with sepsis. The study aim was to compare admission MPV and platelet volume distribution width (PVDW) in dogs with CPV enteritis to that of healthy aged matched control dogs. Forty‐eight dogs with CPV enteritis and 18 healthy age‐matched control dogs were included. CPV infection was confirmed with electron microscopy and concurrent blood‐borne infections were excluded using PCR. EDTA whole blood samples were analyzed on an automated cell counter, ADVIA 2120, within 30–60 minutes from collection. There was no significant difference for platelet count between the groups. The MPV for CPV infected dogs (median: 14.0; IQR: 12.2–15.1) was significantly higher compared to controls (11.3; IQR: 10.3–13.1, p = 0.002). The PVDW for CPV infected dogs (66.9; IQR: 64.2–68.8) was significantly higher compared to controls (63.3; IQR: 60.2–65.1, p < 0.001). These findings suggest that significant platelet activation is present in dogs with CPV enteritis which may play a role in the disease outcome, similar to people with sepsis. Further studies are required to investigate the prognosticating ability of MPV in dogs with CPV enteritis. ABSTRACT GI23 Proteomic characterization of feline gastric fluid to detect protein biomarkers of reflux and aspiration Megan E. Grobman 1; Hansjorg Rindt2; Carol Reinero2 1Auburn University; 2University of Missouri Background: Reflux and aspiration of gastric contents are sources of respiratory disease in humans despite 50% of healthy adults aspirating without apparent clinical consequence. In cats, analogous information is lacking. Understanding the frequency of reflux and aspiration in healthy cats is critical to determining their significance in patients with respiratory disease. Objectives/Hypothesis: To investigate the prevalence of extra‐esophageal reflux (EER) in healthy cats using proteomic characterization of feline gastric fluid and orphopharnygeal (OP) swabs before and after feeding. We hypothesize that healthy cats will have evidence of EER characterized by detectable gastric and intestinal proteins on OP swabs. Animals: 17 healthy companion and research cats. Methods: Gastric fluid (GF) (n = 4) and OP swabs (n = 13), pre‐ and 30 min post‐feeding, were evaluated by liquid chromatography mass spectrometry (LCMS). Differential protein abundance (DA) was evaluated by Student T test (p < 0.01). Coefficients of variation were calculated for proteins with DA. Results: Individual proteins (n = 1802) were identified in OP swabs. Significant DA was found (p < 0.01): pre‐feeding vs. post‐feeding (n = 126), GF vs. pre‐feeding (n = 267), GF vs. post‐feeding (n = 217). Marked between‐cat variation was observed for proteins with DA. Proteins specific to the stomach or intestines were found in OP swabs from all cats with no differences between pre‐ and post‐feeding samples. Conclusions: Gastrointestinal proteins in the OP of healthy cats suggests EER occurs as part of their swallowing physiology. Quantification of GI proteins in the OP may be necessary to determine pathology rather than the presence or absence of such markers. ABSTRACT GI24 Assessment of intestinal permeability in dogs with chronic enteropathy Patricia Eri Ishii 1; Ana Rita Carvalho Pereira2; Fabio Teixeira3; Robert Kyle Phillips1; Rafael De Miranda4; Franz Yoshitoshi4; Paula Giaretta5; Ricardo Duarte6; Jonathan Lidbury7; Joerg Steiner7; Jan Suchodolski7 1Texas A&M University; 2GastroVet; 3School of Veterinary Medicine and Animal Science, University of Sao Paulo; 4Endoscopet Medicina Veterinaria; 5Universidade Federal de Minas Gerais; 6Faculdades Metropolitanas de Sao Paulo; 7College of Veterinary Medicine and Biomedical Science, Texas A&M University Increased IP has been hypothesized to play a role in the pathogenesis of chronic enteropathy (CE) in dogs. However, due to a lack of an optimal marker, the mechanism by which IP affects or influences CE in dogs remains unclear. Recently, iohexol has been described as an IP marker in healthy dogs, laboratory rats, and humans. The purpose of this study was to assess IP in dogs with CE. Thirty dogs were selected for this study: 15 healthy controls and 15 dogs with CE. Among the 15 dogs with CE, 5 had been classified as having food‐responsive enteropathy (FRE), 4 with antibiotic‐responsive enteropathy (ARE), and 6 with steroid‐responsive enteropathy (SRE). Dogs were fasted for 12 hours before oral administration 2.0 ml/kg of Omnipaque‐350 (GE Healthcare). Blood samples were collected from the jugular vein 2 hours after iohexol administration, centrifuged, and frozen. An enzyme‐linked immunosorbent assay (FIT‐GRF™ Iohexol kit, BioPAL) was used to quantify iohexol in serum. Post‐administration serum iohexol concentration were significantly higher in dogs with CE (median: 0.084 μg/mL range: 0.05–0.303 μg/mL) compared to healthy control dogs (median: 0.07 μg/mL range: 0.052–0.118 μg/mL; p = 0.042). Dogs with SRE had significantly higher post‐administration iohexol concentrations (median: 0.122 μg/mL range: 0.069–0.303 μg/mL) when compared to healthy control dogs (p = 0.013). Similarly to what has been shown in humans, this study suggests that a subset of dogs with CE have increased IP when compared to healthy dogs. This finding reinforces the need for further studies to clarify the role of IP on the pathogenesis of gastrointestinal diseases. ABSTRACT GI25 Effects of clinical characteristics and lifestyle factors on fecal canine S100/calgranulin concentrations Romy M. Heilmann 1; Melissa Guard2; Linda Toresson3; Stefan Unterer4; Aurelien Grellet5; Niels Gruetzner6; Jan Suchodolski2; Joerg Steiner2 1College of Veterinary Medicine, University of Leipzig; 2College of Veterinary Medicine and Biomedical Sciences, Texas A&M University; 3Evidensia Specialist Animal Hospital; 4Faculty of Veterinary Medicine, Ludwig‐Maximilians‐University; 5Université de Toulouse, ENVT; 6University of Veterinary Medicine Fecal S100/calgranulin (S100A12 and calprotectin) concentrations are useful markers of gastrointestinal inflammation in dogs, and the expression of S100A12 relative to that of calprotectin (fCalR) could be useful to further characterize intestinal diseases. In people, fecal S100/calgranulin concentrations are affected by age, obesity, diet, and other lifestyle factors. Knowledge about the effects of such factors on fecal S100/calgranulin concentrations in dogs is currently lacking. However, this knowledge is an important prerequisite for further clinical validation of these two biomarkers. The aim of the study was to evaluate the effect of several patient clinical characteristics and lifestyle factors on fecal S100/calgranulin concentrations and fCalR in a large cohort of healthy dogs. Single spot fecal samples from 181 healthy pet dogs and data derived from a standard questionnaire served to evaluate the effect of age, sex, reproductive status, body weight and body condition, breed type and size, vaccination, endoparasite treatment, diet, environment, and travel history on fecal S100/calgranulin concentrations and the fCalR using a multi‐variate mixed effects statistical model and by calculating the effect sizes (ES), with statistical significance set at p < 0.05. Univariate analysis showed a significant association of intact reproductive status (particularly in female dogs) with higher fecal S100A12 but lower fecal calprotectin and fCalR, and of small breed size with higher fecal S100A12 and calprotectin concentrations but lower fCalR. Pure‐bred type was linked to higher fecal S100A12 and lower fCalR, and recent vaccination (particularly with a canine parvoviral vaccine) to higher fecal S100A12 concentrations. Trends for associations were seen: diet with fecal S100A12 and calprotectin, and recent vaccination with fCalR. In multivariate models, small breed size was linked to higher fecal S100A12 and calprotectin (both of crucial clinical relevance), whereas recent vaccination affected only S100A12 concentrations (clinically moderately important increase based on ES); but no effect remained significant for fCalR. Some clinical characteristics (i.e., breed size, recent vaccination, and reproductive status in female dogs) can affect fecal S100/calgranulin concentrations, and these biomarkers should be interpreted in light of those confounding factors. The utility of population‐based reference intervals for fecal canine S100/calgranulin concentrations might be improved through stratification by sex/reproductive status and breed size. Fecal canine S100/calgranulin concentrations are not confounded by age, body condition, deworming, diet, environment, or travel history. This study provides an important basis for further evaluating the clinical utility of fecal S100/calgranulin concentrations as gastrointestinal disease markers in dogs. ABSTRACT GI26 Association of hypercobalaminemia with pathological findings in dogs and cats Romy M. Heilmann 1; Lea Sielski1; Stefanie Kather1; Franziska Dengler1; Anika Jirasek2 1College of Veterinary Medicine, University of Leipzig; 2Idexx Laboratories Germany Hypocobalaminemia is common in dogs and cats with exocrine pancreatic insufficiency and chronic enteropathies and also has prognostic value. Hypocobalaminemia has been extensively studied, but increased serum cobalamin concentrations are mostly attributed to oversupply (supplementation) and have thus received little attention in small animal medicine. Current research in human medicine associates hypercobalaminemia with severe systemic illnesses, e.g. neoplastic, hepatic, and renal diseases. Hypercobalaminemia (without prior supplementation) in cats might also be linked to solid neoplasms and hepatopathies. The aim of this retrospective study was to determine the prevalence of hypercobalaminemia and its association with pathological findings in dogs and cats. Medical records were evaluated of all dogs and cats that presented to the UL‐VMTH between 2007–2019 and had serum cobalamin concentration measured. Repeated measurements from the same patient, patients that had received supplemental cobalamin, and patients with incomplete medical records were excluded from further analyses. The proportions of patients with hypercobalaminemia (serum cobalamin concentration > 908 ng/L in dogs and > 1,334 ng/L in cats) was calculated, and the association of hypercobalaminemia with patient characteristics and pathological findings (diagnosis, affected organ system) was evaluated by χ2 test. Statistical significance was set at p < 0.05. Of the 654 dogs included in the analysis, 3% (n = 21) were hypercobalaminemic (serum cobalamin concentration 914–3,561 ng/L, median: 1,307 ng/L), 29% (n = 189) were hypocobalaminemic (<251 ng/L), and 68% (n = 441) had a serum cobalamin concentration within the reference interval (251–908 ng/L). Ten (48%) of the hypercobalaminemic dogs had chronic gastrointestinal signs, associated with an inflammatory cause (hepatopathy, enteropathy, and/or pancreatitis) or food intolerance, and 2 hypercobalaminemic dogs (10%) were diagnosed with hypoadrenocorticism. Adrenal pathology was significantly associated with hypercobalaminemia (p = 0.014). No breed predisposition existed for hypercobalaminemia, but small breeds were overrepresented (57%). Of the 315 cats included in the analysis, 11% (n = 34) were hypercobalaminemic (serum cobalamin concentration 1,370–3,107 ng/L, median: 1,713 ng/L), 29% (n = 92) were hypocobalaminemic (<270 ng/L), and 189 (60%) were normocobalaminemic (270–1,334 ng/L). Of the hypercobalaminemic cats, 65% (n = 22) had a chronic enteropathy, 24% (n = 8) acute/chronic pancreatitis, and 18% (n = 6) a cholangiohepatopathy. Neoplasia was diagnosed in 2 hypercobalaminemic cats (6%), and 1 cat was hyperthyroid. Hypercobalaminemia was not associated with a specific diagnosis or affected organ system in cats. This study suggests that hypercobalaminemia (without prior supplementation) occurs infrequently in cats, and less often in dogs. Our results confirm the prevalence of hypercobalaminemia in cats reported from a previous study. Hypercobalaminemia in dogs and cats appears to be linked to severe inflammatory, immune‐mediated, and neoplastic conditions. Whether hypercobalaminemia in dogs and cats is a benign finding and reflects an increased cobalamin‐binding capacity (transcobalamin II) or the presence of autoantibodies against transcobalamin interfering with cobalamin binding in serum warrants further study. ABSTRACT GI27 1,2‐o‐Dilauryl‐rac‐glycero‐3‐glutaric acid‐(6′‐methylresorufin) ester (DGGR) lipase assay is not specific for feline and canine pancreatic lipase Sue Yee Lim 1; Panagiotis Xenoulis2; Evangelia Stavroulaki2; Jonathan Lidbury1; Jan Suchodolski1; Frédéric Carrière3; Jörg Steiner1 1Texas A&M University; 2University of Thessaly; 3Aix‐Marseille University Measurement of pancreatic lipase is important for the diagnosis of feline and canine pancreatitis. Recent studies have claimed that lipase assays using 1,2‐o‐dilauryl‐rac‐glycero‐3‐glutaric acid‐(6′‐methylresorufin) ester (DGGR) as substrate are more specific for measuring pancreatic lipase than traditional lipase assays. However, the specificity of this assay for pancreatic lipase has not been demonstrated. Intravenous heparin administration releases hepatic and lipoprotein lipases into the bloodstream. This study aims to evaluate post‐heparin plasma lipase activity using a DGGR‐based assay and pancreatic lipase immunoreactivity (PLI) concentration in cats and dogs. We hypothesize that hepatic and lipoprotein lipases released after heparin administration can hydrolyze DGGR and contribute to plasma lipase activity measured with a DGGR‐based assay. Heparin was administered to six cats and six dogs. Blood was collected at baseline and at 10, 20, 30, 60, and 120 minutes after heparin administration. Lipase activity was measured using a DGGR‐based assay, and PLI concentration was measured by Spec fPL (for cats) or cPL (for dogs). Plasma lipase activity as measured by the DGGR‐based assay increased significantly 10 minutes after heparin administration in both cats (p = 0.003) and dogs (p = 0.006) and returned to baseline by 120 minutes. In contrast, PLI concentrations showed no significant changes after heparin administration. In conclusion, DGGR is not only hydrolyzed by pancreatic lipase but also by hepatic lipase and/or lipoprotein lipase in cats and dogs. Because these extrapancreatic lipases are present naturally in cats and dogs, they may contribute to a lack of analytical specificity for the DGGR‐based assay. ABSTRACT GI28 Markers of endothelial activation and inflammation in canine parvoviral enteritis Brogan K. Atkinson 1; Sune Pretorius2; Zandri Whitehead2; Amelia Goddard2; Paolo Pazzi2 1Onderstepoort Veterinary Academic Hospital, University of Pretoria; 2University of Pretoria Canine parvovirus (CPV) is a common cause of enteritis, immune suppression, and systemic inflammation in dogs. Markers of endothelial activation, such as intercellular adhesion molecule 1 (ICAM‐1), vascular cell adhesions molecule 1 (VCAM‐1) and high mobility group box 1 protein (HMGB‐1), provide insight into the state of the endothelium during inflammation. Cytokines known to activate the endothelium in response to inflammation include tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL‐1β), and IL‐4. This study aimed to determine if blood concentrations of endothelial markers and cytokines were increased in CPV enteritis compared to healthy controls, and whether correlation existed between endothelial markers and cytokines. Thirty dogs with naturally occurring CPV enteritis and ten age‐matched healthy control dogs were included. Endothelial markers (ICAM‐1, VCAM‐1, and HMGB‐1) were performed on stored EDTA plasma and cytokines (TNFα, IL‐1β, and IL‐4) were performed on stored serum using commercially available canine‐specific ELISA kits. In dogs with CPV enteritis ICAM‐1 was significantly lower (5.9 (IQR: 4.3–8.3) compared to controls (8.0 (IQR: 6.9–10.3) p = 0.008). No significant difference was found for VCAM‐1, HMGB‐1, and IL‐1β. TNFα and IL‐4 were below detection limit in all samples. A strong correlation between HMGB‐1 and IL‐1β (r: 0.501, p = 0.005) was identified. Despite evidence of systemic inflammation in this condition, our results suggest lack of endothelial activation and specific cytokine production based on blood concentrations. Endothelial activation, leukocyte adhesion, and subsequent transmigration through the epithelial is likely to be affected in CPV. The significance of these findings requires further investigation. ABSTRACT GI29 The impact of sampling method on gut microbial community profiles in dogs and cats Stacie Summers 1; Allysa Galloni2; Craig Webb2 1Oregon State University; 2Colorado State University Feces, rectal swabs, and colonic mucosal biopsies can be used to characterize the microbial community profiles of the descending colon using 16S ribosomal RNA (16S rRNA) gene sequencing. To date, there are no studies comparing the potential bacterial variation between these three sampling methods in dogs and cats. The aim of this study was to compare the microbial communities between feces, rectal swabs, and colonic biopsies in healthy cats and dogs as well as cats and dogs diagnosed with a chronic enteropathy (CE). Three sample types (feces, rectal swab, and endoscopic distal colonic mucosal biopsies) were collected from clinically healthy dogs (n = 9), dogs with CE (n = 8), and cats with CE (n = 7). A rectal swab and feces were collected from clinically healthy cats (n = 8). The 16S rRNA V4 region was amplified and sequenced (Illumina) for all samples using primers 515F‐806R. Sequences were processed and analyzed using Quantitative Insights Into Microbial Ecology (QIIME) v1.7.0. A Friedman test with Dunn's post hoc analysis or Wilcoxon matched‐pairs signed rank test was used to determine differences in alpha diversity indices among feces, rectal swabs, and when available, colonic biopsies for the 4 study groups. Differences in microbial community profiles between the 3 sample types were evaluated within each study group using Analysis of Similarities (ANOSIM) with Bray‐Curtis dissimilarity matrix. Chao1 was significantly higher in colonic biopsies when compared to feces in healthy dogs (p = 0.029), dogs with CE (p = 0.037), and cats with CE (p = 0.049), however, no differences were found when colonic biopsies were compared to rectal swabs. Several notable findings were found with ANOSIM. For healthy dogs, the microbial communities were not significantly different among the three sampling methods. For healthy cats, the fecal microbial community was significantly different when compared to rectal swabs (R = 0.815; p = 0.001). For dogs with CE, the fecal microbial community was significantly different when compared to the colonic biopsy samples (R = 0.251; p = 0.022). For cats with CE, the fecal microbial community was significantly different when compared to rectal swabs (R = 0.272; p = 0.001) and colonic biopsy samples (R = 0.192; p = 0.020). In conclusion, the mucosa of the distal colon exhibits higher bacterial richness compared to feces. Rectal swabs may be an alternate option to collection of fecal samples in dogs and to collection of colonic biopsies in both dogs and cats. ABSTRACT GI30 Spontaneous gastroduodenal perforations in five cats Fernanda Vieira Amorim da Costa; Izadora Zardo; Bárbara Rivas; Gabriela Schaefer; Luciana Sonne; Saulo Pavarini; Marcele Bandinelli Universidade Federal do Rio Grande do Sul Gastroduodenal perforations can be classified as spontaneous when there is a perforation with no history of recent gastrotomy and/or anastomosis, external or iatrogenic gastric trauma, gastrointestinal foreign body or volvulo‐gastric dilation. Spontaneous gastroduodenal perforations (SGP) are normally associated with pre‐existing gastroduodenal ulcers or neoplasia. In cats, SGP has been uncommonly reported in the literature. The aim of this study is to describe cases of PGE in cats seen at UFRGS's Feline Medicine Service between March 2018 and November 2019, and its possible etiologies. Five adult cats were included, four of them were mixed breed and one was Persian, three females and two males, one of them was not neutered. All patients had a history of recent surgical procedure, with an average of eight days post‐surgical time until the diagnosis of GP was made. The surgical procedures included: osteosynthesis of the mandible and tibia, hemilaminectomy, enucleation, and ovariosalpingohisterectomy. These patients were submitted to a similar anesthetic protocol, using methadone as a pre‐anesthetic medication (mean of 0.3 mg/kg), and for anesthetic induction, propofol to the effect. Surgical maintenance was performed with isoflurane and fentanyl bolus when necessary. Intraoperative hypotension was related in one cat. Four patients received anti‐inflammatory drugs, meloxicam was prescribed for three patients, at doses between 0.05 mg/kg to 0.1 mg/kg, for a maximum of 4 days, and one of them received a single dose of dexamethasone (0.25 mg/kg). Clinical presentation for SGP was diverse. Some patients had typical signs of gastrointestinal tract (vomiting, abdominal distension, and diarrhea), but most clinical signs were non‐specific, including dehydration, prostration, pale mucous membranes, anorexia or hyporexia, weight loss, hypothermia, tachycardia, hypotension, tachypnea, and hyperthermia. On hematological analysis, 80% of the cats had anemia, leukocytosis, and neutrophilia. Left deviation, lymphopenia, and monocytosis were also observed, but, metamyelocytes, myelocytes, neutropenia, and leukopenia were present in only one patient. The most common finding on blood biochemistry was hypoalbulminemia, presented in four cats. Abdominal ultrasound was performed in one patient, that showed hyperechoic mesenteric fat, gastric wall thickening (0.46 cm), presence of free echogenic peritoneal fluid and reduced motility. Diagnosis was confirmed by exploratory surgery in three cats and necropsy in two. Gastric perforations in the pyloric antrum were more common (4/5), with just one perforation in the proximal duodenum. Three patients underwent necropsy, including one that died after exploratory surgery, and histopathological examination showed transmural necrosis at the perforation site. All cats had diffuse peritonitis and the necropsy findings did not show any predisposing lesion for the injury. Gastric perforation represents a medical emergency and the condition is particularly difficult to diagnose accurately. In our study, the mortality rate for cats was 80%. Although several etiologies for SGP have been suspected, it was not possible to identify the exact origin of the perforation as in the cases mentioned in this study. GP secondary to NSAID or corticosteroid treatment has already been described in cats, and the administration of these drugs may have masked clinical signs associated with acute peritonitis. A history of recent surgery and SGP have only been associated four times in the literature, it is believed that hemodynamic and pharmacological alterations promoted by surgery and anesthesia can lead to mucosal hypoperfusion and consequent predisposing the lesion. Our records showed that SGP arising from surgical procedures are not uncommon as shown in the literature. ABSTRACT GI31 Fecal microbiome and metabolomic changes in dogs receiving antibiotics followed by placebo or synbiotics Jacqueline C. Whittemore 1; Tamberlyn Moyers2; Joshua Price1; Jan Suchodolski3 1University of Tennessee, Knoxville; 2College of Veterinary Medicine, University of Tennessee; 3Texas A&M Antibiotic‐associated gastrointestinal signs occur in ≤100% of dogs administered enrofloxacin with metronidazole; signs partially are mitigated by synbiotics. The objective of this study was to compare the fecal microbiome and metabolome of 24 healthy dogs administered enrofloxacin (10 mg/kg qd) and metronidazole (12.5 mg/kg BID), followed 1 hour later by placebo or synbiotics (Proviable®‐Forte with Proviable®‐SB), for 21 days with reevaluation 8 weeks thereafter. Fecal samples were collected on days 5–7 (baseline), 26–28, and 82–84. Sequencing of 16S rRNA genes for operational taxonomic units (OTUs) was performed and mass spectrometry used to determine metabolomic profiles. p < 0.05 was considered significant, with Benjamini & Hochberg's False Discovery Rate used to adjust for multiple comparisons. Alpha and beta diversity differed significantly from baseline during treatment and on days 82–84. At the genus level, significant group‐by‐time interactions were noted for 15 OTUs, including Adlercreutzia, Bifidobacterium, Slackia, Turicibacter, Clostridium, [Ruminococcus], Erysipelotrichaceae_g_, [Eubacterium], and Succinivibrionaceae_g_. Group and time effects were present for an additional 6 OTUs, including Collinsella, Ruminococcaceae_g_, and Prevotella. Metabolite profiles differed significantly by group‐by‐time, group, and time for 28, 20, and 192 metabolites, respectively. Short‐chain fatty acid, bile acid, indole, sphingolipid, polyamine, and cinnaminic acid metabolites were affected, with some changes persisting through days 82–84 and differing between groups. Antibiotic administration causes sustained dysbiosis in dogs with similar changes in the microbiome and metabolome to those found in cats. Significant group‐by‐time interactions were noted for a number of OTUs and metabolites, potentially contributing to decreased antibiotic‐induced gastrointestinal effects in dogs administered synbiotics. ABSTRACT GI32 Concurrent gastrointestinal signs in hypothyroid dogs Eleonora Gori2; Giada Paolinelli2; Paola Gianella3; Alessio Pierini2; George Lubas 1; Veronica Marchetti2 1Deptartment of Veterinary Sciences, University of Pisa; 2University of Pisa; 3University of Turin [Correction added on November 9, 2020 after first online publication: ABSTRACT GI32 Concurrent gastrointestinal signs in hypothyroid dogs has incorrect author order. The correct order is Eleonora Gori2; Giada Paolinelli2; Paola Gianella3; Alessio Pierini2; George Lubas 1; Veronica Marchetti2. The presenter is still George Lubas.]   Few observations about prevalence and features of gastrointestinal (GI) signs in hypothyroid dogs (hypoT‐dogs) are available. The study aimed (1) to evaluate concurrent GI signs in hypoT‐dogs; (2) to analyze clinico‐pathological and ultrasound features of hypoT‐dogs with and w/out GI signs, and (3) to analyzed GI signs follow‐up after thyroid hormone replacement therapy (THRT). Medical records of hypoT‐dogs from two Veterinary Teaching Hospitals were retrospectively reviewed. Dogs were classified as hypothyroid if TT4 or fT4 were low/normal with normal/high TSH or inadequate TSH‐stimulation test response. Clinical history, GI signs (vomiting, diarrhea, constipation), hematobiochemical parameters and abdominal ultrasound were collected. HypoT‐dogs were divided based on the presence of at least one GI signs (GI group and not‐GI group). Twenty‐seven GI dogs had 3–4 weeks recheck from the beginning of THRT and information on GI signs were recorded. A total of 166 dogs were included (GI group, n = 45, 27%; not‐GI group, n = 121, 73%). GI dogs showed nausea (42%), vomiting (40%), constipation (22%), large bowel diarrhea (40%), small bowel diarrhea (4%), and aspecific diarrhea (40%). No significant difference between GI and not‐GI groups on hematobiochemical parameters was found. GI group had significantly higher frequency (20%) of large intestine involvement than not‐GI group at the ultrasound (p = 0.03; Chi‐square test). Twenty‐one out of 27 GI dogs had a resolution of GI signs at recheck (p = 0.0001; McNemar test). Most of hypoT‐dogs had concurrent GI signs mainly due to large bowel involvement. After THRT beginning the concurrent GI signs in hypoT‐dogs seem to be reduced. ABSTRACT GI33 Feasibility and complications of video capsule endoscopy in 38 dogs with suspected gastrointestinal bleeding Jenny Stiller 1; Alice Defarges2; Brigitte Brisson2; Alexa Bersenas2; David Pearl2 1Ontario Veterinary College, University of Guelph; 2University of Guelph This study aimed to assess feasibility and complications of video capsule endoscopy (VCE) in dogs with occult or overt gastrointestinal bleeding (GIB). From August 2017 to November 2019, a total of 38 dogs (23.1 kg ± 11.2) were examined by VCE because of suspected occult (26) and overt (12) GIB. The ALICAM® was administered orally (28) or by endoscopic deployment (10) after 12 hours of fast. Preparation included enemas (29), administration of polyethylene glycol (19). A standard scoring system was used for GI visibility. All ALICAM® were administered uneventfully and excreted spontaneously. Median transit time of the capsule from administration to excretion was 30.5 hours (range 2.5 hours‐8 days). Complications included incomplete studies due to temporary gastric retention (14), lost VCE (1), and unrelated sudden death (1), or euthanasia (1). GI visibility was good to excellent in the stomach and small intestine, limited to poor in the colon. Bleeding lesions were identified in 22 dogs (10 with overt GIB, 12 with occult GIB), and included gastric ulcerations (13 dogs), intestinal ulcerations (6 dogs) and gastric/intestinal/colonic vascular ectasia (2 dogs); intestinal lymphangiectasia was identified on ALICAM® in 2 dogs subsequently confirmed by endoscopic biopsies. In 2 dogs with overt GIB, a bleeding lesion was not identified. VCE is a safe procedure and can be used to diagnose a variety of bleeding lesions in the GI tract of dogs. In ALICAM delivered per os, prolonged gastric retention leading to incomplete studies was frequently noted. Further studies are needed to improve study completion. ABSTRACT GI34 Use of a synbiotic for treating antibiotic‐induced diarrhea in cats Jeremy A. Kiene 1; Kelsey Dobesh1; Michael Lappin2 1Center for Companion Animal Studies, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University; 2College of Veterinary Medicine and Biomedical Sciences, Colorado State University Diarrhea is a common and potentially significant complication in cats undergoing antibiotic therapy. Data supporting the benefit of supplementing probiotics or synbiotics to cats when antibiotic‐induced diarrhea has started is lacking. This study examines effects of supplementing a synbiotic (Enterococcus faecium SF68 and psyllium) to cats with pre‐existing antibiotic associated diarrhea. Sixteen healthy, young‐adult research colony cats fed a commercial dry food were administered amoxicillin‐clavulanate (Clavamox) at 62.5 mg/cat twice daily. Using a standardized fecal scoring system, trained, masked personnel scored feces every twelve hours, with scores >4 considered diarrhea. Clavamox was discontinued if fecal scores were > 4 for 2 days. Cats were then randomized into 2 treatment groups, one supplemented with the synbiotic in 15 g of canned food once daily, the other supplemented with the palatability enhancer from the synbiotic in 15 g of canned food once daily. Diarrhea was less severe overall in the synbiotic group, with 24.5% of fecal samples scored >5, compared with 48.9% in the control group (p = 0.0132). Time to diarrhea resolution was 4.5 periods from initiation of treatment in the synbiotic group, compared with 6.5 periods in the control group (p = 0.472). Clinical resolution of diarrhea was achieved in all cats in the synbiotic group. Two cats in the control group had a rescue protocol instituted for diarrhea that failed to resolve during the study period. These results indicate that supplementing this synbiotic to cats with diarrhea provoked by administration of Clavamox reduces severity of diarrhea and may decrease time to resolution. ABSTRACT GI35 Comparing adipose‐derived mesenchymal stem cells to prednisolone for the treatment of feline inflammatory bowel disease Craig B. Webb 1; Tracy Webb2 1Veterinary Teaching Hospital, Colorado State University; 2Colorado State University A 2015 proof‐of‐concept study confirmed the safety and potential benefit of treating feline chronic enteropathy with adipose‐derived mesenchymal stem cells (fMSC). As a follow‐up, this study was designed to compare the efficacy of fMSC to standard prednisolone therapy in confirmed inflammatory bowel disease (IBD). Cats were screened for significant concurrent diseases (history, PE, fecal, CBC, chemistry, urinalysis, TT4, TX A&M GI panel) and food‐responsive diarrhea (2‐week diet trial). IBD was confirmed by multi‐site histopathology, IHC, PARR, and flow cytometry. Enrolled cats were randomly assigned to the fMSC or prednisolone group. All cats received appropriate placebo (IV saline injection or oral liquid vehicle), and owners were blinded to the grouping. fMSC treatment consisted of 2 injections (2 x 106 cells/kg) of allogeneic, fMSC from a single specific pathogen free donor separated by 2‐weeks. Prednisolone treatment consisted of 1–2 mg/kg per os daily, tapered according to clinical response. Owners were asked to make no other changes for the first 2‐months at which time they either continued with no changes to the 6‐month recheck (cat stable/owner satisfied) or “failed,” were unblinded, and changes made as necessary (cat not doing well/owner seeking alternate therapy). Six prednisolone and 6 fMSC cats completed the study. All 6 prednisolone cats were female‐spayed, mean age 8.3 yrs (range 2–14), mean body weight (BW) 3.6 kg (range 2.5–4.8), and mean pre‐treatment FCEAI score 3.4 (range 1–6). The 6 fMSC cats included 3 female‐spayed and 3 male‐castrated, mean age 8 yrs (range 4.5–13), mean BW 4.9 kg (range 4–5.9), and mean pre‐treatment FCEAI score 3.7 (range 2–5). One cat in each group failed at the 2‐month recheck. For the remaining cats, at the 6‐month recheck, the mean FCEAI score for the prednisolone group was 3.7 (range 0.5–9) and 1.0 (range 0–1.5) for the fMSC group. These results suggest that this fMSC protocol is as effective in the treatment of feline IBD as a standard course of prednisolone. ABSTRACT GI36 Antibiotic administration results in long‐term changes to the immature feline fecal microbiome Evangelia Stavroulaki 1; Jonathan Lidbury2; Joerg Steiner2; Jan Suchodolski2; Panagiotis Xenoulis3 1University of Thessaly; 2Gastrointestinal Laboratory, Texas A&M University; 3Clinic of Medicine, Faculty of Veterinary Science, University of Thessaly Antibiotic treatment (AT) during early life profoundly affects gastrointestinal (GI) microbial composition and function and delays the developmental progression of the microbiome in humans and experimental animals. In humans, it has been shown that antibiotic induced intestinal dysbiosis during infancy and childhood is associated with increased risk for several GI and non‐GI related disorders later in life. The aim of this study was to investigate the effect of AT on specific bacterial groups that are potentially associated with GI dysbiosis in kittens. Naturally passed feces were collected from 23 healthy control kittens (Group 1), and 42 kittens that received antibiotics. AT kittens were presented for evaluation and treatment of upper respiratory tract disease and were randomly assigned to receive either amoxicillin/clavulanic acid (Group 2; n = 22) for 20 days or doxycycline for 28 days (Group 3; n = 20) as part of their standard treatment. Feces were collected on days 0 (baseline), 20 or 28, respectively (last day of AT), 60, 120, and 300. Kittens were approximately 2 months of age at enrollment and received the same diet and antiparasitic treatment during the study period. Kittens were excluded if they received medications known to affect the GI microbiota prior to or during the study period, or if they had or developed significant disease that might have affected the GI microbiota. DNA was extracted from each fecal sample and qPCRs were performed for total bacteria, Turicibacter spp., Faecalibacterium spp., Streptococcus spp., Escherichia coli (E. coli), Blautia spp., Fusobacterium spp., Clostridium hiranonis (C. hiranonis), and Bifidobacterium spp. Data were assessed for normality and appropriate statistical analyses were used for independent measurements. Statistical significance was set at p < 0.05 and correction for multiple comparisons was performed where appropriate. No differences in bacterial abundances were identified among groups on day 0. On day 20, the abundance of total bacteria, Streptococcus spp., and C. hiranonis were decreased in Group 2 compared to Group 1 (p = 0.001, 0.045, and 0.005, respectively). Faecalibacterium spp., and Blautia spp. were decreased in Group 2 compared to Group 1 or Group 3 (p = 0.008, and 0.001, respectively). On day 20 E. coli was increased in Group 2 (p < 0.001) and on day 60 in Group 3 (p = 0.008) compared to Group 1. On day 120, Faecalibacterium spp. and Bifidobacterium spp. were increased in Group 2 compared to Group 1 (p = 0.019, and 0.049, respectively). On day 300, total bacteria were increased in both AT groups compared to Group 1 (Group 2: p = 0.038; Group 3: p = 0.033). In conclusion, similar to humans, both amoxicillin‐clavulanic acid and doxycycline appear to influence bacterial taxa commonly associated with dysbiosis in kittens, with changes persisting for at least 10 months after their discontinuation. ABSTRACT GI37 Coagulation status, fibrinolysis, and platelet dynamics in dogs with chronic inflammatory enteropathy Sara A. Wennogle 1; Christine Olver2; Sarah Shropshire2 1Colorado State University; 2Department of Clinical Sciences, Colorado State University The hypercoagulable state associated with canine chronic enteropathy is poorly understood. The objective of this study was to utilize thromboelastography (TEG) to assess coagulation status and fibrinolysis and platelet aggregometry to assess platelet function in dogs with chronic inflammatory enteropathy (CIE) compared to healthy controls (HC). Twenty‐six dogs with CIE were prospectively enrolled. Data from 14 HC was available for comparison. All dogs had tissue factor (TF) + tPA (tissue plasminogen activator) TEG performed. 10/26 CIE dogs and all HC had adenosine diphosphate (ADP) and arachidonic acid (AA) whole blood impedance platelet aggregometry performed. Standard clinical, clinicopathologic, and coagulation data were available for all dogs and correlated to TEG values. Dogs with CIE had higher maximum amplitude (MA)‐TF‐tPA (p < .001), longer clot lysis times (CLT) (p = .008), and lower LY30 (p = .002) and LY60 (p = .002) values when compared to HC, suggesting hypercoagulability and hypofibrinolysis. Although serum albumin concentrations had a weak (rho value, −.46) correlation (p = .02) with MA‐TF‐tPA, 10/16 (63%) normoproteinemic and 9/10 (90%) hypoproteinemic dogs were considered hypercoagulable based on TEG using MA >60 mm to define hypercoagulability. Serum albumin concentrations were also weakly correlated to LY30 (rho value, .44; p = .03) and LY60 (rho value, .46; p = .02). Serum 25(OH)D concentrations were moderately (rho value, −.6375) correlated (p < .001) to MA‐TF‐tPA. Plasma fibrinogen and antithrombin concentrations were moderately (rho value, .55; p = .004) and weakly (rho value, −.42; p = .03) correlated to MA‐TF‐tPA. Platelet aggregometry was not different between groups. Both normoproteinemic and hypoproteinemic dogs with CIE were considered hypercoagulable and hypofibrinolytic based on TEG when compared to HC. Humans with inflammatory bowel disease have been demonstrated to have anti‐tPA antibodies that are suspected to contribute to a hypofibrinolytic state and recently, anti‐thrombotic actions of vitamin D have been evaluated. More work is needed to determine if these factors could play a role in the coagulation status of dogs with CIE, and whether they could become targets for therapy in the future. ABSTRACT GI38 Enhanced gut microbial fermentation and metabolism by different starch‐rich products in a canine gastrointestinal model Sergi Segarra 1; Jonas Ghyselinck2; Pieter Van den Abbeele2; Massimo Marzorati3 1Bioiberica SAU; 2ProDigest BVBA; 3CMET, Faculty of Bioscience Engineering, Ghent University The purpose of the study was to evaluate the prebiotic effects of three different starch‐rich products on gut microbial activity using an in vitro canine gastrointestinal model. The simulator of the canine intestinal microbial ecosystem (SCIME) platform was used to simulate the colonic environment in a single stage reactor setup and assess the effects of three products (2201, 2202, and 2203) using a freshly prepared fecal inoculum from a healthy adult Beagle dog as a single donor. All tested products contained the same source of chondroitin sulfate, β‐glucans and mannanoligosaccharides; but a different source of starch: high amylose maize starch (2201), tapioca dextrin (2202), and tapioca maltodextrin (2203). A sugar‐depleted nutritional medium was used as negative control (blank). Products were incubated for 48 hours at 39°C, under shaking (90 rpm) and anaerobic conditions at a concentration of 5 g/L. Each condition was performed in triplicate. Changes in microbial fermentation (pH and gas production), and metabolic activity [levels of lactate, ammonium, and short‐chain fatty acids (SCFA)] were analyzed after 0, 6, 24, and 48 hours. Comparisons between groups overtime for the different parameters were performed using unpaired two‐tailed Student's T‐test. Differences were considered statistically significant if p value was <0.05. All three tested products were well fermented by the canine microbiota and led to significantly lower pH and ammonium levels, and to significantly higher production of gas and total SCFA (approximately, 2‐fold higher vs. blank). Product 2201 yielded highest lactate, acetate and butyrate concentrations and a more marked pH decrease than the other two products, while products 2202 and 2203 led to highest propionate concentrations. Fermentation of product 2201 slightly lowered branched SCFA concentrations compared to control, while products 2202 and 2203 showed slightly higher branched SCFA concentrations than the control. Product 2201 also appeared to exert a faster effect, especially during the first 6–24 hours. In conclusion, the three tested combinations of chondroitin sulfate, β‐glucans, mannanoligosaccharides and starch were well fermented by the gut microbiota of the Beagle dog and enhanced the in vitro production of health‐related metabolites, hence confirming a remarkable prebiotic effect. Moreover, the combination including maize as source of starch led to superior results. Although further investigations are warranted, these results point towards the potential clinical usefulness of such combinations in dogs with chronic enteropathies.   ABSTRACT GI39 Increased expression of the ileal cobalamin receptor in hypocobalaminemic dogs with idiopathic inflammatory bowel disease Stefanie Kather 1; Johannes Kacza2; Helga Pfannkuche3; Gotthold Gäbel3; Jörg Steiner4; Franziska Dengler3; Romy Heilmann1 1Small Animal Clinic, Veterinary Teaching Hospital, Institute of Veterinary Physiology, University of Leipzig; 2Saxon Incubator for Clinical Translation, Bioimaging Core Facility, University of Leipzig; 3Institute of Veterinary Physiology, University of Leipzig; 4Gastrointestinal Laboratory, Texas A&M University Idiopathic inflammatory bowel disease (IBD) in dogs can be associated with cobalamin deficiency. Hypocobalaminemia is also a risk factor for negative outcome in dogs with IBD, and affected dogs may not respond to treatment unless receiving supplemental cobalamin. Thus, it has been proposed that the uptake of cobalamin from the intestinal lumen is compromised as a result of ileal receptor deficiency in dogs with IBD. However, expression of the cobalamin receptor in dogs with chronic intestinal inflammation has not yet been studied. The aim of this study was to quantify the expression of the cobalamin receptor subunits amnionless (AMN) and cubilin (CUBN) in ileal biopsies from dogs with IBD in comparison to healthy dogs. Endoscopic biopsies from the canine ileum were evaluated from dogs that were assigned to one of the following study groups: (1) dogs with IBD and severe hypocobalaminemia (n = 6), (2) dogs with IBD and suboptimal serum cobalamin status (n = 7), (3) dogs with IBD and normocobalaminemia (n = 7), and (4) healthy control dogs (n = 9). Formalin‐fixed and paraffin‐embedded sections of tissue sections were stained for AMN and CUBN using polyclonal primary and fluorescence‐labeled secondary antibodies. AMN and CUBN expression was quantified using confocal laser scanning microscopy. Receptor expression was compared among the groups of dogs and was also correlated with clinical patient data (i.e., age, sex, canine chronic enteropathy clinical activity index [CCECAI] score, serum cobalamin and folate concentrations, and histopathologic criteria). Statistical significance was set at p < 0.05. Ileal mucosal expression of AMN and CUBN was significantly higher in the group of severely hypocobalaminemic dogs with IBD (median: 5.0 and 4.4, respectively) compared to healthy control dogs (median: 3.4; p = 0.007 and median: 3.4; p = 0.034, respectively). There was no significant difference among any of the other groups of dogs. AMN expression in ileal biopsies was significantly correlated with age (p = 0.001), sex (p = 0.030), CCECAI score (p = 0.036), the severity of ileal lacteal dilatation (p = 0.039), duodenal macrophage infiltration (p = 0.027), and with serum folate (p = 0.004), but not serum cobalamin concentrations (p = 0.420). CUBN expression was correlated with AMN expression (p < 0.0001), age (p = 0.020), ileal macrophage infiltration (p = 0.020), and serum folate concentration (p = 0.008), but also not serum cobalamin concentration (p = 0.399). Expression of the cobalamin receptor subunits AMN and CUBN appears to be altered in severely hypocobalaminemic dogs with IBD. Contrary to the previously proposed pathogenetic mechanism, cobalamin receptor downregulation does not appear to be the primary cause of severe hypocobalaminemia in canine IBD. Additionally, there was a relation between cobalamin receptor expression and several patient characteristics: more severe clinical signs (CCECAI score > 9), histopathologic presence of lacteal dilatation and macrophage infiltration, older age (>7 years), and male sex (regardless of neuter status) were associated with a higher AMN expression. Higher CUBN expression was associated with older age (>7 years) and presence of macrophage infiltration. The underlying mechanisms and clinical implications of these findings, and also the effect of selected patient characteristics on AMN and CUBN expression, warrant further investigation. ABSTRACT HM01 Immune profiles of cocker spaniels and old english sheepdogs, breeds predisposed to autoimmune blood disorders Michael Barchilon 1; Austin Viall1; Jordan Gagne1; Emily Phalen1; Paula Boggiatto2; Robert Schaut3; Unity Jeffery4; Marjory Brooks5; Dana LeVine1 1Iowa State University; 2National Animal Disease Center; 3Elanco Animal Health; 4Texas A&M University; 5Cornell University Cocker Spaniels (CS) and Old English Sheepdogs (OES) are predisposed to immune‐mediated hemolytic anemia (IMHA) and immune thrombocytopenia (ITP). Decreased regulatory T‐cells (Treg) in ITP and elevated macrophage/monocyte recruiting cytokines and keratinocyte chemoattractant (KC)) in canine IMHA (monocyte chemoattractant protein‐1 (MCP‐1) are described. We aimed to determine if healthy CS and OES have altered immune cell and cytokine profiles versus other breeds, hypothesizing decreased Tregs, increased MCP‐1 and increased KC. We prospectively enrolled healthy CS (21), OES (23) and age/sex‐matched dogs of other breeds (42). Circulating Tregs, CD4+ and CD8+ T‐cell percentages were determined flow cytometrically, serum cytokines assayed via multiplex, and leukograms performed. CS, OES, and matched controls were compared with paired parametric/non‐parametric tests. We found no differences in Tregs between CS (mean 5.6%, 95% CI 4.4–6.8%) and CS‐controls (5.7%, 4.6–6.8%) or between OES (median 6.0%, 4.8–7.7%) and OES‐controls (median 5.5%, 4.8–6.6%). CD4+ and 8+ percentages were similar between groups. We identified several cytokines elevated in CS versus controls: Interleukin‐7 (CS median 142.7 pg/ml, 52.8–256.6; control 72.0 pg/ml, 50.0–110.2; p = 0.035), MCP‐1 (CS median 399.3 pg/ml, 343.7–481.0; control 348.2, 318.6–379.6; p = 0.022), and KC (CS mean 683.5 pg/ml, 522.4–844.5; control 445.8, 319.6–572.0; p = 0.0005). CS had increased percent (CS mean 5.2%, 4.1–6.3; control 3.6%, 2.9–4.2; p = 0.016) and absolute (CS mean 613/μl, 448–778; control 334/μl 265–403; p = 0.0029) monocytes. Our data combined with previous canine IMHA cytokine studies suggest that CS may have a breed‐related state of monocyte/macrophage activation enhancing susceptibility to autoimmune blood disorders. ABSTRACT HM02 Comparison of direct venipuncture versus peripheral catheter samples for serum biochemistry testing in dogs Aria L. Guarino; Allison O'Kell; Andrew Specht; Sarah Beatty University of Florida Veterinary Hospitals Drawing blood from dogs for serum biochemistry (SB) analysis from a freshly placed peripheral intravenous catheter (PIVC) rather than direct venipuncture (DV) has the potential to reduce patient morbidity and improve efficiency. However, whether PIVC blood collection provides reliable SB results has not been assessed in dogs. The purpose of this study was to determine whether there is clinically acceptable agreement between SB results from samples collected from a PIVC at the time of placement and samples collected contemporaneously by DV in dogs. This was a prospective study involving 61 dogs presenting for clinical illness or elective procedures that required PIVC placement. Samples were collected by DV and through a freshly placed PIVC in randomized order and processed immediately. Bland‐Altman analysis was used to determine whether there was clinically acceptable agreement between the two sampling methods based on application of a priori limits of agreement (LoA) from previously published recommendations. Most analytes had results that were within the LoA 100% of the time. Analytes with results within the LoA 95–99% of the time (between 1–3 cases outside LoA) included alkaline phosphatase, phosphorus, glucose, and bicarbonate. The remaining analytes (aspartate aminotransferase, total bilirubin, and potassium) had results within the LoA 92%, 90%, and 83% of the time respectively. Based on this data, it appears that blood samples collected from PIVC, while not entirely equivalent to those collected by DV, generally provide results within previously published guidelines for clinically acceptable agreement. However, some values such as potassium require more cautious interpretation. ABSTRACT HM03 Evaluation of hemostasis in hyperthyroid cats Audrey Keebaugh 1; Stefanie DeMonaco1 ; David Panciera1; Jonathan Abbott2; Katie Boes1; Giulio Menciotti1 1Virginia‐Maryland College of Veterinary Medicine; 2College of Veterinary Medicine, University of Tennessee Hyperthyroid cats are predisposed to thrombus formation. The mechanism for thrombogenesis is currently unknown, but could be associated with altered hemostasis as seen in hyperthyroid humans. The purpose of this study was to evaluate markers of hemostasis in hyperthyroid cats compared to healthy cats, and in hyperthyroid cats before and after treatments with radioactive iodine (RIT). Twenty‐four cats with hyperthyroidism (elevated serum T4 concentration) and 12 healthy euthyroid cats >8 years of age were studied. Blood was collected by jugular venipuncture for measurement of prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, antithrombin (AT), and D‐dimers. An echocardiogram was performed in all cats and healthy cats with abnormal echocardiograms were excluded. A normal echocardiogram was defined as two‐dimensional (2D) and M‐mode left ventricular free wall and interventricular septal wall thickness at end‐diastole of <6 mm, 2D left atrium to aortic ratio of <1.5, no or only trivial insufficiencies of the pulmonic and tricuspid valves, and no insufficiency of the aortic and mitral valves. Measurements of hemostasis were evaluated again >6 months after RIT in 8 hyperthyroid cats. The Wilcoxon signed‐rank test was used to compare measurements of hemostasis between hyperthyroid and euthyroid controls, pre and post RIT values, and in hyperthyroid cats with normal versus abnormal echocardiograms. Linear regression analysis was used to test for correlation of serum T4 and fibrinogen and serum T4 and antithrombin. The median serum T4 was 134 nmol/L (range 49–509 nmol/L [reference interval 16–37.7 nmol/L]) in hyperthyroid cats. Median follow up serum T4 was 23.3 nmol/L (range 16.3–48.9 nmol/L). Fibrinogen and AT were significantly greater (p < 0.001) in hyperthyroid cats compared to healthy controls. After RIT, there was a significant decrease in fibrinogen and antithrombin (p < 0.01 and p = 0.02, respectively) and a significant prolongation of PT (p = 0.03). Fibrinogen and antithrombin had a strong positive correlation with serum T4 value (r = 0.79; 95% CI 0.62–0.89 and r = 0.71; 95% CI 0.49–0.84, respectively). Significant differences were not detected when hemostatic markers from hyperthyroid cats with normal or abnormal echocardiograms were compared. These results provide evidence of altered hemostasis in hyperthyroid cats that is independent of cardiac abnormalities. These differences resolved after radioiodine therapy. ABSTRACT HM04 Effect of duration of canine blood storage on red blood cell alloimmunization and compatibility testing Alison Thomas‐Hollands ; Rebecka Hess; Nicole Weinstein; Kimberly Marryott; Samantha Fromm; Nicole Chappini; Mary Beth Callan University of Pennsylvania Longer duration of RBC storage has been associated with increased RBC alloimmunization in a mouse transfusion model, as well as development of spurious major crossmatch incompatibilities with equine blood. The objectives of this prospective study were: 1) to determine if longer duration of storage of canine pRBCs is associated with increased RBC alloantibody formation in transfused dogs, and 2) and if storage duration has an effect on compatibility testing. Transfusion‐naïve dogs in need of a RBC transfusion were included. Pre‐ and post‐transfusion plasma/serum samples were stored at −80°C until fresh RBCs from the original blood donor were available. Major crossmatches were performed using standard gel columns, with and without addition of canine antiglobulin reagent. Whole blood segments from pRBC units were used for major and minor crossmatches (gel column) after storage for 0, 7, 14, 21, 28, and 35 days. Pre‐ and post‐transfusion samples were available for 27 dogs that received a median of 1 pRBC transfusion (range, 1–4). Post‐samples were obtained a median of 24 days (range, 6–388) after the first pRBC transfusion. Eleven of 27 (41%) dogs developed major crossmatch incompatibilities, but 5 of 27 (19%) dogs had detectable RBC alloantibodies only with the addition of antiglobulin. Transfused pRBC units had been stored a median of 24 days (range, 1–32). There was no association between duration of pRBC storage and development of major crossmatch incompatibilities. Serial major (n = 66) and minor (n = 69) crossmatches were performed weekly with pRBC units (n = 24) stored for 35 days. There were no significant changes in compatibility over time. In conclusion, RBC alloantibody formation is common in dogs post‐transfusion but not associated with longer duration of pRBC storage. Unlike equine blood, storage of canine pRBC units for 35 days does not result in spurious changes in crossmatch compatibility over time. ABSTRACT HM05 Cryopreserved platelets versus lyophilized platelets for management of thrombocytopenia associated bleeding in dog Robert Goggs 1; Benjamin Brainard2; Janine Calabro3; Karyn Harrell4; Philip Bergman5; Tracy Mills5; Dana LeVine6; Richard Stone7; Benjamin Davidson7; Christine Iacovetta7; Lauren Harris7; John Gicking7; Brenda Fulcher8; Teresa Lightfoot8; Meredith Miller9; John Loftus9; Jennifer Kishbaugh10; Anne Hale10 1Cornell University; 2University of Georgia; 3Friendship Veterinary Hospital; 4North Carolina State University; 5VCA Clinical Research, VCA Animal Hospitals; 6Iowa State University; 7Blue Pearl Pet Hospital; 9Blue Pearl Science; 10Cornell University College of Veterinary Medicine; 11BodeVet Inc. Lyophilized platelet products have long shelf‐lives and can be easily transported, stored, and administered in various settings. Thrombocytopenia is common in canine critical care, but limited availability of fresh platelet concentrates in veterinary medicine necessitates more frequent use of DMSO‐stabilized cryopreserved canine platelets. A novel trehalose‐stabilized lyophilized canine platelet product was recently developed, but its efficacy in dogs with clinical bleeding is unknown. This multicenter, randomized, non‐inferiority clinical trial compared DMSO‐stabilized cryopreserved canine platelets (CP) with a trehalose‐stabilized lyophilized canine platelet product (LP) for the control of life‐threatening thrombocytopenic bleeding in dogs. Dogs with platelet counts <50 × 109/L and evidence of active bleeding using a standardized bleeding assessment tool (DOGiBAT) were randomized to receive 3 × 109 platelets/kg of LP or CP. Primary outcome measures were DOGiBAT score, platelet count, need for additional red cell transfusion and all‐cause mortality. In total, 91 dogs were enrolled; 53 received LP and 38 received CP. Baseline demographics and clinical characteristics of both groups were comparable. At 1‐hour post‐transfusion the LP were superior for the change in DOGiBAT score, and non‐inferior at 24‐hours post‐transfusion. The LP were non‐inferior to the CP for change in platelet count, need for additional red blood cell units and for survival to discharge. LP were superior for change in hematocrit at 1‐hour post‐transfusion, and non‐inferior at 24‐hours. No adverse effects were noted in either group. In conclusion, a novel lyophilized canine platelet product is non‐inferior to DMSO‐stabilized cryopreserved platelets for management of thrombocytopenic bleeding in dogs. ABSTRACT HM06 Inhibition of myristoylated alanine‐rich c kinase substrate (MARCKS) decreases canine clot retraction and platelet aggregation Allison J. Rowland; Samuel Jones North Carolina State University Thrombosis in canines is a recognized consequence of many disease processes and some treatments and is associated with increased morbidity and mortality. Use of antithrombotic therapy is increasing though treatment options are limited, require frequent monitoring, and may cause unwanted bleeding. A better understanding of canine platelet function may elucidate new methods of treatment. Myristoylated alanine‐rich C kinase substrate (MARCKS) protein helps to regulate cellular events utilizing dynamic actin reorganization and is essential for platelet function. This study was performed to determine the role of MARCKS in canine platelet function. Blood was collected from healthy dogs for whole blood clot retraction (n = 4), optical platelet aggregometry using platelet rich plasma (n = 6), or isolated platelet adhesion assay using a luminescence assay (n = 7). A MARCKS‐specific inhibitor peptide called myristoylated n‐terminal sequence (MANS) was used to block MARCKS function and the negative control peptide was random n‐terminal sequence (RNS) which has a rearranged form of the same 24 amino acids as MANS. Each assay was performed on samples exposed to phosphate‐buffered saline (unexposed control), RNS (negative control), and MANS (treatment). Gross visual change in clot size was recorded for the whole blood clot retraction assay. Results of aggregometry and adhesion assays were analyzed using a one‐way ANOVA with Tukey's multiple comparisons test. All whole blood clot retraction samples had decreased clot retraction in the MANS treated group compared with the unexposed and negative controls. For the optical platelet aggregometry there was a significant decrease in the percent aggregation in the MANS treated group as compared with the unexposed and negative controls (p = 0.023 and p = 0.0073, respectively). Results of the platelet adhesion assay showed a significantly decreased adhesion in the MANS treated group as compared with the unexposed control group (p = 0.036) though no significant difference between the MANS and RNS groups (p = 0.566) was found. These results support that MARCKS protein is essential in canine clot retraction and platelet aggregation. Inhibiting MARCKS is a potential therapeutic target for the treatment of thrombosis in canines. ABSTRACT HM07 Neutropenia in dogs receiving vincristine for treatment of immune‐mediated thrombocytopenia Kathryn LaQuaglia ; James Robertson; Katharine Lunn College of Veterinary Medicine, North Carolina State University Myelosuppression, specifically neutropenia, is a recognized adverse effect of vincristine when used in multidrug chemotherapy protocols. The incidence of neutropenia, or other indicators of myelosuppression, in dogs receiving vincristine for treatment of immune‐mediated thrombocytopenia (ITP) has not been reported. A retrospective cohort study was performed to determine the incidence of neutropenia, and evaluate risk factors, in dogs receiving vincristine for treatment of ITP. Client‐owned dogs with severe thrombocytopenia (platelet count ≤15,000/μL), presumptively diagnosed with ITP, over a 15‐year period were included. Cases were excluded if they were diagnosed with neoplasia, presented with neutropenia, or were treated with vincristine prior to admission. Administration of immunomodulatory agent(s) or human intravenous immunoglobulin, vincristine dose, presence of hyperbilirubinemia, and vector‐borne disease status were evaluated as potential risk factors, using logistic regression models. 143 dogs were included in the study, of which 126 received vincristine; 19 of them became neutropenic. Neutropenia was identified between 2 and 14 days (median 5 days) after vincristine administration, and resolved between 1 and 8 days (median 3 days) following nadir. Furthermore, of 36 dogs with ITP with an initial regenerative anemia, 28 received vincristine, and the anemia became non‐regenerative in 23 of these dogs. Of the risk factors evaluated, cyclosporine administration was significantly associated with development of neutropenia in dogs receiving vincristine (p = 0.00001). These results suggest that alternative immunomodulatory agents, delay in the initiation of cyclosporine treatment, or vincristine dose reductions for dogs chronically receiving cyclosporine should be considered when using vincristine for treatment of ITP. ABSTRACT HM08 Evaluation of hematocrit in juvenile shelter dogs presenting for routine ovariohysterectomy or neuter Kate KuKanich ; Joshuah Klutzke; Nora Springer; Butch KuKanich Kansas State University Hematological parameters are established for healthy juvenile dogs. Applicability of these reference values to a shelter population of dogs with potential comorbidities is unknown. Shelter dogs (77 female, 61 male) of varied breeds presented to the Kansas State University Junior Surgery Laboratory. All dogs received physical examinations including dental aging, CBC, 4Dx, and flea comb, and dogs with diarrhea had fecal float +/− parvovirus test. Dogs were grouped into 3 categories: Puppies (P) with no adult incisors (<3 months old); Mideruption (M) with some adult incisors (3–6 months old); or Adult (A) with all adult canines (>6 months old). A one‐way ANOVA was used to compare hematocrit (HCT) between groups. There were 34 P, 22 M, and 82 A dogs, with mean calculated HCT 35.6% (range 27–46), 37% (31–48%), 45.8% (34–59%), respectively. Nine dogs had positive 4Dx results [3 Anaplasma (HCT 36–56%), 5 Ehrlichia (HCT 34–47%), 1 heartworm (HCT 50%)]. Twelve dogs had fleas or flea dirt [10 A (HCT 37–47%), 1 M (HCT 37%), and 1 P (HCT 30%)]. Two dogs had hookworms (HCT 29–35%), 3 had roundworms (HCT 27–34%), 1 had tapeworms (HCT 35%), 1 had coccidia (HCT 37%), and 1 was parvovirus positive (HCT 40%). Hematocrit differed significantly between adults and puppies (p < 0.01) and between adults and mideruption dogs (p < 0.01), whether infectious cases were included or excluded. Juvenile shelter dogs have lower HCT than adults, similar to prior reports. Further investigation into underlying cause and influence of infectious disease is warranted. ABSTRACT HM09 Point of care assessment of fibrinolysis using the viscoelastic coagulation monitor Armelle deLaforcade ; Elizabeth Rozanski Cummings School of Veterinary Medicine at Tufts University Hyperfibrinolysis (HF) has been increasing identified as pathologic process in a variety of critical illnesses in dogs. However, HF is challenging to detect using conventional assays. Thromboelastography (TEG), modified with the addition of Tissue Factor (TF) and tissue plasminogen activator (TPA) has been described as a sensitive marker of fibrinolysis. However, TEG is not widely available in practice, and when available, requires specialized training and equipment to accurately perform the assay. The Viscoelastic Coagulation Monitor (VCM) has recently been introduced as a cartridge based viscoelastic test which removes the requirement for specialized equipment and training. The VCM is marketed as a point of care test with fresh whole blood. The goal of this study was to evaluate the effect of the addition of TPA to fresh whole blood in VCM cartridges. VCM produces results similar to conventional TEG, but are named Clot Time (CT), defined as when clot initially forms; Clot formation time (CFT) defined as when there is 10% amplitude of the clot from baseline; Angle defined as angle of the clot curve, maximum clot formation (MCF) defined as the firmness of the clot; A10 and A20 are the amplitude of the clot at 10 and 20 minutes after CT; while LI (lysis index) 30 and LI 45 represent the amplitude of the clot at 30 and 45 minutes after clot time as a percentage of the MCF. Healthy dogs were enrolled. A 2 ml sample of blood was collected. 500 μl was immediately placed in a VCM cartridge for point‐of‐care assessment of coagulation per the manufacturer's instruction. 400 μl of FWB was additionally placed into a vial containing 25 IU TPA, inverted 5 times, and then placed into a VCM cartridge. Results for VCM parameters were compared between treatment using a paired T‐test, with a p value of <0.05 considered significant. Eleven dogs were enrolled. There was no difference between CT, CFT, Alpha, A10, and A20 following the addition of TPA. However, the LI 30 and LI 45 were significantly affected by the addition of the TPA. The addition of TPA to FWB results in accelerated fibrinolysis as assessed by the VCM analyzer. Further investigation of the modified assay in dogs with evidence of hemorrhage is warranted. ABSTRACT HM10 Reactive oxygen species production and biomarkers of oxidative stress in anemic dogs Andrew Woolcock; Andrea Santos; Priscila Serpa; George Moore; John Christian Purdue University Oxidative stress has a role in the pathophysiology of multiple disease processes including anemia, and may contribute to ongoing red blood cell injury in hemolytic states. ROS are increased and antioxidant systems are depleted in people with autoimmune‐hemolytic anemia (AIHA), as well as anemia of chronic inflammatory disease. The role of oxidative stress in canine anemia is minimally understood. Glutathione peroxidase is reduced in anemic people, and was identified to be reduced in anemic dogs, but no association with hemolysis was noted. A novel assay for direct measurement of intraerythrocytic ROS by flow cytometry was recently validated, and shows promise for identification of ROS in canine disease states, including anemia. The objective of this study was to evaluate intraerythrocytic ROS production, as well as glutathione and vitamin E concentrations in anemic dogs. We hypothesized that anemic dogs would have increased ROS detected by flow cytometry, and decreased concentrations of glutathione and vitamin E when compared to controls. We further hypothesized that markers of oxidative stress would be different in dogs with hemolytic anemia when compared to dogs with non‐hemolytic anemia. Dogs were recruited from the hospitalized population of the veterinary teaching hospital. Dogs were eligible for inclusion to the study if their hematocrit or packed cell volume were <30%. Once included, medical records were reviewed to determine the most likely cause for the anemia. Causes were classified as either non‐hemolytic or hemolytic. A second population of healthy control dogs was recruited as well. Forty‐eight anemic dogs were included in the study, with 11 diagnosed with immune‐mediated hemolytic anemia, and 37 diagnosed with non‐hemolytic causes for their anemia. 20 healthy dogs were included in the study. Data were non‐parametrically distributed with summary descriptive statistics presented as median [range] and assessed with the Wilcoxon rank sum test. Median GSH:GSSG values from plasma and hemolysate samples of anemic and non‐anemic, healthy dogs, further divided into those with hemolytic and non‐hemolytic anemias. Healthy dogs were found to have significantly higher RBC GSH:GSSG when compared to anemic dogs of both causes (Table 1, p < 0.0001). Dogs with hemolytic anemia had lower GSH:GSSH compared to dogs with non‐hemolytic anemia, but this difference did not reach significance (p = 0.081). Dogs with hemolytic anemia had significantly higher plasma GSH:GSSG when compared to dogs with non‐hemolytic anemia and healthy dogs (both p < 0.0001). There was no difference in intracellular ROS or vitamin E between groups. This study demonstrated a significant depletion of glutathione in anemic states, especially in dogs with hemolytic anemia. While the use of flow cytometry to label intracellular ROS did not find differences between groups, this method still shows promise. Prospective investigation of oxidative stress in immune‐mediated hemolytic anemia is warranted, with an evaluation of the effect of antioxidant supplementation on these parameters.   ABSTRACT HM11 Identification of five new feline erythrocyte antigens based on the presence of naturally occurring alloantibodies Marie Binvel 1; Julie Arsenault1; Boris Depré2; Marie‐Claude Blais1 1Faculté de médecine vétérinaire, Université de Montréal; 2Adomvet Urgences vétérinaires Since the discovery of the feline Mik antigen, several studies have described blood incompatibilities unrelated to the AB system. Based on the presence of naturally occurring alloantibodies (NOAb), the purpose of this study was to begin mapping the corresponding feline erythrocyte antigens (FEA) behind these incompatibilities. By groups of six, 274 transfusion‐naïve cats were prospectively evaluated for the presence of alloantibodies using a gel column crossmatch test. When non‐AB‐related alloantibodies were detected in a cat, its plasma was used to assess the presence or absence of the corresponding antigen in cats included thereafter in the study (blood typing). Plasma from 18 of 263 type‐A cats (6.8%) caused 49 incompatible results out of 1257 crossmatches performed (3.9%). Presence of NOAb was statistically associated with an age of <2 years (p = 0.04). Using 7 of the 18 alloantibodies, systematic blood typing was performed, and results compared. Based on agreement analysis, 3 NOAb appeared to correspond to the same antigen (k3 0.64); hence the identification of 5 different putative FEA (numbered in order of identification). FEA 1, 4, and 5 were most frequent with a prevalence of 84%, 65%, and 96%, respectively. Only FEA 1 was significantly associated with NOAb (p = 0.005), which were observed in 8 of 43 FEA 1‐negative cats (19%). This study represents a first step of FEA's identification outside the AB system. Because of its prevalence and association with NOAb, FEA 1 may correspond to the lost Mik antigen. Banked alloantibodies will facilitate future studies, notably regarding their clinical relevance. ABSTRACT HM12 Comparison of dogs treated for primary immune‐mediated hemolytic anemia in Tuscany, Italy and Texas, USA George Lubas 1; Unity Jeffery2; Chiara Alaimo3; Giulia De Feo3; Alessandra Gavazza4 1Department of Veterinary Sciences, University of Pisa; 2College of Veterinary Medicine and Biomedical Sciences; 3University of Pisa; 4University of Camerino Large‐scale studies are needed to determine optimal treatment for canine immune‐mediated hemolytic anemia (IMHA). Multicenter studies reduce the time for case enrollment, but differences in disease severity and outcome could complicate their interpretation. This retrospective study compared clinical characteristics between dogs treated for IMHA by veterinary teaching hospitals in Tuscany, Italy and Texas, USA between 2010 and 2018. As the two institutions used different diagnostic criteria, Tuscany cases (n = 48) were included if flow cytometry was positive for anti‐erythrocyte antibodies and/or marked spherocytosis was reported. Texas cases (n = 43) were included if there was clinical evidence of hemolysis and marked spherocytosis and/or a positive saline agglutination test. Cases were excluded if a secondary IMHA was evidenced. Categorical data was compared by Chi‐squared test and continuous data by Mann‐Whitney test. The two populations did not differ significantly in age, but Texas dogs were more commonly neutered and had lower bodyweight. Chihuahuas and mixed breed dogs were most common in Texas and mixed breed dogs and Cocker Spaniels in Tuscany. Median hematocrit, erythrocyte regeneration response, occurrence of spherocytes and hyperbilirubinemia were not significantly different. Hemolyzed plasma and bilirubinuria were more common in Texan cases. CHAOS scores were not significantly different between groups. Texan cases were more likely to be hospitalized at initial presentation, but there was no difference in survival to discharge between the two locations. Dogs treated for primary IMHA in a European or North American location were broadly similar, suggesting cases from both locations could be combined in future clinical trials. ABSTRACT HM13 Chronic low‐dose rapamycin does not cause red blood cell microcytosis in middle‐aged, large breed dogs Jeremy B. Evans 1; Ashley Morrison1; Unity Jeffery1; Daniel Promislow2; Matt Kaeberlein2; Kate Creevy1 1Veterinary Teaching Hospital, Texas A&M; 2University of Washington Rapamycin is a macrolide antibiotic that inhibits the mammalian target of rapamycin (mTOR), a protein complex involved in multiple metabolic pathways. Due to its ubiquitous nature, disruption of the mTOR complex via rapamycin has numerous systemic effects, including immunosuppression, anti‐proliferative effects, and extension of lifespan in laboratory models. However, side effects, such as dyslipidemias and red blood cell microcytosis have been reported in humans and mice. This study aimed to determine the prevalence of progressive red blood cell microcytosis in middle‐aged, large breed dogs who received long‐term, low‐dose oral rapamycin. Seventeen dogs (10 spayed females, 1 intact female, and 6 castrated males) were randomly assigned to receive rapamycin (0.025 mg/kg) or a placebo orally every Monday, Wednesday, and Friday for 6 months. All enrolled dogs underwent complete evaluations (physical exam, chemistry, CBC, urinalysis, and echocardiogram) at baseline, 3 months, 6 months, and 12 months (i.e., 6 months after discontinuation of treatment), and erythrocyte mean corpuscular volume (MCV) was recorded for each visit. There was no significant difference in MCV between the control and rapamycin treated groups at baseline (71.4 fL vs. 72.0 fL, respectively; p = 0.56), 3 (70.9 fL vs. 70.9 fL; p = 0.99), 6 (70.1 fL vs. 69.8 fL; p = 0.74), or 12 months (69.3 fL vs. 70.4 fL, p = 0.14). Additionally, there were no significant differences in the change in MCV between groups over the 6 month period (−1.3 fL [control] vs. −2.2 fL [rapamycin]; p = 0.18). In the cohort receiving rapamycin, there was a significant reduction in mean MCV from baseline to 6 months (72.0 fL vs. 69.8 fL; p = 0.03), but there was no significant difference in MCV between 6 and 12 months (69.8 fL vs. 70.4 fL; p = 0.54). In the control group, a significant decrease in MCV was observed from baseline to 12 months (71.4 fL vs. 69.3 fL; p = 0.04), a finding that reflects the need for more study subjects in order to better assess the potential of rapamycin‐induced changes in MCV in healthy dogs.   ABSTRACT HP01 Evaluation of coagulation in dogs with gallbladder mucoceles Michelle Pavlick 1; Cynthia Webster2; Dominique Penninck2; Armelle DeLaforcade2 1Newtown Veterinary Specialists; 2Tufts University Gallbladder mucoceles (GBM) are a common biliary disorder in dogs and are associated with inflammatory and thrombotic complications. Limited information is available on their coagulation status. The aim of this study was to assess coagulation in dogs with GBM. Twenty‐three dogs with GBM identified on ultrasound were prospectively enrolled. Blood was collected at the time of GBM identification for determination of complete blood count, biochemical panel, packed cell volume, prothrombin time (PT), activated partial thromboplastin time (aPTT), factor VIII activity, fibrinogen, D‐dimers, thromboelastrography (TEG), protein C activity (PC), antithrombin activity (AT), and von Willebrand's factor activity (vWF). Overall, when compared to the hospital generated reference range population, dogs with GBM had significantly decreased K values and increased angle, MA and G (p < 0.001). Based on G value, 19/23 dogs (82.6%) were classified as hypercoagulable and 4/23 (17.4%) were classified as normocoagulable. Four of 23 (17.3%) of dogs were classified as hyperfibrinolytic based on increased Ly 60 values. Plasma based coagulation tests showed coagulation changes consistent with hypercoagulability such as hyperfibrinogenemia (8/23), thrombocytosis (9/23) and increased D‐dimers (4/13). Increased PC activity (20/24) and AT activity (9/23) were seen. The PT was normal 21/22 dog but the aPTT was prolonged in 8/22. vWF was not increased in any dog while Factor VIII was increased in 3/23 dogs. In conclusion, dogs with ultrasonographically identified GBM have changes in whole blood kaolin‐activated TEG supporting a hypercoagulable state although traditional plasma‐based coagulation testing might suggest that a more complex state of hemostasis exists. ABSTRACT HP02 Dogs with chronic hepatitis have altered amino acid profiles compared to healthy dogs Robert Kyle Phillips 1; Amanda Blake2; Yuri Lawrence3; Jan Suchodolski2; Jörg Steiner2; Jonathan Lidbury2 1GI Lab, Texas A&M University; 2Texas A&M University; 3Austin Veterinary Emergency and Specialty Center The liver plays a central role in protein metabolism, and abnormalities of serum amino acid (AA) concentrations contribute to the development of sequelae to chronic hepatitis (CH), such as hepatic encephalopathy. Consequently, measurement of serum AA concentrations may better our understanding of the pathogenesis of CH in dogs, as well as serving as potential diagnostic and/or prognostic biomarkers. The purpose of this study was to compare serum AA profiles between dogs with CH and healthy control dogs. Serum samples were collected from 10 dogs with histologically confirmed CH and from 38 healthy control dogs. Serum AA were measured with a Biochrom 30+ (Biochrom Ltd., Cambridge, UK) amino acid analyzer. The concentration of each AA between groups was compared using a Mann‐Whitney test and corrected for multiple comparisons using the Benjamini‐Hochberg procedure. Significance was set at q < 0.05. Twenty‐eight AA were measurable in the serum samples. Serum concentrations of 13 AA were significantly increased in dogs with CH: glutamic acid, phenylalanine, asparagine, ornithine, serine, lysine, glutamine, histidine, citrulline, methionine, α‐aminobutyric acid, tyrosine, and aspartic acid. The serum concentration of hydroxyproline was significantly decreased in dogs with CH. Serum concentrations of the following AA were not significantly different between groups: alanine, valine, 1‐methylhistidine, proline, isoleucine, phosphoserine, leucine, threonine, glycine, arginine, tryptophan, α‐aminoadipic acid, 3‐methylhistidine, and hydroxylysine. Dogs with CH had altered serum AA concentrations compared to healthy control dogs. Serum concentrations of 13 of 28 measured AA were increased in dogs with CH, which may be attributable to increased protein turnover and/or diminished AA catabolism. Further investigation to determine if these alterations constitute a unique serum AA profile for patients with CH that is distinguishable from dogs with other forms of hepatic disease is warranted. ABSTRACT HP03 Gastroduodenal ulceration in canine liver disease Kirsten Cooke; Allison O'Kell; Alexander Gallagher College of Veterinary Medicine, University of Florida Although liver disease is frequently cited as a cause of gastroduodenal ulceration (GDU) in dogs, studies regarding GDU and esophageal varices (EV), another possible sequelae of liver disease, are limited. The objective of this study was to document the presence of GDU and EV in dogs with liver disease. Dogs that underwent liver biopsy and/or CT angiography to diagnose congenital or acquired liver disease were enrolled. All dogs had gastroduodenoscopy performed with photographic and video documentation in a standardized fashion. Lesions (hemorrhage, erosions, ulcers) in the esophagus, stomach, and duodenum were scored based on a grading scale and presence of EV was recorded. Dogs were categorized into 4 groups according to the cause of liver disease (inflammatory disease, cirrhosis, congenital, other) and the total endoscopic score was compared among the groups using a Kruskal‐Wallis test. The presence or absence of ulcers and/or erosions was compared among the groups using a Fisher's exact test. Forty dogs were enrolled in the study with the following distribution: 12 congenital, 13 inflammatory, 3 cirrhosis, and 9 other. Four dogs had GDU (11%), nine dogs had erosions and/or GDU (22.5%), and 1 dog had EV (2.5%). There was no difference in total endoscopic score between the groups (p = 0.21) or in the proportion of dogs with ulcers and/or erosions versus those without (p = 0.25). GDU and EV were not common in this population of dogs with liver disease. Further studies are warranted to confirm these findings in larger numbers of dogs with specific disease etiologies. GDU and EV were not common in this population of dogs with liver disease. Further studies are warranted to confirm these findings in larger numbers of dogs with specific disease etiologies. ABSTRACT HP04 Intracellular distribution of copper in liver specimens from cats Punyamanee Yamkate 1; David Twedt2; Jan Suchodolski1; Joerg Steiner1; Jonathan Lidbury1 1Gastrointestinal Laboratory, College of Veterinary Medicine, Texas A&M University; 2College of Veterinary Medicine and Biomedical Sciences, Colorado State University The intracellular distribution of copper in the liver has been investigated in many species, including rats, sheep, humans, and dogs. Intracellular copper distribution has been reported to differ in patients with copper hepatopathy compared to those of healthy subjects, providing important insight into the pathogenesis of this condition. However, hepatic copper distribution has not previously been reported in cats. Therefore, the aim of this study was to assess the intracellular copper distribution in liver specimens from cats with copper concentrations within or above the reference interval. Thirteen frozen liver specimens collected from cats were available for this study, 6 with copper concentrations within and 7 with copper concentrations above the reference interval (<180 μg/g dry weight). Each specimen of frozen liver tissue was divided into two equal portions. The first portion was kept for copper quantification. The other portion was homogenized and was separated into fractions (nuclear, large granule, microsomal, and cytosolic) using differential centrifugation. Copper concentrations in liver specimens and liver fractions were measured using flame atomic absorption spectroscopy. The distribution of copper among fractions was calculated and compared between liver specimens with copper concentrations within or above the reference interval using Mann Whitney test. Statistical significance was set as p < 0.05. For liver specimens with copper concentration within the reference interval, median (range) percentage of copper in each of the 4 fractions was as follows: nuclear, 23.8% (11.6–41.6); large granule, 11.6% (9.4–27.8); microsomal, 4.2% (2.2–8.7); and cytosolic, 58.6% (44.5–62.8). For liver specimens with copper concentration above the reference interval, median (range) percentage of copper in each of the 4 fractions was as follows: nuclear, 20.2% (11.2–35.8); large granule, 19.1% (2.6–26.2); microsomal, 8.2% (1.3–9.7); and cytosolic, 56.1% (41.8–79.2). There was no significant difference in copper distribution for each fraction between cat liver specimens with hepatic copper concentrations within or above the reference interval (p > 0.36). Our findings indicate that, similar to other species, intracellular copper is predominantly found in the cytosolic and nuclear fractions in liver specimens from cats. The distribution of copper in liver specimens from cats with copper concentrations above the reference interval was not significantly different to those with copper concentrations within the reference interval. Consequently, further investigation of hepatic intracellular copper distribution in a greater number of liver specimens from cats is warranted. ABSTRACT HP05 Approach to the diagnosis of hepatocutaneous syndrome in dogs: A retrospective study and systematic review Karah C. Burns DeMarle 1 ; Lluis Ferrer2; Dominique Penninck1; Cynthia Leveille‐Webster1 1Cummings School of Veterinary Medicine, Tufts University; 2Autonomous University of Barcelona Hepatocutaneous syndrome (HCS) is a rare and often fatal disease seen in dogs characterized by skin lesions (superficial necrolytic dermatitis [SND]) and associated hepatopathy. Although various combinations of clinical signs, biochemistry tests, imaging findings and skin and hepatic histopathology have been used to diagnose this syndrome, there is currently no consensus on which combination would enable the most timely and non‐invasive method for diagnosis. In order to accomplish this, medical records were reviewed retrospectively for dogs with skin biopsy proven HCS (n = 24) and data were compared to cases found by systematic review of the literature (n = 105). The most consistent findings were ulcerative‐crusted lesions affecting paw pads or mucocutaneous junctions (103/103, 100%), marked plasma hypoaminoacidemia (50/50, 100%) and the presence of a “honeycomb‐like” appearance to the liver on ultrasound (62/63, 98%). Six out of 23 (26%) of the dogs in the retrospective study had marked keratinocyte apoptosis, a finding associated with the development of diabetes mellitus. A literature search confirmed that the marked plasma hypoaminoacidemia seen in dogs with HCS is unique and has not been reported in other hepatic disease (n = 6 manuscripts) or in non‐hepatic disorders (n = 5 manuscripts). An algorithm for diagnosing HCS was developed which involves sequential identification of characteristic skin lesions, plasma hypoaminoacidemia and the presence of a honeycomb‐like pattern of the liver on ultrasound. This diagnostic approach simplifies the diagnostic pathways used in the literature and permits earlier identification of HCS cases before the painful lesions prompt the compassionate decision for euthanasia. ABSTRACT HP06 Validation of an in‐clinic assay for the measurement of canine and feline bile acids Elizabeth Schooley; Eric Steva IDEXX Laboratories Inc. This study evaluates IDEXX Catalyst® Bile Acids (CatalystBA) for canine and feline bile acids measurement. Serum samples, originally submitted for clinical purposes, from 73 dogs and 45 cats were obtained from IDEXX Reference Laboratories (IRL). Samples were provided in accordance with IRL Terms and Conditions. Samples were analyzed using CatalystBA, once on a Catalyst One® analyzer, once on a Catalyst Dx® analyzer and twice using the Diazyme Total Bile Acids Assay (Enzyme Cycling Method) run on the Beckman Coulter AU5800 analyzer (RefMethod). Each CatalystBA result was paired with the corresponding mean RefMethod result. Testing was completed at IDEXX. Precision was evaluated with a 10‐day protocol run across 4 Catalyst instruments. RefMethod median bile acids was 22.3 μmol/L; range: 1.0 to 155.8 μmol/L. CatalystBA median bile acids was 21.0 μmol/L; range: 1.1 to 177.8 μmol/L. No statistical difference existed between concentrations obtained by the two methods (p = 0.86; Wilcoxon signed ranks). Method comparison results are reported with 95% confidence limits in parentheses. Passing‐Bablok regression analysis: intercept −1.04 μmol/L (−1.49 to −0.74); slope 1.05 (1.02 to 1.09); Tau 0.88. Pearson's correlation coefficient (r): 0.99. Results were assigned to one of three categories (Table 1). Calculation of percent concordance between the assays showed excellent agreement (92.6%) on result classification. Results of precision testing are outlined in Table 2. This study confirms minimal bias, good precision and concordance, as well as excellent correlation with the RefMethod and provides confidence that CatalystBA shows strong performance for in‐clinic measurement of canine and feline bile acids.   ABSTRACT IM01 RNA sequencing of dogs with primary immune‐mediated hemolytic anemia Corie Borchert 1; Aimee Brooks2; Adam Herman3; Steven Friedenberg1 1University of Minnesota, Twin Cities; 2Purdue University; 3Minnesota Supercomputing Institution The immunologic and cellular mechanisms that trigger the onset of immune‐mediated hemolytic anemia (IMHA) in dogs are largely unknown. Given the significant morbidity and mortality caused by IMHA in dogs, further investigation into its underlying etiology is warranted. For many diseases, transcriptome‐wide gene expression studies have proven to be a powerful tool to inform our understanding of disease pathophysiology and identify novel therapeutic targets. In this study, we hypothesized that RNA sequencing of dogs with IMHA would reveal marked dysregulation of genes and gene pathways related to erythropoiesis and immune system function. We collected whole blood samples in an RNA stabilizing medium from 18 dogs with a new diagnosis of primary IMHA and an equal number of breed‐ and age‐matched controls from two tertiary care referral institutions. Total RNA was extracted from each sample, depleted of hemoglobin and ribosomal RNA using sequence‐specific capture probes, barcoded, pooled, and sequenced in a 50 base‐pair paired‐end read configuration to a target depth of 60 million reads per sample. Analysis of differentially expressed genes between cases and controls revealed greater than 8‐fold (B‐H p < 0.05) upregulation of many genes related to erythrocyte production, the complement system, and neutrophil function in affected dogs. In particular, several genes encoding for erythrocyte membrane proteins which have been associated with hemolytic anemia in humans were significantly upregulated, as well as scramblases which translocate phospholipids across erythrocyte cell membranes. Unexpectedly, many genes and pathways related to lymphocyte function were markedly downregulated, which could point to differences in the activation states of circulating vs. organ‐resident lymphocytes in IMHA patients. Gene co‐expression network analysis identified groups of genes that are strongly associated with changes in reticulocyte (p = 5 × 10−6), neutrophil (p = 6 × 10−5), and eosinophil (p = 2 × 10−6) count in affected dogs. Further studies are warranted to validate these findings in a larger population of affected dogs, and to determine which dysregulated genes or pathways might be potential targets for therapeutic intervention. ABSTRACT IM02 Proteomic analysis of canine vaccines George E. Moore 1; Jackeline Franco2; Uma Aryal2; Harm HogenEsch2 1College of Veterinary Medicine, Purdue University; 2Purdue University Canine vaccines provide protection against important zoonotic and non‐zoonotic infectious disease by stimulating immune responses to vaccine antigens. Unintended or adverse immune responses may develop, however, against protein antigens that are present in the vaccine but do not originate from the pathogen(s) for which the vaccine was designed. Dogs with adverse reactions to vaccines have demonstrated immunoreactivity to proteins of bovine origin, e.g., from fetal calf serum, but specific protein components of canine vaccines have not been elucidated. The objective of this study was to use proteomic analysis to qualitatively and quantitatively identify protein components of commonly used canine vaccines. The vaccines analyzed were purchased commercially and produced by 4 major manufacturers. The vaccines included 8 rabies vaccines (four with 1‐year duration of immunity and four with 3‐year duration of immunity), 9 multivalent distemper‐adenovirus 2, parvovirus, parainfluenza, and leptospirosis vaccines, and 7 Lyme (Borrelia burgdorferi) vaccines. For vaccines designed to be reconstituted, the lyophilized and liquid components were analyzed separately. This resulted in 29 products for proteomic analysis; all vaccines, lyophilized, and liquid components were processed in duplicates. Proteins were acetone precipitated, reduced with 10 mM dithiothreitol, alkylated with 20 mM iodoacetamide and then digested with a trypsin and Lys‐C mix before liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) analysis using the UltiMate 3000 RSLC nano System coupled to the Orbitrap Fusion Lumos Mass Spectrometer. LC‐MS/MS data were searched against Bos taurus protein database using MaxQuant (version 1.6.3.3) for protein identification and label‐free relative quantitation (LFQ intensities). At MS/MS spectral counts >5, there were 357 different proteins identified (molecular weight range 5–587 kDa). All rabies vaccines had significantly (>2–8 fold) more proteins identified than were present in the other types of vaccines. Bovine serum albumin (BSA‐69 kDa) was the most common protein identified but varied in quantity by vaccine and manufacturer. Other commonly identified proteins, also varying by vaccine and manufacturer, included α‐2‐HS‐glycoprotein (38 kDa), α‐1‐antiproteinase (46 kDa), and α‐fetoprotein (68 kDa). Proteomic analysis of vaccines identified specific, yet diverse, proteins that may initiate potentially beneficial or adverse immune responses following vaccination. ABSTRACT IM03 Gene expression of immunoinflammatory and immunological status of obese dogs before and after weight loss Vivian Pedrinelli 1; Thiago Vendramini1; Henrique Macedo1; Andressa Amaral1; Mariana Rentas1; Matheus Macegoza1; Rafael Zafalon1; Lígia Mesquita1; Julio Balieiro1; Karina Pfrimer1; Raquel Pedreira2; Cristiana Pontieri2; Cristina Gomes1; Marcio Brunetto1 1University of Sao Paulo; 2Grandfood Industry and Commerce Ltd Adipose tissue actively participates in inflammation and immunity, and several defense cells of the organism may, therefore, be involved in the diversity found between obese and ideal weight individuals. Thus, the present study aimed to evaluate the gene expression profile of immunoinflammatory response and the lymphoproliferation of obese dogs before and after weight loss. Eight female dogs, neutered, aged between 1 and 8 years, obese, with body composition determined by the deuterium isotope dilution method were included. The obese dogs were enrolled in a weight loss program and after losing 20% of their initial weight became a second experimental group. A third experimental group consisted of eight female dogs, neutered, aged between 1 and 8 years and with ideal composition and body condition score ideal. Procedures were previously approved by the Animal Use Ethics Committee (AUEC) of the School of Veterinary Medicine and Animal Science of the University of São Paulo (protocol number 4668091214). Gene expression of immunoinflammatory cytokines (resistin, leptin, adiponectin, TNF‐α, IL‐6, IL‐8, and IL‐10) was assessed by qRT‐PCR and immunity was assessed by lymphoproliferative response using the flow cytometry technique. The obese group presented increased gene expression of resistin, adiponectin, and IL‐8 in relation to the weight loss group. Weight loss resulted in an increase in the lymphoproliferation rate (18.48%) compared to obese dogs at the beginning of the study (10.71%) (p = 0.004). These results indicate that weight loss modulates the immunoinflammatory response of obese dogs and may present important benefits to health and longevity of dogs. ABSTRACT IM04 Effect of distemper‐adenovirus‐2‐parainfluenza‐parvovirus vaccination on platelet numbers and development of anti‐platelet antibodies in healthy dogs Maggie Williams; Michael Lappin; Nida Chornarm; Matt Khorsand; Melissa Brewer; Jennifer Hawley; Sarah Shropshire Colorado State University Immune thrombocytopenia (ITP) can occur when platelets are destroyed as a result of antibody‐mediated mechanisms. In humans, ITP has been associated with the measles, mumps, and rubella (MMR) vaccine. Canine distemper, adenovirus‐2, parainfluenza, and parvovirus (DA2PP) vaccines contain a similar paramyxovirus virus to those in MMR. A link between vaccination with DA2PP and thrombocytopenia has been proposed although a recent retrospective study failed to find a correlation with clinical ITP and recent vaccination. There is increasing concern for a link between vaccination and immune‐mediated conditions in dogs but a causal relationship between vaccination and ITP, determined by anti‐platelet antibodies (APA), has not been investigated. The objective of this study was to determine if administration of modified live DA2PP vaccines induces a thrombocytopenia and development of APA in a population of healthy, client‐owned dogs. Thirty client‐owned healthy adult dogs were randomly divided into 1 of 3 DA2PP vaccine groups (n = 10/group). On day 0, all dogs had a physical examination, CBC, chemistry, and APA flow cytometry followed by DA2PP vaccination. On day 10, repeat platelet count, mean platelet volume (MPV), and APA flow cytometry were performed. On day 0, one dog was positive for APA (26.1% IgG) with normal platelet count and was excluded from the study; all other dogs were negative for APA (<10% IgG) and had normal platelet counts. On day 10, no dogs were thrombocytopenic or had clinical signs of bleeding. From day 0 to 10, platelet counts increased by a mean of 43 k/μL (range − 36 to 214; SD 48.7, p < 0.001) and percent IgG increased by mean of 1.72% (range −4.13 to 6.72, SD 2.9, p = 0.0037). One dog became weakly positive for APA (10.7% IgG; weak positive range 10–14%) but had an increase in platelet count and the remaining dogs were negative for APA. There was no significant change in MPV. In this population of healthy, client‐owned dogs, vaccination with commercial DA2PP vaccines was not associated with development of thrombocytopenia or clinically relevant APA formation. Additional longitudinal studies evaluating platelet count and APA after vaccination are warranted. ABSTRACT ID01 Canine leishmaniasis in North America: Imported and autochthonous cases, 2006–2019 Taylor Gin 1; Edward Breitschwerdt2; Barbara Qurollo3 1College of Veterinary Medicine, Texas A&M University; 2NCSU; 3Department of Clinical Sciences, NCSU Sand fly transmission of Leishmania infantum, a protozoa that causes a potentially life‐threatening infectious disease in dogs and humans in many parts of the world, has not been definitively documented in the United States or Canada. Infection with L. infantum has been reported commonly in foxhounds throughout North America, but only rarely in other dog breeds. A convenience sample of dogs tested by L. infantum immunofluorescent antibody (IFAT), Leishmania PCR, or both diagnostic assays was established for this study by review of a database containing canine vector‐borne diseases (CVBD) diagnostic testing results performed between 01/04/2006 and 05/22/2019 at the North Carolina State University (NCSU), College of Veterinary Medicine (CVM), Vector‐borne Disease Diagnostic Laboratory (VBDDL). We report demographics and travel history obtained through email or phone contact with the primary veterinarian for dogs positive for L. infantum based on positive serology and/or PCR. Over this time period, 126/1,961 (6.4%) of dogs tested by the NCSU‐CVM‐VBDDL were serologically (n = 100) or PCR (n = 60) positive for L. infantum. Information related to travel history was available for 70/126 (55.6%) dogs. Sixty (85.7%) dogs had history of travel outside of the US or Canada, whereas 10 (14.3%) dogs had no travel history outside of North America, including 3 PCR positive dogs. Importantly, 116/126 (92%) of L. infantum positive dogs were breeds other than foxhounds. L. infantum was detected in many non‐foxhound breeds, some of which had no reported travel history outside of the US or Canada. Increased Leishmania diagnostic testing and disease surveillance in dogs are essential for monitoring potential emergence of this zoonotic infectious disease in North America. ABSTRACT ID02 Heterobilharzia Americana infection in dogs: Clinical features and outcome in 60 cases (2010–2019) Amber M. Graham 1; Valentina Moshnikova2; Amy Davenport3; Lindsey Gilmour1; Michelle Fabiani3; Audrey Cook1 1Texas A&M University; 2University of Minnesota; 3Gulf Coast Veterinary Specialists Fecal PCR testing has simplified the diagnosis of Heterobilharzia americana in dogs. The purpose of this retrospective study was to provide updated information regarding the clinical features of this infection. Medical records at two hospitals were searched for patients with schistosomiasis, and data were collected regarding signalment, history, diagnostic results, treatment, and outcome. Sixty dogs were diagnosed using fecal PCR (n = 49), PCR and histology (n = 3), histology (n = 5), or fecal floatation (n = 3). Mean age was 7.5 years (range: 0.6–17.2) and median body weight was 23.2 kg (range: 3.4–49). Forty‐one dogs presented for vomiting +/− diarrhea; eight for weight loss +/− anorexia. Laboratory data were available for 54 dogs: hypercalcemia was noted in 4/54; azotemia in 10/52; hypoalbuminemia in 14/54; hyperglobulinemia in 18/54. Eosinophil count was >500/μL in 22/52. Increased ALP (n = 13; median: 306 IU/L; range: 161–1795) and ALT (n = 7; median: 335 IU/L; range: 131–1447) activities were noted in 14/47. Transabdominal ultrasonography revealed pin‐point hyperechoic foci in the small intestine +/− liver +/− mesenteric lymph nodes in 38/59 dogs; effusion was noted in 14/59. Fifty‐six dogs received oral praziquantel for 2–3 days (median dose: 27 mg/kg q 8 hr). Concurrent medications included fenbendazole (40/56) and anti‐inflammatory doses of prednisone (12/56). Follow‐up PCR was negative in 11 dogs; 5 were PCR positive and retreated. Six‐month survival data was available for 34 treated dogs: 25 were alive, 2 died acutely during treatment, 7 died or were euthanized due to their infection (n = 3) or of unrelated causes (n = 4). Clinical features of schistosomiasis are variable and non‐specific. It is noteworthy that <10% of dogs were hypercalcemic and two died acutely during treatment. Schistosomiasis should be considered in dogs in endemic areas with gastrointestinal signs, weight loss, elevated liver enzymes or consistent ultrasound changes. ABSTRACT ID03 Evaluation of canine parvovirus neutralizing antibody (KIND‐030) as a prophylactic and therapeutic treatment in puppies Ellen R. Ratcliff 1; Laurie Larson2; Allyson Avenatti1; Stephanie Pierce1; Tianhua Hu1; Melinda Poole1 1Kindred Biosciences, Inc.; 2School of Veterinary Medicine, University of Wisconsin‐Madison The primary purpose of this proof‐of‐concept study was to evaluate the effectiveness of canine parvovirus (CPV) neutralizing antibody (KIND‐030) as a prophylactic and therapeutic treatment in puppies. KIND‐030 is a monoclonal antibody. It is under clinical investigation and has not received approval by the USDA. Eight purpose‐bred, CPV‐2 seronegative, healthy beagle puppies aged 11 weeks were randomly allocated to four open‐label groups. No treatment beyond study drug was permitted. Groups 1 (n = 2, IV 5 mg/kg) and 2 (n = 2, SC 5 mg/kg) received treatment with KIND‐030 on Day 1. All four groups were inoculated with a challenge dose of 106 TCID50 dose of virulent CPV‐2 on Day 4. Group 3 (n = 2) received KIND‐030 IV 5 mg/kg upon detection of CPV‐2 in feces as confirmed via cage‐side ELISA. Group 4 (n = 2) did not receive KIND‐030 treatment. Survival: Groups 1 and 2 puppies remained healthy throughout the study. Group 3 puppies survived and recovered during the study period. Group 4 puppies were severely affected by CPV infection and euthanized for humane reasons before study completion. SNAP Test: In Groups 1 and 2, none of the puppies had a positive SNAP test during the study. In Group 3, both puppies had positive SNAP tests on Day 7. Group 4 puppies had a positive SNAP test on Day 7 (n = 1) and Day 8 (n = 1). Adverse Events: There were no adverse events and no injection site reactions in Groups 1 and 2. Following KIND‐030 treatment, Group 3 did not exhibit any remarkable adverse events. Group 4 puppies demonstrated symptoms consistent with CPV infection. In this proof‐of‐concept study, prophylactic administration of KIND‐030 prior to challenge protected 100% of puppies from CPV‐2 infection. In addition, 100% of puppies given therapeutic administration of KIND‐030 after confirmed CPV infection survived and recovered. ABSTRACT ID04 A novel Rickettsia species infecting febrile dogs in the United States Barbara A. Qurollo 1; James Wilson1; Edward Breitschwerdt1; Nicholas Juhasz1; Henry Marr1; Joao Filpe de Brito Galvao2; Carmela Pratt3 1College of Veterinary Medicine, North Carolina State University; 2VCA Arboretum View Animal Hospital; 3Oklahoma Veterinary Specialists In the United States, tick‐borne Rickettsia rickettsii, causative agent of Rocky Mountain Spotted Fever (RMSF), is the only known cause of spotted fever group (SFG) rickettsioses in dogs. SFG Rickettsia, including R. parkeri, Rickettsia 364D and R. rickettsii are well‐documented causes of human SFG rickettsioses. If, or to what extent, other SFG Rickettsia are pathogenic in dogs is unclear, but serosurveys report high SFG Rickettsia seroprevalence in dogs in North America. In this study, we describe a novel Rickettsia sp. infecting three dogs with febrile illness and hematological abnormalities. All dogs were R. rickettsii IFA seroreactive and identical Rickettsia DNA sequences were amplified from their diagnostic blood specimens. Case 1 had acute onset fever with a rapid response to doxycycline. Case 2 had acute onset fever and neutrophilic polyarthritis. Case 3 had acute onset fever and a concurrent disease process that contributed to protein losing nephropathy. Case 3 was also febrile and seroreactive to Rickettsia by IFA one year prior to documentation of the novel Rickettsia sp. infection. Geographically, these cases were distributed among four states, including Tennessee and Arkansas (travel history case 1), Illinois (case 2) and Oklahoma (case 3). Tick exposure was documented in all three dogs and illness occurred during summer months. The novel Rickettsia sp. was confirmed by PCR amplification and sequencing of several Rickettsia genus targets. A multi‐locus Rickettsia spp. phylogenetic tree using 2,576 nucleotides concatenated from 5 regions within 3 genes (ompA, gltA, and 17 kDa) and 2 intergenic spacer regions (23S‐5S and mmpA‐purC) was assembled using the maximum‐likelihood method and Tamura‐Nei model. The novel Rickettsia sp. was most similar to R. heilongjiangensis and R. massiliae, tick‐borne human rickettsial pathogens. These three canine rickettsioses cases underscore the potential for canine infection with a previously undescribed vector‐borne pathogen in the United States and the utility of dogs as sentinels for the identification of emerging and potentially zoonotic tick‐borne pathogens. ABSTRACT ID05 Flea‐borne bacterial pathogens from free‐roaming cats and their fleas Erin W. Lashnits 1; Charlotte Manvell1; Hanna Berman1; William Swain2; Kelli Ferris1; Edward Breitschwerdt1; Benjamin Callahan1 1North Carolina State University; 2University of Wyoming Free‐roaming cats live at the interface between humans, their companion animals, local wildlife, and the parasites that infest these animals, creating novel opportunities for cross‐species pathogen transmission. The cat flea (Ctenocephalides felis) is the most common ectoparasite of free‐roaming cats and is the vector of transmission for multiple zoonotic bacterial pathogens, including Bartonella, hemotropic Mycoplasma, and Rickettsia species. The goal of this study was to determine the prevalence of flea‐borne bacterial pathogens in free‐roaming cats and their fleas across different geographic locations using both targeted real‐time PCR (qPCR) and 16S rRNA next generation sequencing (NGS). Fleas were collected from free‐roaming cats at spay and neuter clinics in northern California, Louisiana, and North Carolina. Tissue samples (ear tips and reproductive tissues including ovary, testicle, uterus, placenta, and fetus) were concurrently collected in North Carolina. Real‐time PCR was performed on DNA extracted from whole washed fleas and tissue samples, with primers for Bartonella ssrA and hemotropic Mycoplasma spp. 16S. Positive results were confirmed with Sanger sequencing and species identity determined based on alignment with the NCBI Local Alignment Search Tool (BLAST). A subset of 45 fleas from North Carolina (n = 33) and California (n = 12) also had whole‐flea eubacterial community composition determined using NGS targeting the V3‐V4 region of the 16S rRNA gene. By qPCR, 28% of C. felis (33/142) contained Bartonella spp. DNA. Bartonella was most common in fleas from North Carolina (20/28 positive, 71%), moderately common in fleas from Louisiana (13/44 positive, 30%), and relatively rare in fleas from northern California (2/67 positive, 3%; chi‐squared test of independence for each proportion p < 0.01). Based on 16S‐NGS on whole washed fleas, the most common pathogenic bacteria found were Bartonella and Rickettsia genera; a large proportion of fleas also carried Wolbachia spp. Microbiota community composition in this pilot set of fleas was associated with geographic region, confirming results from targeted qPCR. The sensitivity and specificity of 16S‐NGS (with targeted qPCR as the reference standard) for Bartonella spp. was 76% and 92% respectively. Based on targeted PCR and 16S‐NGS, no fleas contained hemotropic Mycoplasma spp. DNA. For 68 cats with ear tip tissue collected (all from North Carolina or Virginia), 21% were Bartonella PCR positive (most commonly B. clarridgeiae) and 16% were hemotropic Mycoplasma spp. PCR positive (most commonly M. haemominutum). Of the 68 cats sampled, only 21 had fleas collected: 14% (3/21) of these cats with fleas were Bartonella PCR positive, compared to 20% (5/25) of cats with no fleas collected (p = 0.71). In reproductive samples (173 tissue samples from 49 cats), Bartonella spp. DNA was qPCR amplified from 18% and hemotropic Mycoplasma from 8%. Our findings document geographic differences among flea‐borne bacterial pathogens, with Bartonella spp. most common in fleas from North Carolina cats. Hemotropic Mycoplasma spp. were not documented in fleas, despite infection being found in cats. Further investigations are needed to elucidate factors associated with the incidence of these important and potentially fatal flea‐borne diseases that affect both cats and humans worldwide. ABSTRACT ID06 The “backyard” identified as an environmental reservoir of blaNDM‐5 E. coli during a veterinary outbreak Stephen Cole; Jaclyn Dietrich; Shelley Rankin University of Pennsylvania Healthcare associated outbreaks of carbapenem‐resistant Enterobacteriaceae (CRE) have been associated with environmental reservoirs that include handwashing sinks, shower drains and medical equipment. There are limited reports of outbreaks of CRE in veterinary settings and little is known about the veterinary hospital epidemiology of these organisms. Results of point prevalence surveys (PPS) during the response to an outbreak of blaNDM‐5 positive Escherichia coli at a referral veterinary hospital in 2018–2019 suggested possible ongoing in‐facility transmission to animals. Since CRE is spread via the Oral‐Fecal route, we hypothesized that the outdoor elimination area or “backyard” that was shared by many patients served as a reservoir for infection. Samples were collected from an outdoor elimination area using sterile electrostatic cling cloths (Swiffer). The shoes of the sampler were tested before and after collection. Cloths were incubated at 37°C in 100–200 mL of buffered peptone water (BPW) in a WhirlPak for 16–24 hours and 10 μL subcultured to selective, chromogenic agar plates (CARBA, BioMerieux). 0.5 mL of the BPW enrichment b was added to 4.5 mL of tryptic soy broth supplemented with a 10 μg meropenem disc and incubated and subcultured as described above. Presumptive isolates were confirmed as E. coli with the Vitek2 GN Card and shown to produce a carbapenemase with the modified Carbapenem Inhibition Method (mCIM). Bacterial DNA extraction was performed and the isolates were tested with a loop mediated isothermal PCR assay that detects the NDM gene. Positive sites identified in the elimination area included multiple sections of the synthetic turf, metal and composite wood siding, a hose and “pooper scooper” that were stored on the turf. The metal door jamb and a rug leading from the area back into the clinical areas of the hospital were also positive. In addition, the shoes of the collector were negative prior to collection but positive following collection. All 10 environmental isolates were identified as E. coli and were positive for the NDM gene. This study suggests that the elimination area may have served as an environmental reservoir for CR E. coli during an outbreak at a veterinary hospital. To what degree patient‐to‐patient transmission played a role cannot be determined within the 16 patients with NDM‐5 E. coli identified by point prevalence testing. This study also demonstrated that the shoes of animal handlers can be contaminated. This could reintroduce CRE from outdoor elimination areas into the hospital environment and potentially expose more animals and people. Shared elimination areas should be considered high risk areas for nosocomial transmission of antibiotic resistant bacteria and that risk should also be considered for the people that accompany animals into this area. ABSTRACT ID07 Knowledge, attitudes and influencers of dog‐owners surrounding antimicrobials and antimicrobial stewardship in North America Madeleine R. Stein 1; Michelle Evason2; Jason Stull2; J McClure2 ; J. Scott Weese3 1University of Prince Edward Island; 2Atlantic Veterinary College; 3Ontario Veterinary College Antimicrobial resistance (AMR) in companion animals is a growing concern. Research on pet‐owner knowledge, attitudes, and influencers (KAIs) surrounding antimicrobials will elucidate education needs. Study objectives were to: (1) Quantify the individual influences of antimicrobial cost, method of administration, and drug importance in human medicine on dog‐owner preferences, and (2) Determine KAIs of dog‐owners surrounding antimicrobials and antimicrobial stewardship. Data were collected through an online survey targeting three dog‐owner participant groups. These consisted of individuals residing in (1) Canada, (2) United States, and (3) any country recruited through social media. Conjoint analyses were used to quantify the influence of antimicrobial cost, method of administration and drug importance in human medicine. Descriptive statistics were used for data evaluation. A total of 809 surveys were completed (US participants, n = 315; Canadian participants, n = 298; social media group, n = 196). Conjoint analysis results quantification revealed antimicrobial cost as accounting for 47% of dog‐owner preferences, followed by method of administration (31%) and drug importance (22%). All groups preferred drugs that cost $25 and were administered once by injection. US and Canadian participants were more likely to prefer drugs considered “very important” in human medicine, whereas social media recruited participants were more likely to prefer drugs that were “not at all important.” Most respondents (86%) reported AMR as important in human medicine and 29% believed pet antimicrobial use posed a risk for humans. Our research reveals cost as most important in dog‐owner antimicrobial preferences and provides practical information for antimicrobial stewardship initiatives. ABSTRACT ID08 Serum 25‐hydroxyvitamin D and canine infectious respiratory disease complex in shelter dogs Andrew Sun 1; Cody Blakeman1; Jared Jaffey1; Nancy Bradley‐Siemens1 ; Michael Lappin2; Jennifer Hawley2; Randy Ringold3; Rachael Kreisler1 1College of Veterinary Medicine, Midwestern University; 2College of Veterinary Medicine, Colorado State University; 3VDI Laboratory The background is as follows. Hypovitaminosis D is associated with increased susceptibility to acute respiratory infections and repletion decreases this risk as well as severity of illness in humans. Canine infectious respiratory disease complex (CIRDC) is common in animal shelters. These respiratory infections negatively impact dogs and consumes a substantial amount of shelter resources. The role of vitamin D in shelter dogs with CIRDC is unknown. Objectives are as follows. (1) Compare serum 25‐hydroxy (OH)‐vitamin D concentrations between shelter dogs with respiratory signs associated with CIRDC and shelter dogs without respiratory signs. (2) compare serum 25(OH)D concentrations between shelter dogs polymerase chain reaction (PCR) positive for Bordetella bronchiseptica (BB), Mycoplasma cynos (MC), canine herpesvirus‐1 (CHV‐1), and canine distemper virus (CDV). The methods are as follows. Serum 25(OH)D concentrations were measured with a commercially available chemiluminescent immunoassay kit and nucleic acids of common CIRDC agents were amplified by use of a commercially available service (Antech Diagnostics). Samples were obtained from left‐over blood samples taken by a shelter during a CIRDC outbreak. Unpaired two‐tailed t‐tests were used to compare square root transformed 25(OH)D concentrations with values reported back transformed and p < 0.05 considered significant. The results are as follows. One hundred and forty‐six shelter dogs were included. The median length of stay prior to sampling was 46 days (IQR 28–73). Thirty‐six (25%) shelter dogs exhibited respiratory signs at the time of inclusion, while 51 (35%) were sampled after resolution of respiratory signs and 4 (3%) before signs. Five dogs did not have available PCR results. Forty‐seven (32%) of dogs were PCR positive for at least one pathogen with 32 (23%), 11 (8%), 6 (4%), and 1 (1%) positive for MC, BB, CHV‐1 and CDV, respectively. Only two dogs were positive for more than one pathogen. The mean 25(OH)D concentration for dogs with respiratory signs at the time of sampling was 59.3 ng/ml (SD 1.5), while it was 66.6 ng/ml (SD 1.4) for dogs without, which was significantly different, t(142) = 2.0317, p = 0.0440. Dogs that were CHV‐1 positive had significantly lower serum 25(OH)D concentrations with a mean of 50.6 ng/ml (SD 1.8) than dogs that were CHV‐1 negative which had a mean of 65.5 ng/ml (SD 1.4), t(137) = 1.9814, p = 0.0495). There was no difference for dogs positive for BB or MC and dogs negative for those pathogens, p = 0.82 and p = 0.47, respectively. The conclusions/clinical importance are as follows. These results suggest that vitamin D has a potential clinical role in shelter dogs, particularly those with viral infections, and provides a rationale for future studies to investigate if repletion of vitamin D can decrease the prevalence, morbidity, or both of CIRDC in shelter dogs. ABSTRACT ID09 Markers of inflammation and cytokine concentrations during experimental Babesia rossi infection of beagle dogs Brogan K. Atkinson 1; Andrew Leisewitz2; Varaidzo Mukorera2; Peter Thompson2 1Onderstepoort Veterinary Academic Hospital, University of Pretoria; 2University of Pretoria Babesia rossi (B. rossi), the most virulent of canine Babesia parasites, causes severe clinical disease and death in dogs in sub‐Saharan Africa. Complications and multiple organ dysfunction seen with babesiosis are likely caused by the effects of an unfocused and excessive inflammatory response. The aim of this study was to investigate markers of inflammation and cytokine kinetics from the point of inoculation with B. rossi throughout the course of clinical disease and determine if infectious dose influenced rate and severity of disease progression. This experimental study was performed on 5 healthy sterilized male beagle dogs. Three dogs were given a high infectious dose and 2 dogs a low infectious dose of parasite. CBC, C‐reactive protein, albumin and lactate were determined daily. Cytokines were quantified on stored plasma using a canine specific cytokine magnetic bead panel (Milliplex©). Dogs were monitored daily until predetermined end points for treatment were reached. Post inoculation, initial parasitemia occurred on day 1 and day 3 in the high and low dose groups respectively. The rate of increase in parasitemia in the high dose group was significantly higher than seen in the low dose group. Significant differences between the high and low dose groups were found in body temperature, interferon gamma (INFγ), keratinocyte chemoattractant (KC), INFγ‐induced protein 10 (IP10), interleukin 8 (IL8), IL15, IL18, CRP, albumin, segmented and band neutrophils at certain time points. Significant differences were noted for pulse, glucose, lactate, granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), IFNγ, KC, IP10, IL2, IL6, IL7, IL8, IL10, monocyte chemoattractant protein 1 (MCP1), tumor necrosis factor alpha (TNFα), segmented neutrophils, band neutrophils, monocytes, CRP and albumin at certain time points within the high dose group and baseline. Significant difference was also noted for pulse, glucose, IFNγ, KC, IP10, IL8, segmented neutrophils, CRP and albumin between low dose group and baseline at certain time points. The majority of the variables evaluated were higher when comparing the high dose to low dose group and both groups to the baseline with the exception of albumin throughout the study and segmented neutrophils during infection, which were consistently lower. These findings suggest that in Babesia rossi infection, initiation of inflammation occurs before the onset of clinical disease and infectious dose affects the evolution of inflammation and the course and severity of disease. ABSTRACT ID10 Effect of probiotic containing Aspergillus‐derived ingredients on serum and urine galactomannan antigen assay in dogs Krystle L. Reagan 1; L. Joseph Wheat2; Jane Sykes1 1University of California, Davis; 2MiraVista Diagnostics The Platelia Aspergillus galactomannan antigen (GMA) enzyme‐linked sandwich immunoassay (ELISA) assay is used to support a diagnosis of systemic aspergillosis in dogs. In humans, false‐positive results are associated with administration of medications derived from molds. Several probiotic supplements contain fungal organisms or enzymes derived from molds that may cross‐react with the GMA ELISA. We sought to determine the effect of administration of an oral probiotic containing Aspergillus‐derived ingredients on serum and urine GMA levels in dogs by conducting a prospective, cross‐over study. Serum and urine galactomannan indices (GMI) were measured in 10 healthy dogs before (day 0), after 1 week (day 7) of probiotic administration, and 2 weeks after the probiotic was discontinued (day 21). Median (range) serum GMI were 0.19 (0.08–0.62), 0.22 (0.07–1.15) and 0.17 (0.14–0.63) at day 0, 7 and 21 respectively. Two of 10 dogs developed positive GMI (≥0.5) results after probiotic administration, and one dog initially had a positive GMI at day 0 that then returned to normal at days 7 and 21. No significant treatment effect was noted in the study period. Median (range) urine GMI results were 0.06 (0.04–0.22), 0.07 (0.05–0.41) and 0.06 (0.03–0.16) at day 0, 7 and 21 respectively. No positive urine GMIs were noted. Administration of a probiotic containing Aspergillus‐derived ingredients did not reliably result in elevated serum or urine GMA levels. Three dogs had low‐grade positive GMI, one at each study time point, that did not correlate to probiotic administration. ABSTRACT ID11 Feline parvovirus seroprevalence is high in cats from disease outbreak and non‐outbreak regions in Australia Elizabeth L. Jenkins 1; Conor Davis2; Maura Carrai2; Michael Ward2; Susan O'Keeffe3; Martine van Boeijen4; Louise Beveridge5; Costantina Desario6; Canio Buonavoglia6; Julia Beatty2; Nicola Decaro6; Vanessa Barrs2 1University Veterinary Teaching Hospital Sydney; 2Sydney School of Veterinary Science, University of Sydney; 3School of Veterinary and Lifesciences, Murdoch University; 4Perth Cat Hospital; 5Bedford‐Dianella Vet Centre; 6Department of Veterinary Medicine, University of Bari Multiple, epizootic outbreaks of feline panleukopenia (FPL) caused by feline parvovirus (FPV) were recorded in shelter‐housed and owned cats in eastern Australia between 2014 and 2018. Most affected cats were unvaccinated. We hypothesized that low population immunity was a major driver of re‐emergent FPL. The aim of this study was to (i) determine the prevalence and predictors of seroprotective titers to FPV among shelter‐housed and owned cats, and (ii) compare the prevalence of seroprotection between a region affected by FPL outbreaks (Sydney, eastern Australia), and a region with no recent history of FPL outbreaks (Perth, western Australia). FPV antibodies were detected by hemagglutination inhibition assay on sera from 523 cats and titers ≥1:40 were considered protective. Socioeconomic indices based on postcode and Australian Bureau of Statistics census data were included in the risk factor analysis. The overall prevalence of protective FPV antibody titers was 94.3% and was similar between cats from outbreak (94.3%) and non‐outbreak regions (94.2%). On multivariable logistic regression analysis vaccinated cats were 29.94 times more likely to have protective FPV titers than cats not known to be vaccinated. Cats from postcodes of relatively less socioeconomic disadvantage were 5.93 times more likely to have protective FPV titers. The predictors identified for FPV seroprotective titers indicate that support targeted vaccination strategies in regions of socioeconomic disadvantage would be beneficial to increase population immunity. The critical level of vaccine coverage required to prevent FPL outbreaks should be determined to support initiatives to prevent the reemergence of this frequently fatal disease. ABSTRACT ID12 point prevalence surveys to investigate a veterinary hospital outbreak of carbapenem Resistant Escherichia coli Stephen Cole; Jaclyn Dietrich; Donna Oakley; Shelley Rankin University of Pennsylvania Reports of Carbapenem‐resistant Enterobacteriaceae (CRE) are limited to sporadic cases in animals and there is therefore, a lack of outbreak investigation guidelines for veterinary facilities. As these organisms continue to emerge in veterinary medicine it is critical to evaluate the utility of outbreak investigation strategies. The CDC Facility Guidance for Control of Carbapenem‐resistant Organisms suggests that serial point prevalence surveys (PPS) are useful to document ongoing transmission in healthcare facilities. In May 2019, the clinical microbiology lab at Matthew J. Ryan Veterinary Hospital at the University of Pennsylvania (MJR‐VHUP) reported a cluster of NDM‐5 producing Escherichia coli isolated from 15 animals to the Philadelphia Department of Public Health (PDPH). This represented the first report of a CRE outbreak in a US veterinary facility. The PDPH recommended a weekly PPS and due to lack of IACUC approval for the collection of rectal swabs this was performed using free‐catch fecal samples for two weeks. Following review by a clinical ethicist, rectal swabs were collected from all hospitalized animals on the day of testing for the next 9 weeks. Specimens were screened using chromogenic agar. The production of carbapenemase was confirmed by mCIM. Epidemiologic data collected included; number of visits to MJR‐VHUP and days hospitalized prior to sampling. PPS's were performed on fecal specimens from 16 of 21 animals and 14 of 22 animals in weeks one and two. All tested negative. Review of the protocol by a clinical ethicist stated that “if [PDPH] determine[d] that testing [was] necessary for all hospitalized patients…rectal swabs should be obtained…because it is imperative that sampling be thorough and expedient.” Rectal swabs or fecal samples were obtained from 268 patients over 11 weeks. Fourteen animals (13 dogs and 1 cat) tested positive (5.2%). The average number of visits for positive patients was 10 (vs. 6 for negative) and the average number of days hospitalized prior to sampling was 5 (vs. 2 for negative). Two patients tested negative and then positive in a second PPS. Half (n = 7) of the colonized patients were on their first visit to MJR‐VHUP and 4/7 were hospitalized less than 48 hours prior to sampling. An important “lesson learned” is that all veterinary facilities should have policies in place to sample animals as part of a public health response. The PPS was a useful tool to document in‐facility transmission for two cases, but positive animals detected within 48 hours of admission suggested a potential community source and dictated the need, in this outbreak, for admission and discharge testing. ABSTRACT ID13 Pilot pharmacodynamic and safety study of canine‐parvovirus‐neutralizing‐antibody (KIND‐030a and KIND‐030b) in purpose bred puppies Ellen R. Ratcliff 1; Laurie Larson2; Allyson Avenatti1; Stephanie Pierce1; Tianhua Hu1; Melinda Poole1 1Kindred Biosciences, Inc.; 2School of Veterinary Medicine, University of Wisconsin‐Madison The purpose of this proof‐of‐concept study was to determine the onset of detection, half‐life, safety, and bioavailability of canine parvovirus neutralizing antibody (KIND‐030a and KIND‐030b). Both are chimeric, high‐affinity monoclonal antibodies targeting canine parvovirus (CPV). Six unvaccinated, purpose‐bred, female beagle puppies, 10 to 12 weeks of age, with negative CPV titers on Day 0 were randomized 1:1 to a single dose of 5 mg/kg of either KIND‐030a (n = 3) or KIND‐030b (n = 3). A monovalent CPV vaccine was initially administered when the CPV hemagglutination inhibition (HI) titer dropped to 80 or lower as in vivo proof of viral neutralization and administered at least 2 more times. CPV HI titers on Day 0 were <20 prior to dosing in all 6 puppies and increased to greater than or equal to 2560 on Day 1 after KIND‐030 administration. The half‐lives of KIND‐030a and KIND‐030b were 10.1 days and 8.6 days, respectively. This half‐life roughly matches maternally derived antibody. The duration of immunity, defined as the duration in which the HI titer was maintained at 80 or higher, ranged from 30 to 42 days after one dose of either KIND‐030a or KIND‐030b. The virus neutralization (VN) results mirrored the HI results. The initial CPV vaccination did not result in seroconversion in 5 out of 6 puppies, potentially due to residual KIND‐030 antibodies neutralizing the vaccine. Blocking of vaccinal virus replication by both KIND‐030a or KIND‐030b was the first in vivo correlation to the in vitro neutralization data. Subsequently, three puppies seroconverted after the 2nd and one after the 3rd vaccination. The study was terminated on Day 100. In this proof‐of‐concept study, both KIND‐030a and KIND‐030b resulted in high titers, were well tolerated in puppies and no adverse events or injection site reactions were reported. This product is under clinical investigation and has not received approval by the USDA. ABSTRACT ID14 Using big data to investigate feline intestinal parasitism by geographic region and age Sarah L. Sweet 1; Evan Hegarty2; Donald McCrann2 1IDEXX Inc.; 2IDEXX Reference Laboratories Intestinal parasite risk to pet cats is underrepresented in the literature and is often overlooked by pet owners and veterinarians. The purpose of this study is to examine the risk of intestinal parasitism in cats by presenting the percentage of positive results for fecal samples tested using zinc sulfate flotation by centrifugation and Fecal Dx® Antigen Panel, as well as combined positive results from both methods. A retrospective sample of 89,379 test results conducted using both testing techniques was gathered from IDEXX Reference Laboratory data from the continental United States (U.S.) in 2017 and 2018. Percentages of samples that tested positive were calculated according to testing‐method, age, and region for roundworm, hookworm, and whipworm.* Percentages of positive test results are presented in Table 1. Roundworm was the most common intestinal parasite of cats in this study, while hookworm and whipworm were not commonly seen in these cats. This study reinforces the need for regular testing in younger cats, as cats less than 1 year of age were nearly five times more likely to be parasitized than cats 1 year of age or older when using flotation and antigen techniques combined. All U.S. geographic regions besides the West had notable percentages of positive test results, with approximately 1 in 20 cats testing positive for roundworm, hookworm, or whipworm. The percentage of samples that tested positive by antigen or by antigen in combination with flotation was appreciably higher than the percentage of samples that tested positive by flotation alone. This suggests that fecal antigen testing may be a more sensitive method for detection of these parasites, and the Companion Animal Parasite Council (CAPC) recommended combination of flotation with antigen testing may offer the greatest sensitivity. This study demonstrates that pet cats in the U.S. are at risk of intestinal parasitism and should receive regular fecal testing. *Hookworm: Ancylostoma tubaeforme, Ancylostoma braziliense, Uncinaria stenocephala; Roundworm (Ascarid): Toxocara cati, Toxascaris leonine; Whipworm: Trichuris serrata (formerly Trichuris felis).   ABSTRACT ID15 Pilot study to determine whether Cytauxzoon felis has expanded into Colorado Pierce Chan 1; Michael Lappin1; Jennifer Hawley2 1Veterinary Teaching Hospital, Colorado State University; 2Center for Companion Animal Studies Cytauxzoon felis is a piroplasm that infects both domestic and wild felids, with bobcats being the definitive host. Amblyomma americanum is considered the most important vector of C. felis and confirmed cases of cytauxzoonosis in cats overlaps with the distribution of A. americanum. The historical range of Amblyomma ticks includes the south central and southeastern US, but recent data has shown that the range has been expanding. Therefore, cases could be missed due to historical low prevalence. The purpose of this study was to use a PCR assay to amplify C. felis DNA in the blood of cats with suspected infectious hemolytic anemia in Colorado. Remnant whole blood DNA samples previously tested through the CSU Diagnostic Laboratory were stored at −80°C until assayed in this study. Submissions were searched from June 2004 to December 2018 for cats in which an infectious cause of anemia was suspected. Only samples from cats living in Colorado with adequate DNA were assayed. A previously published quantitative PCR assay that co‐amplifies the DNA of C. felis and Babesia spp. mitochondrial DNA was used for this study. Other PCR assay results that were previously performed for Bartonella spp. (29/98 samples) and Ehrlichia spp. (23/98 samples) were included in the analysis for this study. Samples were also tested for hemoplasmas (Mycoplasma hemofelis/M. turicensis and M. haemominutum) if not previously performed. Overall, DNA of an infectious agent was amplified from 13/98 (13.2%) samples. Bartonella spp. DNA was amplified from 1/29 (3.4%) samples and hemoplasma spp. DNA was amplified from 12/97 (12.3%) cats. Babesia spp., Ehrlichia spp., and C. felis DNA were not amplified in any sample. Cytauxzoon felis DNA was not amplified in any sample, although 13% of samples tested positive for an infectious agent. The results of this pilot study show no evidence that the range of C. felis has expanded to include Colorado. ABSTRACT ID16 Prevalence of Ehrlichia canis antibodies in dogs in Baja Sur, Mexico Michael R. Lappin 1; Cody Minor2; Arianne Morris1; Melissa Brewer1; Jennifer Hawley1; Amy Rex3 1Colorado State University; 2Unknown; 3Vet Clinic Rhiphicephalus sanguineous is the most common tick in Baja Sur, Mexico and is known to be a vector for multiple pathogens including Ehrlichia canis, Babesia vogeli, Anaplasma platys, and Rickettsia rickettsii. The objectives of this study were to determine the prevalence of E. canis antibodies in dogs not currently treated with an acaracide and those provided a collar with 10% imidacloprid +4.5% flumethrin (Seresto®; Bayer Animal Health) and tested again 180 days later. The study was performed in the Todos Santos area over two, 180‐day periods. Owners were offered free testing for tick borne agents as well as flea and tick control products. A subset of owners with dogs that were negative for E. canis antibodies (IFA <1:80 or SNAP4DX Plus negative) and negative for E. canis DNA by PCR assay were given a collar and offered a financial incentive to return for recheck examinations and testing. Dogs with lost collars replaced within 7 days remained in the study. Ehrlichia canis antibodies were detected in 64.8% (79 of 122) and 43.2% (121 of 280) of the dogs on Day 0 of Period 1 and Period 2, respectively. Nineteen negative dogs in Period 1 and 60 negative dogs in Period 2 returned for all rechecks. Of these 79 dogs, three had E. canis antibodies (2 concurrently PCR positive) in the 180‐day samples. For 2 dogs, the collar was missing for greater than 7 days and for one dog, the owner stated that the collar had been lost but was unsure whether it was replaced within 7 days. Antibodies against E. canis are common in dogs that are not treated with acaracides in this region of Mexico. ABSTRACT ID19 Etiology and seasonality of fecal enteropathogens from diarrheic cats: A retrospective study of 1620 cases Ye‐In Oh 1; Kyoung‐Won Seo2; Sung‐Soo Kim1; Sanghyuk Seo1; Jaegon Ah1; Do‐Hyung Kim3; Doo‐Sung Cheon4 1VIP Animal Medical Center, Chungnam National University; 2Chungnam National University; 3Knotus Inc.; 4Postbio Inc. Diarrhea is one of the most common clinical symptoms encountered in cats and can be caused by infectious pathogens. In this retrospective study, we aimed to identify the etiology, clinical features, and seasonality of enteropathogens in diarrheic cats using quantitative polymerase chain reaction (qPCR). Comprehensive diarrheal qPCR panels were performed on fecal samples from 1620 cats with diarrhea in Republic of Korea from April 2016 to April 2019. Among 1620 diarrheic cats, the positive infection rate was 82.59%. Bacterial, viral, and protozoal infections accounted for 49.3%, 37.57%, and 13.13% of cases, respectively. Feline enteric coronavirus (FECV) was the most common pathogen (29.37%), followed by Clostridium (C.) perfringens, Campylobacter (C.) coli, feline parvovirus, and Tritrichomonas foetus. The seasonality of enteropathogens was observed with peaks as follows: bacterial infections peaked in October, viral infections peaked in November, and protozoal infections peaked in August. Viral and protozoal infections showed differences in prevalence according to patient age. Investigation of infection patterns revealed that the ratios of single infections, mixed infections, and co‐infections were 35.72%, 9.87%, and 54.41%, respectively. FECV was predominant in single infections. The most common infection patterns were a combination of C. perfringens and C. coli in mixed infections and a combination of C. perfringens and FECV in co‐infections. Infection patterns differed according to the enteropathogen species, seasonality, and age distribution in cats. The results of this study could be helpful in the diagnosis, treatment, and prevention of spreading infection in feline infectious diarrhea. In addition, continued monitoring of feline enteropathogens is required. ABSTRACT ID20 Vaccination history in dogs with acute respiratory disease suspected to be associated with parainfluenza virus Cindy Sotelo 1; Michael Lappin2; Ashley Gange3; Tracey Jensen3 1Colorado State University; 2Internal Medicine Service, VTH, Colorado State University; 3Wellington Veterinary Hospital Parainfluenza virus is a cause of the canine infectious respiratory disease complex (CIRDC) and vaccines containing the virus are available for parenteral or intranasal administration. Parenteral parainfluenza containing vaccines are frequently recommended every 3 years after the initial vaccination series since it is usually combined with canine distemper virus and canine parvovirus which induce long term sterilizing immunity. A group of dogs were evaluated in a clinic in North central Colorado for acute clinical signs of disease consistent with CIRDC. Each dog had samples evaluated at commercial laboratories for nucleic acids of the common bacterial and viral agents associated with CIRDC. The 19 dogs were all sampled between December 20, 2018 and January 8, 2019 and were all suspected to be involved in the same CIRDC outbreak. Nucleic acid amplification rates for Mycoplasma spp., parainfluenza, Bordetella bronchiseptica, and adenovirus were 84%, 52%, 21%, and 5%, respectively. Of the 10 dogs with parainfluenza virus RNA, 90% were also positive for nucleic acids of Mycoplasma (8 dogs), B. bronchiseptica (2 dogs), or adenovirus (1 dog). All of the dogs positive for parainfluenza RNA had been administered an oral B. bronchiseptica vaccine with the time since the last dose ranging from 1.5 weeks to 23 months. Of the 10 dogs positive for parainfluenza virus RNA, the time since administration of the last parenteral vaccine containing this virus ranged from 16 months to 7 years. The patient that had parainfluenza RNA isolated on swab with no other pathogen isolated received parainfluenza vaccination (along with distemper and parvo) 1 year and 4 months prior to the respiratory panel. Parainfluenza virus was suspected as the cause of this CIRDC outbreak since none of the dogs had been recently vaccinated with products containing this virus to explain the positive molecular assay results and there was one patient positive for parainfluenza virus RNA alone. If this hypothesis is correct, it suggests that use of parenteral parainfluenza vaccines at an interval at greater than 16 months may not provide complete protection. ABSTRACT ID21 The role of Streptococcus equi subspecies Zooepidemicus and influenza viruses in URIs in shelter cats Anna Winner; Hayley Clark; Jennifer Hawley; Michael Lappin College of Veterinary Medicine and Biomedical Sciences, Colorado State University Feline respiratory disease complex (FRDC) is characterized by clinical signs of respiratory and/or ocular disease in susceptible cats and is a prevalent problem in overcrowded settings like animal shelters. Included in the complex are a variety of pathogens, particularly feline herpesvirus‐1 (FHV‐1), feline caliciviruses (FCV), Bordetella brochiseptica, Mycoplasma spp., and Chlamydia felis. Recently, a number of cats have been shown to be infected by influenza A viruses or Streptococcus equi subspecies zooepidemicus, but little is known about the incidence of these potential pathogens in cats in shelters in Colorado. This study aims to determine the estimated prevalence rates for influenza A viruses and S. zooepidemicus to determine whether these are additional major contributing pathogens to FRDC. All cats in the study were housed in shelters in north‐central Colorado and had acute clinical signs of FRDC. Archived DNA and RNA extracts (stored at −80°C) from 2008 (52 cats) and prospective samples collected from 24 cats in 2019 were included. All samples were assayed for nucleic acids of influenza A viruses and for S. zooepidemicus. In the experiment completed in 2019, while none of the samples from the 21 cats were positive for RNA of influenza viruses or DNA of S. zooepidemicus, nucleic acids of C. felis (4.2%), FHV‐1 (8.3%), Mycoplasma spp. (20.8%), or FCV (37.5%) were amplified from many cats. In the experiment completed in 2008, while none of the samples from the cats tested were positive for RNA of influenza viruses, DNA of S. zooepidemicus, or C. felis, nucleic acids of FCV (2.1%), Mycoplasma spp. (58.1%), or FHV‐1 (74%) were amplified from many cats. Both single and co‐infections were detected in both sample sets. While influenza virus and S. zooepidemicus infections have been detected in dogs in the shelters used in this study, the infections did not appear to be associated with clinically ill cats during the study periods. ABSTRACT ID22 Evaluation of the clinical performance of a point‐of‐care Coccidioides antibody tests in dogs Krystle L. Reagan; Ian McHardy; George Thompson; Jane Sykes University of California, Davis Point‐of‐care (POC) Coccidioides antibody assays may provide veterinarians with a more rapid, patient‐side diagnosis when compared with the serologic reference standard, immunodiffusion. The objective of this study was to determine the sensitivity and specificity of a POC lateral flow assay (LFA), sona Coccidioides (IMMY, Norman, OK), using the immunodiffusion assay (Coccidioidomycosis Serology Laboratory, University of California, Davis, CA) as the reference standard. Sera specimens were collected from client‐owned dogs both prospectively and from stored specimens. Animals were classified as Coccidioides antibody positive (CP, n = 36) based on a positive quantitative IgG immunodiffusion. Animals were Coccidioides antibody negative (CN, n = 12) based on a negative immunodiffusion test. The sensitivity and specificity of the POC assay were calculated by comparing LFA results to the reference standard results. The sona Coccidioides antibody LFA assay correctly classified 32/36 CP specimens and 12/12 CN specimens resulting in a sensitivity of 88.9% (CI; 74.7–95.6%) and specificity of 100% (CI; 75.8–100%) as compared to immunodiffusion. A receiver operator characteristic curve was constructed, and the area under the curve was calculated to be 0.944 (CI; 0.880–1.000). Four false negatives were observed, all of which had low quantitative IgG immunodiffusion titers of 1:4. This POC assay is an alternative and rapid diagnostic tool to the traditional immunodiffusion assay. False negatives were observed in dogs with low quantitative immunodiffusion titers, therefore confirmatory testing is recommended. ABSTRACT ID24 In vitro inhibitory effects of polyammonium bisulfate and nanosulfur against canine isolates of Pythium insidiosum Cara E. Martin; Stuart Walton; Domenico Santoro; Justin Shmalberg University of Florida College of Veterinary Medicine Pythium insidiosum, an aquatic oomycete, causes life‐threatening dermatologic and gastrointestinal disease in dogs. Infection is characterized by rapid clinical progression with a high mortality rate due to extensive, but typically localized, spread of disease. There is no consensus on standard treatment recommendations but complete surgical resection of affected tissues, where possible, and long‐term adjunctive antifungal therapy are commonly advised. Variable response to treatment has prompted the use of other compounds and combination protocols as alternative options for the management of Pythium insidiosum infections in animals. Polyammonium bisulfate molecular clusters (PBMS) and nanosulfur are new compounds successfully used in agriculture to treat algae, fungi, and bacterial infections in plants and water reservoirs which are theorized to exert effects on oomycetes. The primary aim of this study was to investigate the in vitro activity of PBMS and nanosulfur against clinical isolates of Pythium insidiosum acquired from canine patients. Four isolates of Pythium insidiosum were obtained from cultures of infected canine tissue. Each isolate was incubated for 24 hours at 37°C in triplicate on 20% clarified v8 agar with and without antimicrobials (nanosulfur and PBMS). Three two‐fold dilution of antimicrobials (nanosulfur and PBMS) were added to the agar immediately before plating. Nanosulfur was used at concentrations of 500, 1,000, and 2,000 μg/mL. Three solutions of PBMS containing 5% copper, 9.8% zinc, and 5% zinc with 2.5% copper were used at concentrations between 0.25 to 5 μg/mL of Cu and 0.5 to 9.8 μg/mL of Zn. Isolates not exposed to antimicrobials served as positive controls. After 24 hours, each isolate was re‐implanted onto new plates to simulate repeat dosing. Radial growth of the colony was recorded in mm at 24, 48, and 72 hours. Colony diameter was calculated as the mean of two perpendicular measurements with the diameter of the mycelial plug subtracted. The median of the triplicates was used for statistical analysis. Kruskal‐Wallis followed by the Dunn's multiple comparison test were performed. A p value of <0.05 was considered statistically significant. Colony growth was uniform among all the isolates. Compared to the positive control, PBMS (9.8% Zn) at 9.8 μg/mL significantly inhibited the growth after 48 hours (40.5% diameter reduction) and 72 hours (29.2% diameter reduction) (p = 0.005 and p = 0.02, respectively). Compared to the positive control, nanosulfur significantly inhibited the growth at 2,000 μg/mL after 72 hours (38.9% diameter reduction), at 1,000 μg/mL after 24 (43.8% diameter reduction) and 72 hours (38.9% diameter reduction), and at 500 μg/mL after 24 (46.9% diameter reduction), 48 (40.5% diameter reduction), and 72 hours (36.1% diameter reduction) (p < 0.05). Radial growth of Pythium isolates was significantly inhibited by all concentrations of nanosulfur tested and by 9.8 μg/mL of PBMS 9.8% Zn. Re‐implantation of isolates was designed to mimic more realistic circumstances in which antimicrobials would be administered repeatedly, assuming adequate absorption into infected tissue. Inhibition of growth appeared to be most pronounced at earlier time points. Results suggest that nanosulfur and PBMS with Zn may be promising adjunctive therapies for the treatment of Pythium insidiosum. Additional investigation is necessary to determine whether nanosulfur or PBMS 9.8% Zn improve growth inhibition when used in combination protocols with other previously‐studied agents such as mefenoxam, caspofungin, itraconazole, and terbinafine. ABSTRACT NU01 Urine‐specific gravity is less predictive than nutritional factors for management of urolithiasis in cats Jennifer M. MacLeay 1 ; Mikaleigh Woodward2; Stephen Davidson1; Kathy Gross1 1Hill's Pet Nutrition, Inc.; 2KSU Urolithiasis due to calcium oxalate (CaOx) or struvite (MAP) are common causes of lower urinary tract disease in cats. A common recommendation is to monitor urine‐specific gravity (USG) as a surrogate for relative supersaturation calculation (RSS) and calcium oxalate titration testing (COTT) as these tests are not commercially available. However, the refractometer is limited in sensitivity to small molecules that may have a profound impact on urine performance. In this study a meta‐analysis of 41, two or four week long monadic feeding tests was undertaken to determine the correlation between RSS MAP, RSS CaOx or COTT and USG. All methods were approved by an internal animal care and use committee. Tests encompassed 32 dry, 7 wet and 2 combined wet and dry foods. Each test was comprised of 10 or 12 healthy adult cats 1–11 years old. At the end of each test freely voided urine was collected over 24 hours using a closed system with inert litter box beads. Urine pH was measured using a calibrated meter and USG by refractometer. The COTT was performed by titrating whole urine with sodium oxalate until precipitation occurred according to the method described by Davidson et al. (JVIM 2015). RSS CaOx and MAP were calculated using EQUIL software from urinary concentrations of NH4 +, Ca+2, Cl−, citrate, creatinine, Mg+2, oxalate, PO4 −3, K+, Na+, SO4 −2 and urine pH. Correlation tests were performed using Proc Corr in SAS. Significant differences were set at p < 0.05. Across these 41 studies, age and USG were not correlated. RSS for MAP and CaOx were significantly correlated with USG but the r values were low (MAP r = 0.19, p < 0.0001 and CaOx r = 0.11, p = 0.02). COTT was not significantly correlated with USG (r = −0.04, p = 0.44). Across the entire data set, USG ranged from 1.016–1.084 and fold differences in urine analyte concentrations were broad; Ca 86x, Cl 31x, Mg 80x, P 35x, K 15x, Na 132x, oxalate 8x, Sulfate 15x, citrate 373x, pH 0.68x, and creatinine 6x. It was observed that minimum values for dry and wet foods were similar for USG, RSS MAP, RSS CaOx and COTT. Further, USG for the 7 wet formulas were not uniformly low (1.020, 1.027, 1.028, 1.035, 1.037, 1.044, 1.046) and lastly, 2 foods with different nutritional profiles were fed as both dry and wet forms and the wet forms had reduced USG (wet, dry food A 1.044, 1.061 and food B 1.020, 1.054), RSS CaOx and COTT but RSS MAP was similar. In conclusion, a meta‐analysis of 41 cat urinary studies showed that nutrition has a profound impact on the concentration of urine constituents and use of USG as a surrogate for RSS or COTT is not supported as dry foods can induce urine with low RSS and COTT. Practitioners must continue to rely upon information from manufacturers concerning how any food impacts urine mineral concentration, pH and, in turn, stability. However, a subset of this data suggests monitoring USG is most useful after instituting nutritional therapy with a food shown to reduce oxalate risk. ABSTRACT NU02 Voided urine collection methods for urine culture in female dogs with lower urinary tract signs Lynn Little 1; Michael Childress1; Ben Olson2; Audrey Ruple1; Sarah Steinbach1; Lynn Guptill1 1Purdue University; 2Pieper Memorial Cystocentesis is currently the only recommended collection method for urine culture in female dogs, presenting a diagnostic challenge in patients for which cystocentesis is contraindicated, such as transitional cell carcinoma or thrombocytopenia. We hypothesized that culture results of clean, midstream voided urine samples would predict culture results of samples obtained via cystocentesis or cystoscopy if quantitative interpretive cut‐offs were applied. Fifty‐three female dogs experiencing lower urinary tract signs were prospectively enrolled with informed client consent at Purdue University's Veterinary Teaching Hospital. All dogs had 3 urine samples collected and submitted for urine culture within 24 hours: standard mid‐stream voided (SMV), clean mid‐stream voided (CMV), and a sterile sample obtained by cystocentesis or cystoscopy (CC). One or more cultures were positive for bacterial growth in 37/53 (70%) patients, however, only 40% (21/53) of CC cultures were positive. Comparing CMV and CC samples, growth of the same organism(s) or no growth on either culture occurred in 64% of samples (34/53). Comparing SMV and CC samples, the same result occurred in only 27/53 (51%). When SMV and CMV samples with quantitative cultures (35/53) were assessed for significant bacteriuria (≥105 CFU/ml based on current guidelines), the CC sample result could be predicted from the SMV sample in 80% (28/35) of patients and the CMV sample in 83% (29/35). While sterile sampling methods remain the gold standard method for urine culture in female dogs, when interpretive cut‐offs are applied, voided samples may be an acceptable alternative in patients for which cystocentesis is contraindicated. ABSTRACT NU03 reticulocyte indices for the assessment of iron status in cats with chronic kidney disease Adeline Betting; Thierry Francey; Ariane Schweighauser Vetsuisse Faculty, University of Bern Gastrointestinal bleeding, erythropoietin therapy, and chronic hematuria can lead to iron deficiency (ID) in cats with chronic kidney disease (CKD), especially in those with subcutaneous ureteral bypasses (SUB). However, the assessment of the iron status is poorly defined in this species. The reticulocyte indices, reticulocyte hemoglobin content (CHr) and reticulocyte mean cell volume (MCVr), have been proposed to reflect the iron status of humans and dogs, but they have not been evaluated extensively in cats. The objective of this study was therefore to assess their diagnostic value for ID in cats with CKD with or without SUBs. Sixty‐two cats were prospectively enrolled (15 CKD, 31 SUB, 16 healthy controls). All cats were characterized with a physical examination, abdominal radiographs, blood and urinalysis, and a complete iron panel (total serum iron, ferritin, total iron binding capacity). The transferrin saturation (TSAT) was calculated and used to define ID as TSAT<20%. ID was diagnosed in 9/62 (15%) cats, including 3/15 (20%) cats with CKD, 5/31 (16%) cats with a SUB and 1/16 (6%) healthy cats; 11/62 (18%) cats were anemic. Median TSAT was 26.4% (range, 16.1–46.8%) in cats with CKD, 26.1% (10.0–41.3%) in cats with SUBs, and 28.1% (18.1–52.2%) in healthy cats. Cats with ID had a lower CHr (15.6 pg; interquartile range, 14.7–17.0) than cats without ID (17.7 pg; 16.6–18.7; p = 0.016), with a large overlap between the groups. The correlation between CHr and TSAT was moderate (r = 0.37). A ROC curve analysis yielded a moderate discriminatory value for CHr in the diagnosis of ID (AUC = 0.75; p = 0.006) and compared favorably to the currently available variables MCV (AUC = 0.58; p = 0.458) and MCHC (AUC = 0.71; p = 0.023). It was however a weaker predictor of ID than the total iron concentration (AUC = 0.97, p < 0.001). MCVr was not different between the groups (p = 0.226). Based on these results, CHr and MCVr do not seem to add diagnostic value to the currently available hematology variables in cats with CKD. Despite its limitations, total serum iron concentration was the best alternative to a complete iron panel in our study population. ABSTRACT NU04 association between hyperlipidemia and lower urinary tract calcium oxalate stones in dogs: Initial results Mathieu V. Paulin 1; Marilyn Dunn2; Catherine Vachon2; Bérénice Conversy2 1Faculty of Veterinary Medicine, University of Montreal, Canada; 2Montréal's Faculty of Veterinary Medicine in Saint‐Hyacinthe In people, obesity and metabolic syndrome have both been associated with formation of calcium oxalate stones (CaOxS). The goal of our study is to evaluate the association between obesity and hyperlipidemia (total cholesterol‐TC and triglycerides‐TG) and CaOxS formation in dogs. Dogs presenting for lower urinary tract stone removal with confirmed CaOxS (S‐dogs) were prospectively enrolled. Control dogs were deemed healthy based on blood work, urinalysis and imaging ruling out CaOxS (SF‐dogs). Body condition scores (BCS, 1–9 scoring scale), serum TC and TG levels were recorded. Statistical analyses included‐[A] or not‐[B] Schnauzers and comorbidities (Mann‐Whitney‐Wilcoxon and Fisher's exact tests). Seventy‐one S‐dogs and 33 SF‐dogs (76/36% of males, median ages 9/6.5 years old, median weights 10.5/7 kg, respectively) were included in the study. The S‐group was composed of Miniature Schnauzers (20%), Shih Tzus (17%), Yorkshire Terriers (14%) and 12 other breeds, and the SF‐group of 15 breeds without any Schnauzers. In the S‐group, comorbidities included hyperparathyroidism (3 dogs), hypothyroidism (2), hyperadrenocorticism (2), and diabetes mellitus (1). Calcium oxalate stones were primarily removed by minimally invasive procedures. Body condition score was significantly higher in S‐dogs than SF‐dogs (p = 0.02–[A]). Thirty‐eight percent [8/21] of hypertriglyceridemic S‐dogs were Schnauzers. Hypertriglyceridemia (>2.38 mmol/L) was significantly more frequent in S‐dogs (p = 0.0001–[A]; 20 versus 0%, p = 0.005–[B]). Median TC (p = 0.01–[A]; 6.5 versus 5.6 mmol/L, p = 0.03–[B]; Figure 1) and TG levels (p < 0.0001–[A]; 0.91 versus 0.49 mmol/L, p = 0.001‐[B]; Figure 2) were significantly higher in S‐dogs. Our study suggests that BCS and hyperlipidemia are significantly associated with lower urinary tract CaOxS in dogs.   ABSTRACT NU05 Predicting early risk of chronic kidney disease in dogs JoAnn Morrison 1; David Aucoin2; Richard Bradley3; Geert De Meyer3; James Kennedy4; Minseung Kim5; Yiannis Kokkinos5; Theodoros Panagiotakos5; Ilias Tagkopoulos5; Phil Watson3 1Banfield Pet Hospital; 2Antech Diagnostics; 3Waltham Petcare Science Institute; 4Mars Advanced Research Institute; 5PIPA LLC Study purpose: Advanced machine learning methods combined with large sets of health screening data provide opportunities for diagnostic value in human and veterinary medicine. The purpose of this study was to derive a model to predict the risk of dogs developing chronic kidney disease (CKD) using data from electronic health records (EHRs) collected during routine veterinary practices at primary care hospitals in the United States. Methods: A total of 55885 dogs that visited Banfield Pet Hospitals between February 1, 1996 and March 31, 2018 were included in the study. Longitudinal EHRs from Banfield Pet Hospitals were extracted and randomly split into 2 parts. The first 66% of the data were used to build a prediction model, which included feature selection and identification of the optimal neural network type and architecture. The remaining unseen EHRs were used to evaluate the model performance. Results: The final model was a recurrent neural network (RNN) with 6 features (creatinine, blood urea nitrogen, urine‐specific gravity, urine protein, weight and age). When predicting CKD near the point of diagnosis, the model displayed a sensitivity of 91.4% and a specificity of 97.2%. Model sensitivity decreased when predicting the risk of CKD with a longer horizon, having 69.2% sensitivity 1 year before diagnosis and 44.9% 2 years before diagnosis, but with specificity remaining around 97%. Conclusions reached: The use of models based on machine learning can support veterinary decision making by improving early identification of canine CKD. Considering the prognosis of CKD in canines, earlier identification could allow for greater opportunities for interventions and positive impacts on prognosis and patient outcomes. ABSTRACT NU06 Alterations of serum amino acid profiles in cats with chronic kidney disease Stacie Summers 1; Amanda Blake2; Jessica Quimby3; Jonathan Lidbury2; Joerg Steiner2; Jan Suchodolski2 1Oregon State University; 2Texas A&M Gastroenterology Lab; 3The Ohio State University Chronic kidney disease (CKD) is common in senior cats and is associated with dysrexia, weight loss, cachexia, and accumulation of harmful metabolites of protein fermentation by colonic bacteria. Amino acid derangements may be a therapeutic target in CKD cats to reduce loss of muscle mass. The objective of our study was to measure serum amino acid concentrations in cats with CKD and compare results to healthy senior cats. Serum was collected from healthy senior cats (≥8 years; n = 16) and CKD cats (International Renal Interest Society (IRIS) stage 1, n = 2; stage 2, n = 9; stage 3, n = 11; stage 4, n = 4). After deproteinization and filtration, the serum was analyzed on a Biochrom 30+ Amino Acid Analyzer to obtain concentrations of amino acids and other nitrogenous compounds. Unpaired student t test or Mann‐Whitney test was used to compare amino acid concentrations between two study groups. A Spearman rank was used to assess correlation between serum amino acid and creatinine concentrations. Cats with CKD had significantly decreased concentrations of the essential amino acids leucine (p = 0.010), methionine (p = 0.014), phenylalanine (p = 0.004), threonine (p = 0.003), tryptophan (p = 0.002), and valine (p = 0.040), and the nonessential amino acids serine (p = 0.031), tyrosine (p = 0.001), proline (p = 0.005), and asparagine (p = 0.046) when compared to healthy senior cats. The essential amino acid taurine (p = 0.002) and the nonessential amino acids citrulline (p = 0.002) and aspartic acid (p = 0.037) were increased in CKD cats when compared to senior cats. 3‐methylhistidine, an indicator of skeletal muscle protein breakdown, was significantly increased in CKD cats (p < 0.0001) when compared to senior cats and was positively correlated with serum creatinine (p < 0.0001; ρ = 0.858). In conclusion, the serum amino acid profile is altered in cats with CKD. 3‐methylhistidine may be a biomarker of skeletal muscle protein breakdown in CKD cats but since the amino acid is excreted by the kidneys further evaluation is needed. ABSTRACT NU07 Feline ureteral obstruction: A case‐control study of risk factors (2016–2019) Alex Kennedy; Joanna White Small Animal Specialist Hospital, Sydney Ureteral obstruction (UO) in cats causes acute kidney injury and typically requires surgical intervention. Further information is required about potentially modifiable risk factors to inform prevention strategies. A case‐control study was performed to assess risk factors associated with feline UO. Cases were defined as cats with i) ureteral obstruction confirmed with pyelography or ii) a creatinine concentration > 140 mcg/ml with both ureteral obstruction and pyelectasia ≥5 mm on abdominal ultrasound. Controls were defined as cats without evidence of ureteral obstruction on history, physical examination and abdominal ultrasound. Age, sex, breed (domestic or pedigree), diet (predominantly dry, mixed or predominantly wet food), housing (indoors or mixed) and total calcium were evaluated for their association with for UO using multivariable logistic regression. A receiver operator characteristics (ROC) curve was created to evaluate the predictive ability of the final model. One hundred and sixty‐eight cats (28 cases, 140 controls) were included. Neither age, sex, total calcium, breed nor housing were significantly associated with UO (Table 1). Diet was significantly associated with UO. Compared to cats eating a predominantly wet food diet, cats fed a predominantly dry food diet were 15.9 times more likely to develop a UO (confidence interval 2.9–295, p = 0.009). There was no difference in the association between diet and UO in cats fed a mixed diet compared to cats fed a predominantly wet food diet (p = 0.25). The area under the curve of the ROC curve was 72%. While the study is limited by the accuracy of owner recollection of diet, changes in dietary formulation could provide a simple and economical method to reduce the risk of UO. Table 1. 168 cats (28 ureteral obstruction and 140 controls): demographic data and results from bivariate logistic regression Ureteral obstruction No ureteral obstruction Coefficient (SE) p value Odds ratio (CI) Age (years) median (Q1–Q3) 5.75–10.875 5.000–13.000 −0.733 0.46375 ‐ Sex (number of cats) male: female 13:15 61:79 −0.278 0.781 ‐ Breed (number of cats) pedigree: domestic 13:15 63:77 0.139 0.89 ‐ Housing (number of cats) indoor only: indoor/outdoor 16:10 86:49 0.21 0.834 ‐ Diet (number of cats) mainly wet: mixed: mainly dry 1:10:17 28:82:30 2.603 0.00925 15.87 Total calcium (mmol/L) median (Q1–Q3) 2.212–2.284 2.09–2.4 0.812 0.417 ‐ CI = confidence interval. OR = odds ratio.   4 5 ABSTRACT NU08 The probability of persistence of an increased SDMA in cats and dogs Rebekah Mack‐Gertig ; Evan Hegarty; Donald McCrann IDEXX Symmetric dimethylarginine (SDMA) has been shown to be a sensitive and early marker of decreased glomerular filtration rate (GFR); however, some practitioners are uncertain how to interpret mild increases in SDMA concentrations above the reference interval (RI) as these may be perceived as inconsequential. The goal of this retrospective study was to assess the probability that an increased IDEXX SDMA® (>14 μg/dL) will be persistent, i.e., above the RI on follow‐up testing. Chemistry panel results from 1,578,808 cats and 3,643,452 dogs were collected from a 2‐year period beginning in July 2015. To meet inclusion criteria, animals were required to have a minimum of 3 chemistry results: the first with an SDMA concentration within the RI (0–14 μg/dL), followed by a second result with increased SDMA concentration, followed by a third SDMA result within 14 days to 18 months. In the 16,670 cats and 16,712 dogs that met these criteria, 53% of cats and 42% of dogs with mildly increased SDMA concentrations (15–19 μg/dL) on their second result were found to have increased SDMA concentrations on the third result. For comparison, the results of 45,169 cats and 117,225 dogs in which the first two results had SDMA concentrations within the RI were examined. The probabilities of a third result above the RI were found to be 14% in cats and 7% in dogs, markedly lower than those with increased SDMA results. This suggests that even a mildly increased SDMA infers 4 to 6 times the probability of an increased test on follow‐up compared to test results within the reference interval. With higher SDMA concentrations on the second result, higher persistence probabilities were noted: SDMA was increased on the third result in 76% of cats and 75% of dogs when SDMA concentrations were 20–24 μg/dL and 85% of cats and 82% of dogs when SDMA concentrations were 25+ μg/dL. This study demonstrates that patients with a mild increase in SDMA had a much higher probability of being above the RI on follow‐up testing than those with SDMA concentrations within the RI on second result, and that with higher SDMA concentrations there is a greater probability of persistence. These data suggest that even a mildly increased SDMA result is a sign of ongoing GFR impairment, indicating the need for appropriate follow‐up testing of SDMA and other renal biomarkers. ABSTRACT NU09 Association between ultrasound and renal biopsy features in dogs with protein‐losing nephropathy Lucy Kopecny; Carrie Palm; Kelsey Brust; Michelle Giuffrida; Larry Cowgill; Eric Johnson University of California, Davis Advances in categorization of canine glomerular disease have occurred with comprehensive pathologic evaluation, however, corresponding ultrasonographic features are not known. This study described ultrasonographic features in dogs with protein‐losing nephropathy (PLN) and evaluated associations between ultrasonographic and renal biopsy findings. Dogs with PLN undergoing renal biopsy with evaluation by light, electron and immunofluorescence microscopy from 2008–2018 were included. Medical records and renal biopsy reports were reviewed. Archived ultrasound images obtained within 30 days of biopsy were reviewed by two radiologists. Descriptive statistics were calculated. Continuous variables were assessed for normality. Ultrasound variables were compared using Fisher's exact or Wilcoxon rank sum tests. p < 0.05 was statistically significant. Seventy dogs were included. At biopsy, median creatinine, BUN, albumin and urine‐protein‐to‐creatinine ratio were 3.4 mg/dL (range, 0.5–15.2; reference range [RR] 0.8–1.5), 75 mg/dL (range, 7–245; RR 11–33), 2.4 g/dL (range, 1.0–3.8; RR 3.4–4.3) and 11.2 (range, 0.4–79.3; RR < 0.2), respectively. Morphologic diagnoses included membranoproliferative glomerulonephritis (n = 19), focal segmental glomerulosclerosis (n = 19), amyloidosis (n = 13), membranous glomerulopathy (n = 12), mesangioproliferative glomerulonephritis (n = 4), mixed glomerular disease (n = 3) and end‐stage renal disease (n = 2). Histopathologic abnormalities within the tubulointerstitial space were associated with increased cortical echogenicity (p = 0.008). Gastric wall thickness >5 mm was associated with histopathologic diagnosis of acute, versus chronic disease (p = 0.004). No significant associations were detected between: a) immune and non‐immune‐mediated glomerulopathy, b) acute and chronic disease or c) presence and absence of tubulointerstitial disease regarding corticomedullary ratio, medullary echogenicity or abdominal fluid. These findings suggest ultrasonographic features are poorly associated with specific pathologic patterns in canine PLN. ABSTRACT NU10 Comparison of dipstick salivary and blood urea nitrogen measurement to diagnose azotemia in dogs J.D. Foster Friendship Hospital for Animals Rapid detection of azotemia may be very helpful in emergency situations. Dipstick measurement of blood urea nitrogen (BUN) has been previously shown to have 85–95% sensitivity in identifying azotemia in dogs. Salivary urea nitrogen concentration correlates well with serum urea nitrogen, suggesting dipstick salivary urea nitrogen measurement may be an acceptable method of identifying azotemia. Dogs were prospectively enrolled to receive concurrent saliva and whole blood urea nitrogen dipstick measurement, stratified into four categories based upon the reagent area color change. Measurements were compared to serum BUN measurement via a dry chemistry machine. Azotemia was defined as BUN > 30 mg/dL measured by the reference method. The rate of correct classification and sensitivity, specificity, and predictive values for predicting azotemia were calculated for dipstick methods. 126 dogs were enrolled in this study, 38 (30%) dogs were azotemic. Saliva and blood dipstick testing correctly classified 44% and 56% of dogs, respectively, into the appropriate category. Saliva dipstick results within categories 3 or 4 (BUN > 30 mg/dL) was 81.6% sensitive, 69.3% specific, and had a 53.5% positive predictive value and 89.7% negative predictive value for identifying azotemia. Blood dipstick results within categories 3 or 4 was 94.7% sensitive, 78.4% specific, and had a 65.6% positive predictive value and 97.2% negative predictive value for identifying azotemia. Both blood and saliva dipstick measurements had poor accuracy in determining serum BUN. Blood dipstick measurement had better performance than saliva. Saliva dipstick testing may be best used to exclude azotemia if results are within category 1 or 2.   ABSTRACT NU11 Agreement of renal biomarkers: longitudinal evaluations of increased SDMA and creatinine in cats and dogs Rebekah Mack‐Gertig ; Evan Hegarty; Donald McCrann IDEXX Symmetric dimethylarginine (SDMA) and creatinine (Cr) are commonly used renal biomarkers. Previous studies have supported SDMA as an earlier and more sensitive indicator of decreased glomerular filtration rate (GFR) than Cr. However, in practice it may be difficult to see how often an increased SDMA is the first sign of impaired renal function. This retrospective study aimed to assess this by addressing the question: when SDMA is increased, how often is Cr increased on the same chemistry or within 1 year of the increased SDMA? And how do these compare to the same statistics for increased Cr? Chemistry panel results from 2,208,408 cats and 5,085,278 dogs were collected from a 2‐year enrollment period beginning in July 2015. For inclusion, animals were required to have a chemistry with IDEXX SDMA® and Cr results both below their upper reference limits (SDMA: ≤14 μg/dL, Cr: cats ≤2.3 mg/dL, dogs ≤1.5 mg/dL). Following this chemistry, animals were included in either the SDMA cohort and/or the Cr cohort if they had two sequential increased SDMA result s (>14 μg/dL) or two sequential increased Cr result s (cats > 2.3 mg/dL, dogs > 1.5 mg/dL), respectively, between 14 days and 18 months apart. These and all subsequent chemistry results from up to 3.5 years of available data were used to determine expected percentage of agreement between markers using the Aalen Johansen estimator. For the SDMA cohort, agreement was also calculated by initial increased SDMA concentration grouped by severity. Of the initial population, 9,707 cats and 8,040 dogs were enrolled for the SDMA cohort, and 2,603 cats and 2,220 dogs were enrolled for the Cr cohort. Results are shown in Table 1. When SDMA was increased, 30% of cats and 28% of dogs had concurrently increased Cr, with Cr agreement increasing to 57% of cats and 54% of dogs by 1 year. For Cr, 75% of cats and 69% of dogs had concurrently increased SDMA, with SDMA agreement increasing to 93% of cats and 87% of dogs by 1 year. The greatest diagnostic utility was seen in patients with initial increased SDMA results in the 15–19 μg/dL range, which comprised a majority of cases in this study and were likely animals whose declining renal function was detected early. SDMA was the only indicator of renal decline in 80% of these cats and 82% of these dogs at presentation. This study supports that an increased SDMA is an early indicator of renal impairment and often precedes an increase in Cr.   ABSTRACT NU12 Changes in symmetric dimethylarginine and glomerular filtration rates in dogs receiving oral prednisone Jean‐Sebastien Palerme; Jonathan Mochel; Austin Viall; Shane Murphy; Jessica Ward Iowa State University Symmetric dimethylarginine (SDMA) is a renal biomarker that correlates well with glomerular filtration rates (GFR) in dogs with renal disease and is thought to be superior to other markers such as creatinine since it is less influenced by non‐renal factors such as muscle mass. However, since SDMA is a product of proteolysis, it is possible that in catabolic conditions, such as hypercortisolism, SDMA levels might be increased independently of GFR. This study tested the hypothesis that SDMA would correlate poorly with GFR in healthy dogs receiving various doses of exogenous glucocorticoids. Eight healthy purpose‐bred research beagles were studied. Dogs underwent 5 sequential 5‐day treatment periods with intervening 9‐day washout periods: control (no prednisone) and 4 prednisone treatments (0.5, 1, 2, 4 mg/kg/day q24h). Samples from days 1 and 5 of each treatment were submitted for minimum database, urine protein creatinine ratio, GFR by iohexol clearance, free and bound cortisol levels, and SDMA. While GFR increased significantly in dogs receiving 4 mg/kg/day prednisone (13.86 vs. 8.66 ml/kg/day; p = 0.039), creatinine, BUN, and SDMA did not differ from controls at any prednisone dose. Contrary to BUN and creatinine, SDMA did have a weak correlation with prednisone doses (r = −0.28, p = 0.040) and total cortisol concentrations (r = 0.31, p = 0.022). No significant correlation existed between GFR and any of the renal biomarkers. These results suggest that SDMA levels might be affected by exogenous glucocorticoids. ABSTRACT NU13 Evaluation of feline urine concentrations of amoxicillin and clavulanate Kate KuKanich 1 ; Butch KuKanich1 ; Kallie Woodruff1; Mark Papich2; Zackery Bieberly1; Joshuah Klutzke1; Ron Orchard1; Lucy Schermerhorn1 1Kansas State University; 2North Carolina State University The aim was to measure feline urine concentrations of amoxicillin and clavulanate after oral administration of amoxicillin‐clavulanate, and to suggest updated feline urine‐specific susceptibility testing breakpoints for oral amoxicillin and amoxicillin‐clavulanate. The Clinical and Laboratory Standards Institute (CLSI) uses a feline breakpoint based on plasma drug concentrations (≤0.25 μg/mL), but a canine urine‐specific breakpoint exists (≤8 μg/mL). Eleven healthy non‐azotemic research cats were administered three 62.5 mg doses of amoxicillin‐clavulanate orally every twelve hours. Following the third dose, urine was collected from litter pans or via cystocentesis (the last urine collection) over the next 28 hours, recording each urination time and volume. A minimum of 3 urine samples were collected per cat. Liquid chromatography with mass spectrometry determined the urine concentrations of amoxicillin and clavulanate. The mean half‐life of amoxicillin in urine was 1.8 hours, and the mean recovery was 29%. The mean urine amoxicillin concentrations were 929 μg/mL (0–6 h) and 491 μg/mL (6–12 h). Amoxicillin concentrations were >8 μg/mL in urine collected prior to 12 hours from 10/11 cats, and > 2 μg/mL in the remaining cat. Clavulanate was detected in all urine samples. This study documented that oral amoxicillin‐clavulanate produced urine amoxicillin concentrations above the wild‐type cutoff (8 μg/mL) for Escherichia coli in 10/11 non‐azotemic cats. Because urine‐specific susceptibility testing breakpoints can be determined using urine concentrations, this information should allow new CLSI feline uropathogen susceptibility breakpoints for amoxicillin and amoxicillin‐clavulanate in non‐azotemic cats, specifically increasing the urine breakpoint from ≤0.25 μg/mL to ≤8 μg/mL. ABSTRACT NU14 The clinical presentation and outcome using various treatment modalities in 11 dogs with proliferative urethritis Max Emanuel 1; Taryn Donovan1; Ken Lamb2; Allyson Berent1; Chick Weisse1 1Animal Medical Center; 2Lamb Consulting The background is as follows. Proliferative urethritis (PU) is an uncommon inflammatory and infiltrative disease of the urethra in female dogs, often associated with a urinary tract infection (UTI). PU typically presents with evidence of a urethral obstruction (UO). The objective is as follows. To identify clinical features in dogs with PU and document outcomes after different treatment modalities. The animals are 11 client‐owned dogs. The methods are as follows. Medical records of dogs with a histopathologic diagnosis of PU from 2011–2020 were retrospectively evaluated, including information on clinical pathology, imaging, and histopathology. The outcomes of various treatment modalities were recorded and compared. Long‐term urethral patency (>6 months) was considered a treatment success. The results are as follows. All dogs were female and 8/11 (73%) had a history of UTI(s). Ten of 11 survived to discharge and were used for long‐term data collection. Seven of 10 dogs (70%) were treated with an effacement procedure (balloon dilation [BD] and/or stent) and 6/7 (86%) had urethral patency long term. Seven of 10 had UO recurrence after their first procedure, including 3/3 (100%) that did not have effacement and 4/7 that did (57%), at a median time of 101 and days, respectively. After effacement, the duration of patency was longer for those treated with a stent (retrievable/permanent) than BD alone (median 843 and 452, respectively). The conclusions and clinical importance are as follows. PU is a recurrent disease often associated with a UTI. The best chance long term urethral patency was after lesion effacement, either with BD or stenting (retrievable/permanent). Future prospective studies are needed to determine the impact of various immunosuppressive agents. ABSTRACT NU15 Symmetric dimethylarginine and creatinine concentrations in cats with ureteral obstruction before and after decompression Jessica Himelman 1; Allyson Berent2; Kendall Wilson2; Chick Weisse2; Donald Szlosek3; Michael Coyne3; Donald McCrann3 ; Rachel Murphy3 1Veterinary Emergency and Referral Group; 2The Animal Medical Center; 3IDEXX Laboratories Inc. The purpose of this study is to evaluate symmetric dimethylarginine (SDMA) and creatinine concentrations in cats presenting with ureteral obstruction(s) (UO), and to determine if pre‐decompression values are predictive of underlying renal function after decompression is accomplished with a subcutaneous ureteral bypass (SUB) device. Twenty‐five cats admitted for treatment of UO(s) were prospectively evaluated. Serum SDMA and creatinine concentrations were assessed at presentation, 24 hours, 1 week, 1 month, and 3 months post‐decompression. Urinalysis and urine culture were assessed at presentation, 1 month, and at 3 months post‐decompression. Cats were excluded if: they had bacterial growth on urine culture, evidence of re‐obstruction during the study period, additional surgical procedures during the study period, or if all samples were not able to be obtained at designated time points. A significant correlation was observed between the initial SDMA value and the initial creatinine value pre‐decompression (ρ = 0.871, p < 0.001). Both the initial mean creatinine, and the initial mean SDMA values pre‐decompression were shown to significantly decrease on all time points when controlling for individual patient effects (p < 0.001, p < 0.001, respectively). No significant correlation was observed between the initial SDMA value pre‐decompression and the 3‐month post‐decompression SDMA value (Figures 1 and 2, ρ = 0.270, p = 0.760). SDMA appears to be a useful marker of post‐renal azotemia in cats with UO. Pre‐decompression SDMA should not be used as a means to predict underlying renal disease and long‐term renal recovery in patients undergoing SUB device placement for decompression of their UO(s).   ABSTRACT NU16 Identification of a potential marker of immune complex mediated glomerulonephritis in canine urine Jessica A. Hokamp; Rachel Cianciolo; Jesssica Quimby; Andrew Reed The Ohio State University The most common causes of glomerular disease in dogs are immune complex mediated glomerulonephritis (ICGN), amyloidosis, and focal segmental glomerulosclerosis. A diagnosis of active ICGN prompts immunosuppressive therapy which is not recommended in other glomerular diseases. Renal biopsy is required for accurate diagnosis of glomerular disease in dogs, but there is significant interest in discovery of specific disease markers in samples collected by minimally invasive means (urine, blood). The objective of this study was to use liquid chromatography tandem mass spectrometry (LC‐MS/MS) for proteomic discovery of high molecular weight protein(s) that will accurately distinguish dogs with ICGN from dogs with non‐ICGN diseases. Urine from dogs with membranoproliferative glomerulonephritis (MPGN, a type of ICGN) (n = 9) and non‐ICGN diseases (n = 6, specifically, amyloidosis and focal segmental glomerulosclerosis) was analyzed with Tris‐Acetate gel electrophoresis to separate high molecular weight (MW) proteins. A distinct high MW band, present in MPGN cases but absent to faint in non‐ICGN cases, was excised from the gel lanes. Identical regions were excised from the lanes of non‐ICGN cases. These bands were trypsin digested followed by peptide extraction. Liquid chromatography tandem mass spectrometry (LC‐MS/MS) was performed on the extracted peptides to acquire MS/MS data. Sequence data was searched against the Canis lupus NCBI protein database. Total normalized spectral counts were used to quantify relative protein abundances. The excised band of interest contained a large protein, de‐identified as “Protein A", in 6 out of 9 (67%) of the MPGN cases and 1 out of 6 (17%) of the non‐ICGN cases. The mean number of peptides matching Protein A was significantly higher in dogs with MPGN (10.7 peptides) vs. non‐ICGN (0.24 peptides) (two‐sample Wilcoxon rank‐sum test, p = 0.03). Preliminary data suggests that urinary “Protein A" might be a marker of canine MPGN but additional work is needed to confirm these results in a greater number of cases. Future studies will also be expanded to include other forms of ICGN (membranous and mesangioproliferative glomerulonephritis). ABSTRACT NU17 Influence of a meal on serum concentrations of gut‐derived uremic toxins in healthy adult cats Stacie Summers 1; Jessica Quimby2; Linxing Yao3; Corey Broeckling3; Michael Lappin3 1Oregon State University; 2The Ohio State University; 3Colorado State University The main gut‐derived uremic toxins indoxyl sulfate (IS), p‐cresol sulfate (pCS), and trimethylamine‐n‐oxide (TMAO) are metabolites of dietary protein. This study assessed the short‐term effect of a meal on serum IS, pCS, and TMAO in healthy adult cats. Nine healthy research‐bred cats were enrolled, and jugular catheters were placed for repeat blood sampling. Cats were fed the same commercial dry cat food (8.74 g protein per 100 kcal) for at least 8 weeks prior to enrollment and during the study. After a 12‐hour fast, a blood sample was collected at hours 0800, 1000, 1200, 1400, 1600, 1800. The next day after a 12‐hour fast the cats were offered food at hour 0600 and a non‐fasted blood sample was collected at hours 0800, 1000, 1200, 1400, 1600, and 1800. Total IS, pCS, and TMAO serum concentrations were determined by liquid chromatography‐tandem mass spectrometry. A paired t test or Wilcoxon matched‐pairs signed rank test was used to compare serum concentrations between the fasted and non‐fasted state. A one‐way ANOVA with Geisser‐Greenhouse correction or Friedman test was used to compare serum concentrations between the collection time points throughout the day. A p value ≤0.05 was considered significant. Serum pCS concentrations were significantly lower in the non‐fasted state when compared to the fasted state at hours 1000 (p = 0.004) and 1200 (p = 0.008). Serum IS concentrations were significantly lower in the non‐fasted state when compared to the fasted state at hours 1000 (p = 0.006), 1200 (p = 0.005), 1400 (p = 0.050), and 1800 (p = 0.026). Serum TMAO concentrations were significantly lower in the non‐fasted state when compared to the fasted state at hours 0800 (p = 0.005), 1000 (p < 0.001), 1200 (p < 0.001), 1400 (p < 0.001), 1600 (p < 0.001), and 1800 (p < 0.001). Serum concentrations differed between multiple collection time points for IS in the non‐fasted (p = 0.001) and pCS in the fasted state (p < 0.001). In conclusion, feeding may reduce serum concentrations of pCS, IS, and TMAO over a 12‐hour period in cats. To compare serial measurements, it would be prudent to collect samples at the same time of day and consistently in either a fasted or non‐fasted state. ABSTRACT NU18 Dietary potassium chloride promotes urine dilution and lowers relative supersaturation in dogs and cats Esther Bijsmans; Vincent Biourge; Yann Quéau Royal Canin Prevention of calcium oxalate (CaOx) urolithiasis is challenging, and crystallization risk can be decreased by balanced dietary minerals in combination with urine dilution. Sodium chloride is often used as a strategy to promote urine dilution. The effect of potassium chloride (KCl) salt on urine parameters is less known. This study aimed to investigate the effects of increasing levels of KCl on urine dilution and struvite and CaOx relative supersaturation (RSS) as a measure of crystallization risk. Three dry extruded maintenance diets were manufactured using the same base formula, but supplemented with KCl to reach K+ of 1.56 g/Mcal (Diet A), 3.35 g/Mcal (Diet B) and 4.62 g/Mcal (Diet C). Macronutrients and minerals did not differ between diets, including sodium, which was 1.0 g/Mcal in all. Diets were fed in a cross‐over fashion to 9 healthy adult cats and 5 healthy adult Miniature Schnauzers for 7 days, followed by 3 days of urine collection. Water intake and urine volume were recorded. Urinary ions were measured on the pooled urine sample using ionic chromatography. Struvite and CaOx RSS were calculated using SUPERSAT software. Data was log‐transformed if needed depending on the residuals to meet statistical assumptions of the model. Mixed effect models were used to investigate the effect of diet on water intake, urine volume, urine‐specific gravity, struvite, and CaOx RSS, using animal as a random term. Data is presented as mean ± SD except for struvite which is presented as median [25th, 75th percentile]. Post‐hoc comparisons were performed using Tukey's HSD. Results are presented in the table. In conclusion, increasing dietary KCl leads to an increased water intake, increased urine volume and decreased USG in healthy dogs and cats, in a linear fashion. Struvite RSS significantly decreases in cats, but no significant difference is found in dogs. Median struvite RSS is undersaturated on all diets. CaOx RSS is significantly lower on the diets with the highest potassium content compared to the diets with the lowest potassium content in both dogs and cats. These results suggest that KCl can be used effectively to dilute urine and decrease crystallization risk in both dogs and cats.   ABSTRACT NU19 The effect of attenuating dietary phosphate restriction in cats with azotemic CKD and ionized hypercalcemia Rebecca F. Geddes; Henk Van den Broek; Yu‐Mei Chang; Rosanne Jepson; Jonathan Elliott Royal Veterinary College Dietary phosphate restriction may contribute to hypercalcemia development in some cats with CKD. Optimal dietary management strategy for these individuals is unclear. A database of cats diagnosed with azotemic CKD from 1/1/14–7/1/18 was searched for cats with ionized hypercalcemia at time of CKD diagnosis (ionized [calcium] on iSTAT (iCa) >1.40 mmol/l; “baseline hypercalcemics”), or after feeding a clinical renal diet ([iCa] >1.50 mmol/l once or persistently >1.40 mmol/l; “RD hypercalcemics”). Of 48 hypercalcemic cats identified, 28 were transitioned onto Royal Canin Senior Consult Stage 2 (RCS2; 1.5 g/Mcal phosphorus; Ca:P ratio 1.3), a moderately phosphate‐restricted diet. Twenty cats were excluded as they lacked baseline [iCa] data (n = 3), received prednisolone (n = 3) or were not offered RCS2 (n = 14). Variables over time were assessed using linear mixed models within groups, with visit 1 (v1) taken as the date RCS2 was initiated. Data are presented as median [25th,75th percentile]. Eighteen of 28 cats transitioned onto RSC2 had follow‐up data. Nine were baseline hypercalcemics with v1 iCa 1.47[1.42,1.55] mmol/l, and 9 were RD hypercalcemics (hypercalcemia identified 148 [110,236] days after CKD diagnosis) with v1 [iCa] 1.52[1.51,1.62] mmol/l). Blood iCa (coefficient (β), −0.030; 95% confidence interval; −0.048 to −0.012; p = 0.003) significantly decreased when RD hypercalcemics were fed RCS2, with [iCa] decreasing to <1.4 mmol/l in 8/9 cats after 67 [56,112] days. Plasma phosphate did not change. These variables did not change in baseline hypercalcemics (follow‐up 273[147,325] days on RCS2 diet). Attenuation of dietary phosphate restriction could normalize [iCa] in cats that develop hypercalcemia whilst eating a clinical renal diet. ABSTRACT NU20 Urinary fibrinogen and the development of Enterococcus spp. bacteriuria in dogs Michael Wood; Adam Lepold; Dahlia Tesfamichael University of Wisconsin‐Madison In humans, increased urinary fibrinogen concentration induces Enterococcus spp. bacteriuria. Commonly this fibrinogenuria occurs secondary to urinary catheter induced urothelial trauma. Routine catheterization of canine patients is relatively uncommon; however, the prevalence of Enterococcus spp. in dogs with recurrent bacteriuria (17–25%) is increased when compared to dogs with all forms of bacteriuria (8.8–11.3%). This study hypothesizes that previously identified Enterococcus spp. bacteriuria risk factors in dogs (uroliths, lower urinary tract (LUT) neoplasia, and anatomic abnormalities of the LUT) will similarly be associated with increased urinary fibrinogen concentrations. To test this hypothesis urine culture negative samples were collected from 46 risk factor dogs including 8 dogs with uroliths, 27 with LUT neoplasia, and 11 with LUT anatomic abnormalities. Healthy control dogs numbered 21. Urine fibrinogen concentrations were measured with an optimized canine urine‐specific fibrinogen ELISA and normalized by calculating a urine fibrinogen:creatinine ratio. In total 46 risk factor dogs had a median urinary fibrinogen:creatinine ratio of 2.87 compared to 0.17 in the healthy group (p < 0.05). The LUT neoplasia group had the highest median fibrinogen:creatinine ratio (5.52; p < 0.05) followed by uroliths (0.72; p < 0.05) and LUT anatomic abnormalities (0.48; p > 0.05). This study concludes that urinary fibrinogen concentrations are elevated in dogs with LUT neoplasia and uroliths as compared to healthy dogs. This hyperfibrinogenuria may be predisposing these dogs to Enterococcus spp. Bacteriuria; however, other factors are also likely important given that increased urinary fibrinogen was not identified in dogs with LUT anatomic abnormalities. ABSTRACT NU21 The effects of calcifediol supplementation on the renin‐angiotensin‐aldosterone system in dogs with chronic kidney disease Matthew S. Miller 1; Jessica Quimby1; Catherine Langston1; Marisa Ames2; Valerie Parker1 1The Ohio State University; 2Colorado State University Increased renin‐angiotensin‐aldosterone system (RAAS) metabolite concentrations instigate pro‐fibrotic and pro‐inflammatory changes within the kidney, potentially leading to worsening chronic kidney disease (CKD). While vitamin D metabolites have been shown to ameliorate activation of RAAS, CKD leads to decreased serum vitamin D metabolite concentrations. We hypothesize that supplementation with calcifediol (25‐hydroxyvitamin D) will decrease circulating RAAS mediators in dogs with CKD. In a pilot study, 10 dogs with International Renal Interest Society (IRIS) stage 2 and 3 CKD received an oral extended release calcifediol supplement for 3 months. Dogs were evaluated at baseline, then after 3 months of calcifediol supplementation, and again 2 months later after discontinuation of calcifediol. Serum concentrations of 25‐hydroxyvitamin D [25(OH)D] and RAAS mediators (angiotensin I/II/III/IV/1‐5/1‐7, and aldosterone) were evaluated at all time‐points. RAAS mediators were evaluated using a novel liquid‐chromatography‐tandem mass spectroscopy assay (RAS‐Fingerprint™). The ratio of angiotensin II to angiotensin I served as an indicator of angiotensin‐converting enzyme (ACE) activity. Six dogs were included in analysis after exclusion of four dogs for use of RAAS‐inhibitors (enalapril n = 2, telmisartan n = 1) or lack of study completion (n = 1). Friedman's repeated‐measures test with Dunn's post‐test was utilized for analysis. With calcifediol supplementation, 25(OH)D concentration significantly increased (*p = 0.03), and ACE activity significantly decreased (**p = 0.01) (Figure 1). Serum concentrations of variables (median, range) in 6 dogs at baseline, after 3 months of calcifediol supplementation, and 2 months after calcifediol discontinuation are listed in Table 1. There was no significant difference in angiotensin II, angiotensin 1‐5, and angiotensin 1‐7 at any time‐point. In conclusion, short‐term calcifediol supplementation in this small subset of CKD dogs affected ACE activity Variable 25(OH)D (ng/ml) ACE activity Angiotensin I (pmol/L) Angiotensin II (pmol/L) Aldosterone (pmol/L) Baseline 43.2 (33.8–58.3) 0.67 (0.61–1.28) 31.3 (13.2–75.9) 22.4 (17.0–46.3) 29.2 (7.5–85.8) Month 3 249.9 (204.2–310.3)* 0.55 (0.37–1.00)** 55.5 (29.2–111.4) 31.1 (12.1–60.7) 126.9 (7.5–301.2) Month 5 68.6 (49.4–107.6) 0.63 (0.58–1.32) 31.2 (20.2–77.3) 25.7 (14.7–46.6) 62.0 (25.0–122.6)   ABSTRACT NU22 The use of a 3D‐ultrasound device to investigate urinary retention in hospitalized dogs Edward J. Vasquez 1; Allison Kendall1; Sarah Musulin2; Shelly Vaden2 1North Carolina State University; 2College of Veterinary Medicine, North Carolina State University Urine residual volume (URV) is the volume of urine remaining in the bladder immediately after the completion of voiding and is a clinically important measurement for assessing bladder function. URV > 1 ml/kg can lead to serious clinical consequences such as detrusor atony and urinary tract infection. Multiple factors, such as anesthesia and surgery have been implicated to cause postoperative urinary retention in people, which has led to routine bladder monitoring. Monitoring for urinary retention in hospitalized canine patients is not routinely performed yet urine retention may result in clinical repercussions. URV can be measured directly via urethral catheterization or indirectly via 2D ultrasound formulas. However, these techniques may impose risks such as sedation‐related adverse events or catheter‐associated urinary tract infection, and require appropriate operator skill and equipment. Clinical application of a 3D ultrasound device has been used for volumetric assessments of the canine urinary bladder and is routinely used for fast, ‘bedside’ estimation of urinary bladder volumes in people. This study aims to investigate the degree of urinary retention in hospitalized dogs using a 3D ultrasound device, and to describe various factors that could be contributing to urinary retention. We hypothesized that the majority of hospitalized dogs would develop a degree of urinary retention, and that various factors such as anesthetic events or use of opioids would contribute. A total of 25 hospitalized dogs were enrolled in this prospective, observational study. All dogs were hospitalized for more than 24 hours, and had no apparent concurrent urinary or neurologic disease that would impact their ability to ambulate or voluntarily urinate. Pre‐ and immediately post‐void bladder volumes were measured with a 3D ultrasound device within 12 hours of presentation; subsequent measurements were obtained throughout the duration of hospitalization at approximately the same time each day. Urine retention was observed in all hospitalized dogs as manifested by increased URV. This was evident regardless of the length of hospitalization; however, the majority of dogs experienced the greatest degree of urinary retention on the second day. Of the 25 dogs enrolled, 18 dogs had an anesthetic event during their hospitalization. Of these dogs, 15/18 (83%) had URV above the reported normal reference range (0.2–0.4 ml/kg) with an average of 4.34 ml/kg (0.5–13.4 ml/kg). URV is an important clinical measurement that directly assesses bladder function and urine retention in dogs. We have determined that a ‘cage‐side’ 3D ultrasound device can be used to safely and efficiently measure daily urinary bladder volume in hospitalized dogs. Daily monitoring of hospitalized dogs, particularly those who have undergone an anesthetic event, could help in early identification and intervention of patients that are retaining urine, thereby preventing the adverse effects of urinary retention. Further studies are warranted to determine if urinary retention is persistent after discharge in those dogs that had increased URV during hospitalization. ABSTRACT NU23 Urethral tissue engineering for canine urinary incontinence Hilla Chen 1; Anna Shipov1; Shai Sherbo2; Keren Sinik2; Ishay Attar2; Gilad Segev1 1Koret School of Veterinary Medicine, The Hebrew University of Jerusalem; 2BioChange Ltd. Urinary incontinence is a common medical concern in female dogs, most commonly caused by urethral sphincter mechanism incompetence (USMI). Disadvantages of medical therapy include the need for lifelong treatment, potential side effects and incomplete response in some dogs. VetFoam™ is an injectable scaffold made of natural materials, biocompatible and biodegradable. In this study, scaffold and saline (control) were locally injected into the urethra and sub‐cutaneous tissue of a pig. Injection sites were sampled 15, 30, 60, 90 or 140 days (skin and urethra, respectively) post‐injection. Masked histopathological evaluation using semi‐quantitative scoring method (grade 0–4) was used to describe collagenesis along with scaffold resorption. VetFoam™ was than examined clinically by endoscopically guided injections to the proximal urethra of 15 client‐owned, incontinent females dogs diagnosed with USMI. Continence score (CS) was assigned (1–5 scale) before and after the procedure and monthly thereafter. Histopathology of porcine tissue showed new tissue formation within ~90 days, while the implanted scaffold was undetectable by that time. Collagenesis grade was 3–4 in VetFoam™ injected tissue compared to 0 in control sites. No inflammation, necrosis, cavity formation or edema were documented. Median post‐procedural CS of dogs increased from baseline (1.5 vs. 4, respectively, p < 0.001), mean continence duration was 11.3 ± 11.0 months. VetFoam™ promote collagenesis and thus has potential to maintain continence longer compared with other bulking agents. The clinical effect demonstrated in dogs, exceeded the time to full scaffold degradation, hence VetFoam™'s efficacy is likely the outcome of tissue remodeling, rather than of a bulking effect. ABSTRACT NU24 Influence of laboratory parameters on survival in dogs with chronic kidney disease Vivian Pedrinelli; Fabio Teixeira; Mariana Porsani; Andressa Amaral; Marcia Kogika; Marcio Brunetto University of Sao Paulo Chronic kidney disease (CKD) is one of the most common diseases in dogs. Factors such as creatinine, phosphorus, and albumin serum concentrations may influence survival of dogs with this disease. However, information on the influence of other laboratory parameters on survival of these animals is scarce. The aim of this study was to evaluate retrospectively the relationship between survival in dogs with CKD and common laboratory parameters evaluated in this disease. A total of 116 dogs with CKD stages 2 to 4 were included. Kaplan‐Meier curves and log‐rank test were used to compare survival of dogs according to stage of disease, serum phosphorus, albumin, and hematocrit. p values <0.05 were considered significant. Stage of disease (p < 0.0001), serum phosphorus (p = 0.0005), and hematocrit (p = 0.0001) influenced on survival. Dogs with serum phosphorus below 5.5 mg/dL had an increase of 4.21 times in the survival, and dogs with hematocrit higher than 37% presented an increase of 4.19 times in the survival. Albumin concentration, however, did not influence survival in dogs with CKD (p = 0.2260). According to the results observed in this study, early diagnosis, along with proper laboratory evaluation, are determinant strategies to extend survival in dogs with CKD.1 REFERENCE IRIS (2019). Available at www.iris-kidney.com/guidelines/staging.html. ABSTRACT NU25 Reduced dietary sodium and calcium improves urine stability in dogs Jennifer M. MacLeay ; Stephen Davidson; Kathy Gross Hill's Pet Nutrition, Inc. Calcium oxalate urolithiasis is common in dogs and humans and recurrence rates are 40% within 2 and 10 years, respectively.1,2 Nutritional recommendations in people to reduce risk commonly includes increased water intake and reduced dietary protein and oxalate.3,4 In veterinary medicine salt may be recommended to increase thirst and water intake, whereas it is not recommended in human medicine5,6 as dietary sodium increases urinary calcium.7 Increased dietary sodium associated with increased urine calcium has also been shown in cats.8 Increased urinary calcium can lead to urine instability as measured by a urine calcium oxalate titration test (COTT), which has also been used to evaluate risk for calcium oxalate recurrence in humans9 and the test has been adapted for use in cats.10 Foods rich in antioxidants and fatty acids and reduced in sodium have shown significant improvements in COTT and urine calcium concentration in cats.11,12 In this study, a dry dog food with added fatty acids and antioxidants and relatively lower in sodium and calcium (Food A; Na 0.3%, Ca 0.7% DMB) was compared with a higher sodium and calcium food (Food B; Na 0.5%, Ca 1.6% DMB), and urine parameters related to risk for calcium oxalate were compared. All procedures were approved by an internal animal care and use committee and dogs had opportunities to exercise indoors and outdoors throughout the study. In succession, ten healthy adult dogs consumed a test (A) and a control (B) food for 14 days and on the last day of each trial all urine voluntarily voided over a 24‐hour period was collected into a closed system where urine was maintained at body temperature until laboratory testing. Urine pH was measured using a calibrated meter. The COTT was performed by titrating whole urine with a sodium oxalate solution and monitored at 585 nm until precipitation occurred according to the method described by Davidson.10 RSS for calcium oxalate and struvite were calculated using EQUIL software using urinary concentrations of NH4 +, Ca+2, Cl−, citrate, creatinine, Mg+2, oxalate, PO4 −3, K+, Na+, SO4 −2 and urine pH. A one tailed T‐Test was performed and significance was set at p < 0.05. Dogs consuming Food A had significantly reduced urine sodium and calcium, urine‐specific gravity, and RSS Struvite compared to Food B. The urine was more stable as evidenced by a significantly reduced calcium oxalate titration test result. In this study, differences in urine composition that impacted urine stability were better reflected by the COTT test than RSS calculation for calcium oxalate. Similar to people and cats, feeding foods with higher calcium and sodium levels may result in greater risks for calcium oxalate stones as measured by a urine stability test. REFERENCES 1. Lulich. JVIM 1992. 2. Singh. Mayo Clin Proc 2015. 3. Worcester. NEJM 2010. 4. Queau. VCNA 2019. 5. Delaney and Fascetti. Nutritional Management of Uroliths; 2016. www.vetmed.ucdavis.edu/hospital/animal-health-topics/urolithsv4-04. Accessed January 16, 2020. 6. Ticinesi et al. NDT. 7.Nouvenne et al. AJCN 2009. 8. Gluhek. JVIM 2012. 9. Laube. Urol Res 2000. 10. Davidson. JVIM 2015. 11. MacLeay. JVIM 2015. 12. MacLeay. JVIM 2018. ABSTRACT NU26 Fecal primary and secondary bile acids in cats with chronic kidney disease Stacie Summers 1; Jessica Quimby2; Jenessa Winston2 1Oregon State University; 2The Ohio State University Cats with chronic kidney disease (CKD) have an intestinal dysbiosis. Primary bile acids are converted to secondary bile acids by intestinal microbiota and fecal concentrations may be altered with dysbiosis. To date, fecal bile acids have not been quantified in CKD cats, therefore the objective of this study was to compare fecal bile acid concentrations in cats with CKD and compare to a group of healthy senior cats. Voided feces was collected from healthy senior cats (≥8 years; n = 10) and cats with CKD (IRIS stage 2, n = 17; IRIS stages 3 and 4, n = 12). Major primary and secondary bile acids in feces were measured by liquid chromatography with tandem mass spectrometry. Fecal bile acids were compared between groups with Mann‐Whitney test and Kruskal‐Wallis test with Dunn's multiple comparisons test. A Spearman rank was used to assess correlation between serum creatinine and fecal bile acid concentrations. A p value ≤0.05 was considered significant. The primary bile acids cholic acid and chenodeoxycholic acid and the secondary bile acids lithocholic acid and deoxycholic acid were not significantly different between healthy senior cats and CKD cats. The secondary bile acid ursodeoxycholic acid (UDCA) was significantly lower in CKD cats (median, 12.9 ng/mg; range, 0–166.0 ng/mg) when compared to healthy senior cats (median, 32.2 ng/mg; range, 9.4–56.2 ng/mg; p = 0.051). Stages 3 and 4 CKD cats (median, 6.5; range, 0–166 ng/mg) had significantly lower fecal UDCA concentrations when compared to healthy senior cats (p = 0.043). No significant difference in fecal UDCA concentrations was found between healthy senior cats and stage 2 CKD cats (p = 0.696) and between stage 2 CKD cats and stages 3 and 4 CKD cats (p = 0.386). Fecal UDCA concentrations weakly correlated with serum creatinine concentrations (p = 0.041; ρ = −0.328). In conclusion, fecal UDCA concentrations are significantly decreased in cats with CKD, especially cats with late‐stage disease. ABSTRACT NU27 Urinary 15‐F2‐isoprostanes in dogs with transitional cell carcinoma and other lower urinary tract disease Andrew Woolcock; Adrienne Cheney Purdue University Transitional cell carcinoma (TCC) is the most common type of urinary bladder tumor in dogs. Signs of lower urinary tract disease like dysuria from tumor size/obstruction or secondary urinary tract infections may prompt evaluation in these cases, but often this leads to a late diagnosis of the tumor. In people, oxidative stress is implicated in the carcinogenesis of tumors of the stomach, colon, liver, and urogenital tract. By‐products of oxidative damage, such as the F2‐isoprostanes, can be easily measured in urine. In people, urinary F2‐isoprostanes are increased in men with lower urinary tract diseases and prostatic carcinoma, with carcinoma patients demonstrating the highest magnitude increase in urinary F2‐isoprostanes. Urinary F2‐isoprostanes have not been evaluated in canine urogenital tumors. The objective of this study was to measure urinary F2‐isoprostanes in dogs with TCC as well as in dogs demonstrating signs of lower urinary tract disease (LUTD). We hypothesized that urinary F2‐isoprostanes would be increased in dogs with TCC and LUTD when compared to healthy controls. We further hypothesized that urinary F2‐isoprostanes would be increased in dogs with TCC when compared to dogs with LUTD. Dogs with newly diagnosed, histologically confirmed, TCC of the urinary tract were eligible for inclusion in the study, and were excluded if they had received any non‐steroidal anti‐inflammatory drugs (NSAID), corticosteroids, or cytotoxic chemotherapeutic agents within 30 days of presentation. Dogs with other, non‐neoplastic, lower urinary tract disease (LUTD) were eligible for inclusion as well, with LUTD defined by the presence of dysuric clinical signs including stranguria, pollakiuria, or urinary incontinence. Urine was collected by mid‐stream voided collection, sterile urethral catheterization, cystocentesis, or collection through cystoscopy. Gas chromatography‐negative ion chemical ionization‐mass spectrometry (GC‐NICI‐MS) was performed for quantification of F2‐isoprostanes in all samples, with values normalized to urine creatinine. All dogs also had a concurrent urinalysis performed. Isoprostane measurements were parametrically distributed with summary descriptive statistics presented as mean + SD and assessed by one‐way ANOVA. All other data were non‐parametrically distributed with summary descriptive statistics presented as median [range]. Nonparametric numerical data for groups was assessed with the Wilcoxon rank sum test. Seventy‐six dogs were included in the study, with 46 dogs diagnosed with TCC and 30 dogs diagnosed with LUTD. The most common LUTD diagnosed were cystitis (n = 16; n = 8 bacterial cystitis, n = 8 lymphocytic and other sterile cystitis). The urinary F2‐isoprostanes did not differ between the dogs with TCC, LUTD, or control dogs (mean + SD, TCC 6.58 + 6.37 vs. LUTD 5.52 + 3.13 vs. control 4.23 + 1.60, p = 0.07). Dogs with TCC had higher qualitative measures of proteinuria (p = 0.004), microscopic hematuria (p = 0.013), and epithelial cells noted on sediment examination (p = 0.002) compared to the other two groups. Urinary F2‐isoprostanes do not appear to be a useful biomarker in the diagnosis of TCC in dogs, but further research is required to determine if urinary F2‐isoprostanes decrease during treatment of lower urinary tract diseases and neoplasia in dogs. ABSTRACT NU28 Transient increase in serum symmetric dimethylarginine level during anesthesia in cats undergoing routine dental procedures Ira Roth; Sara Gonzalez; Alison Meindl College of Veterinary Medicine, University of Georgia Renal function is traditionally monitored by serum levels of creatinine and BUN even though marked renal dysfunction must occur prior to elevation in these markers. Symmetric dimethylarginine (SDMA) is a functional renal biomarker that correlates with glomerular filtration rate (GFR) and has been shown to be more sensitive than creatinine or BUN. The purpose of this study was to evaluate the immediate and residual effect of anesthesia on common renal function biomarkers in 12, client‐owned cats that were anesthetized for routine dental procedures. Samples were collected at 3 timepoints: post 8 hour fast, but prior to anesthesia (baseline), post‐surgery (extubation), and at a 14‐day follow‐up, unfasted (day 14). SDMA, creatinine, BUN, and urine‐specific gravity (USG) were determined at each time point. Two of the study cats were previously diagnosed with IRIS Stage 2 CKD. Differences in renal biomarkers and USG at each timepoint were tested with paired Wilcoxon Rank Sum tests, with p‐values adjusted for multiple comparisons using the Holm‐Bonferroni method. All tests in this study used a significance threshold of p < 0.05. Median SDMA concentrations increased by 4 μg/dl between baseline and extubation (10 μg/dl to 14 μg/dl). This represents a significant increase (p = 0.002) in SDMA from baseline to extubation. (Figure 1) At the 14 day recheck, SDMA concentrations, though lower than baseline, were not significantly different from baseline concentrations (p = 0.393). No significant increases were observed in creatinine concentrations from baseline to extubation (p = 0.324), and while BUN concentrations increased in some cats from baseline to extubation, the increase was not significant (p = 0.152). USG values did not significantly change from baseline to extubation (p = 0.221). At the 14 day recheck, creatinine concentrations, BUN concentrations, and USG values were not significantly different from baseline (p > 0.3). Length of anesthesia, body temperature, and volume of fluids administered during anesthesia were not significantly correlated with changes in SDMA levels from baseline to extubation tested with Spearman's Rank Correlation. In this study, SDMA was the only renal biomarker that increased in cats following routine dental procedures. These data support that GFR decreases in cats undergoing routine dental procedures, likely because of anesthesia, and that SDMA is the only renal biomarker sensitive enough to detect this change. The return of SDMA levels to within the reference interval two weeks post anesthesia suggests that GFR changes associated with anesthesia are transient and returns to pre‐anesthesia levels in cats.   ABSTRACT NU29 Survey of litter box defecation habits in apparently healthy and chronic kidney disease cats Sarah Jones 1; Jessica Quimby1; Sarah Caney2; Sierra Adams1; Stacie Summers1; Adam Rudinsky1 1The Ohio State University; 2Vet Professionals Ltd Changes in bowel movements (BM) are an important clinical sign in many diseases, including chronic kidney disease (CKD), and the purpose of this study was to collect information on BM and fecal score (FS) in both apparently healthy and CKD cats. A secondary aim was to assess owner awareness of BM frequency. Owners were asked to complete an initial online questionnaire about their cat's health (to corroborate health status) and litter box habits (including predicted BM frequency and FS). Owners were then asked to clean the box daily for 7 days and report results (observed frequency of BM and FS) daily using Purina Fecal Score (1–7) to assess feces. Differences in BM frequency and FS between apparently normal and CKD cats were compared using Mann‐Whitney test and predicted versus observed data were compared using Wilcoxon sign rank test. Difference in percentage of cats defecating more or less than once daily were assessed with Fishers exact test. Survey data from 124 owners of apparently healthy cats and 43 owners of CKD cats who submitted two or more days of daily observations (in addition to the initial questionnaire) were analyzed. Age (years) of healthy cats was reported as 15+ (6.4%), 11–14 (13.2%), 7–10 (20.1%), 1–6 (55.2%), or <1 (4.3%). Age of CKD cats was reported as 15+ (62.8%), 11–14 (23.3%), 7–10 (9.3%), 1–6 (4.7%). Median serum creatinine (reported in n = 26 CKD cats) was 2.5 mg/dL (range 1.6 mg/dL to 3.3 mg/dL). Eighty‐five percent of apparently healthy cats were observed to defecate one or more times per day and 15% defecated less than once per day. Fifty‐eight percent of CKD cats defecated one or more times per day and 42% defecated less than once per day. A significantly higher percentage of CKD cats defecated less than once per day in comparison to apparently healthy cats (p < 0.0001). Data for predicted and observed BM frequency and FS are presented in Table 1. Observed BM frequency was significantly less in CKD cats compared to healthy cats (p = 0.02). Owner predicted BM frequency was significantly different than observed BM frequency in healthy cats (p = 0.04), but not in CKD cats. Owner predicted FS was significantly different than observed FS in healthy cats (p = 0.01), but not in CKD cats. Observed FS was not significantly different between healthy and CKD cats (p = 0.16). In conclusion, the observed BM frequency of cats with CKD was less than apparently healthy cats and represents a clinically important variation from normal. Predicted Avg BM/day* Observed Avg BM/day* Predicted Avg FS Observed Avg FS Healthy Cats Mean ± SD 1.16 ± 0.5 1.29 ± 0.6 2.14 ± 0.5 2.08 ± 0.5 Median (range) 1.0 (0.14 to 3.0) 1.0 (0.33 to 3.3) 2.0 (1.0 to 4.0) 2.0 (1.0 to 4.0) CKD Cats Mean ± SD 0.88 ± 0.3 1.12 ± 0.6 2.34 ± 1.1 2.19 ± 0.9 Median (range) 1.0 (0.33 to 2.0) 1.0 (0.25 to 3.5) 2.0 (1.0 to 5.0) 2.0 (1.0 to 5.5) *Predicted Avg BM/day: 0.33=every third day, 0.25=every fourth day, 0.14=once per week   6 ABSTRACT NU30 Survey of the practice of canine and feline urinalyses in the United States and Canada Nicole H. Gibbs 1; Johanna Heseltine2; Mark Rishniw3; Mary Nabity2 1Texas A&M University, College of Veterinary Medicine & Biomedical Sciences; 2Texas A&M University; 3Veterinary Information Network; Cornell University Although urinalysis is a common diagnostic tool, no known studies describe factors influencing the performance of urinalyses by small animal practitioners. A survey was developed and posted on the Veterinary Information Network (VIN), enlisting veterinarians who perform urinalyses for dogs and cats. After answering general questions, participants were directed to question banks based on whether urinalyses are performed in‐house, by an outside diagnostic laboratory, or using an in‐house automated instrument. Participants using multiple methods were directed to questions from each appropriate question bank. A total of 1,059 participants from the United States and Canada completed the survey (86.6% from the United States). Of the practices surveyed, 90.9% were first opinion practices with 70% seeing exclusively dogs and/or cats, and 73.6% of the participants worked in practices with >1 full‐time veterinarian. Participants performed a median of eight urinalyses per week. Practitioners performed urinalyses much less frequently than blood work during routine examination. For example, in patients over 7 years of age, the number of veterinarians who always performed urinalyses (n = 142) was considerably fewer than the number who always performed a CBC (n = 544) or chemistry panel (n = 614). The most common factors preventing veterinarians from performing a urinalysis with blood work included clients' financial constraints (n = 447), difficulty obtaining urine (n = 365), and the veterinarian considering it unwarranted (n = 315). Approximately 29% of participants performed urinalyses in‐house by manual examinations and by submission to outside laboratories, whereas 11% exclusively sent urinalyses to outside laboratories, 23% exclusively performed in‐house urinalyses with manual examinations, and 11% used automated dipstick readers and/or sediment analyzers. For participants who sent urinalyses to diagnostic laboratories and performed in‐house manual examinations, the median percentage of samples sent to diagnostic laboratories was 50%. The most common reasons for submission to a diagnostic laboratory included efficiency, more trusted results, and convenience. Speed of obtaining results was the most common reason for performing urinalyses in‐house. Of the participants that performed in‐house urinalyses, only 57% always performed a sediment examination. Although urinalyses are commonly utilized in veterinary practice, major factors including finances, urine collection, efficiency, and lack of perceived expertise may contribute to urinalyses being an underutilized diagnostic tool. ABSTRACT NU31 Plasma copeptin concentrations in dogs with chronic kidney disease Ya li Chang; Ya‐Jane Lee; Pei‐Shiue Tsai Institute of Veterinary Clinical Science, National Taiwan University Arginine vasopressin (AVP or antidiuretic hormone) plays a dual role in physiology. First, AVP is responsible for osmoregulation by facilitating water transport in the collecting duct; second, AVP can constrict arterioles to increase arterial blood pressure. Thus, the abnormal AVP secretion can be the cause and consequence of a declined renal function. However, due to the unstable characteristics of the circulated AVP, the measurement of AVP concentration is unlikely reliable. However, the activation of AVP system stimulates the secretion of copeptin, a C‐terminal part of the pre‐provasopressin (pre‐pro AVP) in equimolarity with AVP. Therefore, copeptin directly reflects AVP concentration and can be used as a surrogate marker of AVP secretion. Recent studies suggested that increased copeptin level was associated with worse outcomes in chronic kidney disease (CKD) including microalbuminuria, hypertension, renal function decline, renal cyst formation and decreased kidney length in humans. Furthermore, copeptin was considered as an early predictor of kidney disease and cardiorenal syndrome in both human and laboratory animals. However, the information of copeptin in kidney diseases remains largely unknown in small animals. The aim of current study was to characterize plasma copeptin in dogs with CKD. Canine plasma samples were collected in the National Taiwan University Veterinary Hospital. Signalment, clinical information including history, physical examination and results of the hematology, plasma biochemistry and urinalysis of each case were recorded. Control groups (11 dogs) was defined as the dogs without any clinical signs associated with any disease, and no remarkable physical examination findings, as well as with the normal values of hematology, plasma biochemistry (BUN < 30 mg/dL, creatinine < 1.4 mg/dL) and urinalysis. The dogs with azotemia (creatinine > 1.4 mg/dL) and with the history and clinical signs related to renal disease and/or abnormal kidney image (small irregular kidneys and decreased corticomedullary distinction) for at least 3 months were enrolled into CKD group. Excluding criteria included post‐renal cases (obstruction in the lower urinary tract, lower urinary tract infection or cystitis), and with concurrent diseases other than kidney diseases. The CKD group was further classified into 4 subgroups based on the IRIS staging system; in total, 5 dogs in stage 1, 15 dogs in stage 2, 10 dogs in stages 3 and 5 dogs in stage 4. In addition, stages 1 and 2 of CKD stage were grouped as early stage, while stages 3 and 4 were late stage. Progression was defined as a 0.5 mg/dL increment in creatinine level or death within the 6 months. Progression day was also recorded. Blood osmolarity was derived from the formula of 2 (Na mmol/L + K mmol/L). Plasma copeptin concentration was determined with the average of duplicated tests by a commercial ELISA kit. Results showed that plasma copeptin concentrations were significantly decreased in CKD group (median [IQR]2.717 [2.08–5.29] pmol/L), as compared with those in the control group (3.994 [3.107–6.278] pmol/L) (p = 0.049). Linear regression analysis indicated plasma copeptin levels were significantly decreased with the increase of creatinine (B = 0.092, p = 0.004), urine‐specific gravity (B = 0.033, p = 0.002), potassium (B = 0.136, p = 0.007), and urine protein‐creatinine ratio (B = 0.153, p = 0.032), while it increased with the increments of BUN (B = 1.211, p = 0.014), PCV (B = 1.419, p < 0.001), sodium (B = 4.452, p = 0.005), systolic blood pressure (B = 10.912, p = 0.005), and blood osmolarity (B = 9.59, p = 0.006). However, plasma copeptin levels had no significant difference between progression and non‐progression cases in CKD group (p = 0.222) and between the cases with and without antihypertensive medicine which included angiotensin converting enzyme inhibitors (ACEi) (p = 0.538, n = 35), and calcium channel blocker (p = 0.281, n = 33). In conclusion, similar to results of the studies of human and laboratory animals, plasma copeptin level in canine CKD was related with hypertension and several parameters responsible for osmoregulation in our study; however, plasma copeptin decreased in the CKD cases. Furthermore, an inverse correlation between plasma copeptin and creatinine, proteinuria and urine‐specific gravity individually were noticed, which was different from those in human and laboratory animal studies. Table 1. Simple linear regression analysis of different parameters and plasma copeptin in all cases Parameters B value Adjustment β 95% CI for B value p value Age (year‐old) 0.022 0.063 ‐0.085–0.12 0.680 Hematocrit (%) 1.419 0.490 0.662–2.17 <0.001 ** Albumin (g/dL) 0.604 0.083 ‐0.009–0.015 0.604 Glucose (mg/dL) 0.162 ‐0.179 ‐0.513–0.18 0.352 BUN (mg/dL) 1.211 0.358 0.252–2.17 0.014* Creatinine (mg/dL) 0.092 0.410 0.31–0.15 0.004* Phosphate (mg/dL) 0.14 0.344 ‐0.008–0.28 0.063 Sodium (mmol/L) 4.452 0.442 1.402–7.501 0.005* Potassium (mmol/L) 0.136 0.428 0.039–0.23 0.007* Chloride (mmol/L) 0.019 0.080 ‐0.062–0.1 0.640 ALT (U/L) 2.128 0.206 ‐1.633–5.88 0.257 ALP (U/L) ‐3.022 ‐0.097 ‐14.429–8.38 0.593 Systolic blood pressure (mmHg) 10.912 0.575 3.666–18.15 0.005* USG 0.033 0.448 0.013–0.05 0.002* Blood osmolarity (mOsm/kg) 9.59 0.441 2.992–16.18 0.006* UPC 0.153 0.363 0.014–0.29 0.032* ALT, Alanine aminotransferase; ALP, Alkaline phosphatase; BUN, Blood urine nitrogen; USG, Urine‐specific gravity; UPC, Urine protein‐urine creatinine ratio. *p<0.05; **p<0.001.   7 8 ABSTRACT NU32 Plasma copeptin concentrations in cats with naturally occurring chronic kidney diseases Syu‐Yin Lin 1; Wei‐Li Hsu2; Ya‐Jane Lee3; Ji‐Ming Teh4 1Institute of Veterinary Clinical Science, National Taiwan University; 2National Chung Hsing University; 3Institute of Veterinary Clinical Science, School of Veterinary Medicine, National Taiwan University Veterinary Hospital; 4National Taiwan University Arginine vasopressin (AVP) has been reported to exert proproteinuric effects and cause renal function decline in human medicine. And, thus, the elevated levels of vasopressin could potentially serve as a prognostic marker for chronic kidney disease (CKD). It has been demonstrated that vasopressin is negatively associated with estimated glomerular filtration rate (eGFR), and with the development of CKD in both animal and human models via activation of V2 receptors in collecting ducts. However, the small molecular size and unstable characteristic of AVP made the measurement unreliable and that limits its application in clinical practice. The C‐terminal glycopeptide, also called copeptin, is produced in an equimolar ratio (1:1) along with AVP as the result of the cleavage of the precursor of AVP prohormone in hypothalamus. Compared to vasopressin, quantification of copeptin is relatively easier due to the high stability when measured by sandwich immunoassay. Thus, copeptin acts as a surrogate marker that reflects the level of AVP release in many human clinical studies. Positive associations between plasma copeptin and renal function decline as well as proteinuria have been shown in human with CKD. However, the research of plasma copeptin and renal diseases in small animal practice is lacking. Thus, the aims of this study were several folds to investigate: (1) whether the increment of plasma copeptin concentration is proportional to renal function in cases with chronic kidney disease (CKD), (2) whether the concentration of plasma copeptin can be used to predict the risk of renal function decline, and (3) whether plasma copeptin concentration is relative to proteinuria. All cases were collected from National Taiwan University Veterinary Hospital. Healthy control group were the cases with no clinical signs related to CKD and with normal reference values of BUN, creatinine and hematological examination as well as urinalysis. The cats with plasma creatinine level ≥ 1.6 mg/dL and with one of the following conditions including a history of clinical signs (such as polyuria and polydipsia), an abnormal urinalysis (urine‐specific gravity <1.030 or proteinuria [UPC >0.5]), abnormal radiology examination (such as small, irregular kidneys or decreased corticomedullary distinction) for at least 3 months were enrolled as CKD cats. However, the cases with one of the following problems were excluded, including abnormal serum total thyroxine concentration, any lower urinary tract disease and any symptoms other than renal diseases such as liver, heart, infectious and/or neoplastic disease. The CKD cats were further classified into different groups based on International Renal Interest Society (IRIS) staging criteria. And CKD cats with an acute increment of plasma creatinine concentration above 0.5 mg/dL within 14 days would be separated and defined as acute‐on‐chronic injury group (ACKI). A total of seventy cats were enrolled into: 1. healthy control group (n = 7); 2. IRIS Stage 2 group (n = 21); 3. IRIS Stage 3 group (n = 25); 4. IRIS Stage 4 group (n = 10); and 5. ACKI group (n = 6). The definition of CKD progression was an increment of plasma creatine concentration above 0.5 mg/dL within 90 days. Plasma copeptin concentrations were determined from the averaged results of duplicate plates by a commercial quantitative sandwich ELISA kit. Statistically significant difference of plasma copeptin concentration was neither among the control group, CKD and ACKI groups (medians and interquartile range [IQR]: 4.028 [3.966–5.063], 4.039 [3.522–5.615], 4.575 [3.053–5.758], 4.914 [3.472–6.913] and 5.12 [3.958–7.668] pmol/L, respectively), nor among the different stages of CKD. While age (p = 0.002), RBC (p < 0.001), plasma hemoglobin (p < 0.001), BUN (p < 0.001), creatinine (p < 0.001), phosphate (p < 0.001) concentration, value of hematocrit (p < 0.001), urine‐specific gravity (USG) (p < 0.001) and urine protein to creatinine ratio (UPC) (p = 0.001) had significant differences among groups (Table 1). However, in linear regression analysis, plasma copeptin concentrations were significantly decreased with the increment of creatinine (p = 0.014), phosphate (p = 0.024) concentration and urine protein‐to‐creatinine ratio (UPC) (p = 0.007) (Table 2). Furthermore, logistic regression analysis showed that plasma copeptin concentration was not significantly correlated with the progression in feline CKD. In conclusion, plasma copeptin concentrations can be correlated with plasma creatinine, phosphorus and proteinuria in feline CKD, despite without significant increase/decrease in cats with CKD or ACKI. Moreover, our findings implied that plasma copeptin might not be associated with the progression of feline CKD. Table 1. Clinical characteristics and biochemical parameters in control group, IRIS CKD stages 2 ~ 4 and acute‐on‐chronic kidney injury groups Control IRIS CKD Stage 2 IRIS CKD Stage 3 IRIS CKD Stage 4 Acute on chronickidney injury p value Parameters Median (IQR) n Median (IQR) n Median (IQR) n Median (IQR) n Median (IQR) n Copeptin (pmol/L) 4.03 (3.97, 5.06) 7 4.04 (3.52, 5.61) 21 4.56 (3.05, 5.76) 25 4.91 (3.47, 6.91) 10 5.12 (3.96, 7.67) 6 0.656 Age 2.00a,b (1.00,11.00) 7 9.50a (7.75,13.00) 21 13.00a,b (12.05, 12.65) 25 12.85a,b (5.53,16.85) 10 14.75b (13.85, 17.13) 6 0.002* RBC (106/μL) 9.87c (7.69, 10.18) 5 8.47b,c (7.07, 9.03) 21 7.75a,b,c (6.51, 8.66) 20 5.57a (4.44, 6.62) 10 5.60a,b (4.46, 6.15) 5 <0.001** Hemoglobin (g/dL) 14.90a,b (12.90, 15.40) 5 14.00a,c (12.20, 14.85) 21 12.25a,b,c (10.23, 13.10) 20 9.70b,d (6.65, 11.25) 10 8.80c,d (8.00, 9.50) 5 <0.001** Hematocrit (%) 43.10c (37.00–44.60) 5 39.60a,c (34.00, 41.80) 21 35.10a,b,c (26.83, 37.30) 20 27.90b (19.35, 30.83) 10 24.70a,b (21.25, 27.60) 5 <0.001** WBC (/μL) 8100 (5300–12 050) 5 7000 (5750–9100) 21 8800 (7025, 11 325) 20 13100 (10050, 17750) 10 12 500 (8450, 17 500) 5 0.009 BUN (mg/dL) 20.00a,b (19.00, 24.25) 7 28.00a (21.50, 34.50) 20 56.00b,d (39.00, 64.00) 25 87.50c (74.50, 120.75) 10 120.50c,d (62.00, 233.25) 6 <0.001** Creatinine (mg/dL) 1.70a (1.60, 1.90) 7 2.10a (1.80,2.45) 21 3.70b (3.20,4.40) 25 6.30b (5.48, 7.73) 10 7.60b (5.00, 18.18) 6 <0.001** Glucose (mg/dL) 123.50 (105.00, 150.25) 14 116.00 (100.00, 127.50) 9 120.50 (107.75, 163.00) 6 148.00 (134.00, −) 3 0.109 Sodium (mmoL/L) 153.60 (152.30, 154.70) 19 155.00 (153.90, 156.15) 22 153.20 (152.20, 155.85) 10 154.30 (151.40, 161.53) 6 0.077 Potassium(mmol/L) 3.86 (3.56, 4.27) 19 3.95 (3.72, 4.20) 22 3.83 (3.52, 4.14) 10 4.24 (3.55, 4.84) 6 0.420 Chloride(mmol/L) 116.80 (113.10, 118.10) 19 117.55 (116.45, 119.90) 22 115.30 (114.10, 118.95) 10 119.00 (117.43, 124.00) 6 0.051 Phosphate (mg/dL) 4.75a,b (4.63, 4.80) 4 3.90a (3.60, 4.20) 19 4.50a (3.85, 5.40) 21 9.35b (7.10, 10.53) 10 14.25b (8.80, 19.70) 6 <0.001** Plasma osmolality (mOsm/L H2O) 311.60 (308.05, 313.41) 19 314.08 (311.68, 316.33) 22 310.67 (308.33, 315.47) 10 312.4 (306.08, 327.99) 6 0.081 Systolic arterial pressure (mm Hg) 138.00 (128.00, 142.00) 12 151.00 (137.00, 170.50) 17 139.00 (130.00, 150.00) 7 133.00 (118.50, 144.50) 4 0.043* USG 1.056a (1.045, 1.067) 7 1.014b (1.010, 1.030) 13 1.011b (1.009, 1.013) 18 1.010b (1.007, 1.012) 7 1.009a,b (1.008, −) 3 <0.001** UPC 0.01a (0.01, 1.00) 7 0.14a (0.09, 0.20) 8 0.23a,b (0.12, 0.51) 11 0.69b (0.52, 1.08) 5 1.05a,b (0.37, −) 3 0.001* 1. The parameters were analyzed by Kruskal‐Wallis test and Dunn test. The values were shown with median and IQR in brackets. 2. The different superscripts (a, b, c, d) indicated various significant differences. 3. ALKP, Alkaline phosphatase; BUN, Blood urine nitrogen; UPC, Urine protein‐urine creatinine ratio; USG, Urine specific gravity. 4. *p<0.05; **p<0.001.   9 10 11 12 Table 2. Simple linear regression analysis of different parameters and plasma copeptin in all cases Parameters B value Adjustment β 95% CI for B value p value Age (year‐old) 0.083 0.053 −0.085–0.12 0.664 Hematocrit (%) 0.020 0.008 −0.656–0.695 0.008 RBC (106/μL) 0.014 0.025–0.132 −0.160 0.846 Hemoglobin (g/dL) 0.014 0.015 −0.224–0.252 0.909 WBC (/μL) −230.733 −0.114 −755.164–293.699 0.382 Albumin (g/dL) −0.002 −0.019 −0.036–0.031 0.899 Glucose (mg/dL) −0.393 −0.058 2.895–2.108 0.751 BUN (mg/dL) 2.289 0.164 −1.123–5.702 0.185 Creatinine (mg/dL) 0.292 0.296 0.062–0.522 0.014* Ionized calcium (mmol/L) −0.038 −0.468 −0.086–0.010 0.107 Total calcium (mg/dL) 0.083 0.936 −0.012–0.178 0.064 Phosphate (mg/dL) 0.349 0.291 0.048–0.650 0.024* Total calcium x phosphate 1.566 0.686 −3.491–6.624 0.314 Sodium (mmol/L) 0.021 0.023 −0.230–0.273 0.866 Potassium (mmol/L) 0.032 0.192 −0.012–0.076 0.152 Chloride (mmol/L) 0.148 0.127 −0.163–0.460 0.345 AST (U/L) 1.063 0.101 −3.587–5.714 0.640 ALT (U/L) −0.668 −0.008 −32.975–31.638 0.966 ALP (U/L) −1.310 −0.216 −4.070–1.451 0.334 Systolic arterial pressure (mm Hg) 3.023 0.268 −0.549–6.595 0.095 USG −0.001 −0.120 −0.003–0.001 0.416 Plasma osmolarity (mOsm/kg) 0.074 0.039 −0.436–0.585 0.771 UPC 0.089 0.031 0.026–0.152 0.007* 1. AST, aspartate aminotransferase; ALT, Alanine aminotransferase; ALP, Alkaline phosphatase; BUN, Blood urine nitrogen; USG, Urine specific gravity; UPC, Urine protein‐urine creatinine ratio. 2. *p<0.05; **p< 0.001.   13 14 ABSTRACT NU33 Evaluation of ultrasonographic and biochemical parameters to predict outcome after treatment of feline ureteral obstructions Elisa P. McEntee 1 ; Allyson Berent1; Kenneth Lamb2; Alex Le Roux1; Chick Weisse1 1The Animal Medical Center; 2Lamb Consulting The background is as follows. To date, no pre‐operative prognostic factors have been clearly identified for cats undergoing renal decompression after a diagnosis of a ureteral obstruction (UO). Frequently, judgment of long‐term outcome is made based on the ultrasonographic appearance of the kidney, but this has not been well substantiated by any clinical data. The objectives are as follows. To determine whether pre‐operative imaging characteristic(s) in cats suffering from a unilateral UO was predictive of renal recovery and long‐term outcome after renal decompression. The animals are 34 cats with unilateral, benign UO. The methods are as follows. Pre‐operative imaging characteristics (including renal pelvis diameter, parenchymal thickness [transverse and sagittal planes], renal length, and pelvic size: overall renal size) and biochemical data were retrospectively evaluated for all cats diagnosed with a unilateral UO treated with a SUB device. All patients were followed between 3 and 6 months post‐operatively to obtain post‐operative baseline biochemical data and had confirmed renal decompression based on SUB device flushing and patency confirmation. The results are as follows. No pre‐operative imaging characteristics or biochemical findings were found to be significantly correlated with long‐term creatinine. The length of the kidney and parenchymal thickness in the sagittal plane were found to be correlated to change in BUN and creatinine with decompression, but not with long‐term renal values or IRIS Stage. The conclusions and clinical importance is as follows. Prediction of long‐term renal recovery based on pre‐operative biochemical data or ultrasound imaging findings should not be made in cats with ureteral obstruction(s) regardless of the severity of renal pelvic dilation (large or small pelvis), kidney size, or thickness of renal parenchyma assessed. ABSTRACT NU34 High‐protein diet does not affect markers of kidney function in cats with asymptomatic hypertrophic cardiomyopathy Yann Quéau 1; Esther Bijsmans1; Elizabeth Bode2; Geoff Culshaw3; Jo Dukes‐McEwan2 ; Jonathan Elliott4; Julie Hamilton‐Elliot2 ; Hannah Hodgkiss‐Geere2 ; Jeremy Laxalde1; Yolanda Martinez Pereira3; Paul Motskula5; Valentina Palermo6; Ingrid van Hoek1 1Royal Canin SAS; 2University of Liverpool; 3University of Edinburgh; 4Royal Veterinary College; University of London; 5Estonian University of Life Sciences; 6Anderson Moores Veterinary Specialists Prevalence of asymptomatic hypertrophic cardiomyopathy (aHCM) and chronic kidney disease (CKD) in cats increases with age. Cardiac and renal function are tightly integrated across species. High protein (HP) and phosphorus diets are associated with worse outcome of CKD, however a HP diet restricted in starch and with omega‐3 fatty acids supplementation showed reverse remodeling effects of primary echocardiographic variables in cats with aHCM (van Hoek et al, ECVIM 2019). The aim of this study was to determine whether feeding a HP diet has deleterious effects on renal health in cats with aHCM. Forty‐four cats with aHCM (ISACHC stage 1b) without signs of kidney disease (aged 5 [1.4–17] years) were included after informed owner‐consent and randomly allocated to diet group HP or low protein (LP) (Table 1), in a prospective, double‐blind, multicenter study. Both dry and moist forms of the two diets were available (Table 1). Owners could opt for feeding only dry, only moist or mixed feeding according to the cat's preference. Serum creatinine, BUN, phosphate, and fibroblast growth factor‐23 (FGF‐23) concentrations were measured in non‐sedated, fasted cats before and after 6 and 12 months of feeding the allocated diet. Two‐way repeated measures ANOVA compared the measured variables with both time (baseline, 6 and 12 months) and group (HP and LP) with a significance level of 5%. Results are expressed as median and range (minimum–maximum). Table 2 shows a significant diet‐time interaction for BUN (p = 0.0013) with significant increase after 6 and 12 months of feeding the HP diet, but no significant change over time for creatinine, phosphate or FGF‐23 in either group, and the small number of cats with serum concentration ≥ upper reference range at each timepoint. There was no evidence that feeding a high protein diet over 12 months has detrimental effects on renal excretory function in cats with aHCM in this study. This paves the way to maximizing the therapeutic potential of dietary manipulation in aHCM, in cats without pre‐existing CKD.   ABSTRACT NU35 16S ribosomal RNA gene amplification of urine from cats with suspected renal dysfunction Kenny Siu 1; Cindy Sotelo1; Stacie Summers2; Jennifer Hawley1; Jesse Buch3; Michael Lappin1 1Colorado State University; 2Oregon State University; 3IDEXX All causes of renal dysfunction in cats have not been ascertained. While some cats with renal diseases are culture positive, the majority are negative. However, it is possible that difficult to culture (Bartonella spp.; Leptospira spp.) or unculturable bacteria could be playing a causative role. Use of 16S rRNA primers to amplify the microbial DNA in biological samples with sequencing used to determine the genus and species is being used more frequently in veterinary medicine. The objectives of this study were to determine the concentrations of DNA in the urine of client owned cats after extraction using a standardized protocol and to determine amplification rates for 16S rRNA genes. Blood and urine from cats with suspected renal dysfunction (urine specific gravity was <1.035 and symmetric dimethylarginine (SDMA) ≥15 μg/dL) from 2 commercial laboratories (California and Massachusetts) were available for study. Urine total DNA had been stored at 80°C until used in this study. The urine samples had been centrifuged at 16,000 g for 30 minutes at 4°C. The supernatant was removed while preserving the urine pellet undisturbed. Five hundred microliters of sterile phosphate buffered solution (PBS) was added to reconstitute and wash the urine pellet by brief vortexing. The PBS‐urine pellet mix was centrifuged for 15 minutes at 21,000 g at room temperature. The supernatant was carefully pipetted off the pellet and the pellet was suspended in 200 μL PBS for DNA extraction using a commercially available kit (QIAamp DNA Mini Kit; Qiagen). The concentrations of double stranded DNA were determined by Qubit (Invitrogen; sensitivity =10 pg/μL to 100 ng/μL) and total nucleic acid concentrations were determined by Nanodrop (ThermoFisher; sensitivity =2 ng/μL). Bacterial DNA was amplified using a previously published real‐time 16S rRNA V4 PCR assay. A convenience sampling of 50 cats with suspected renal dysfunction and white blood cells on urine sediment examination (2–5/HPF; n = 25), hematuria (≥6/HPF) without pyuria (0–1/HPF; n = 18) or proteinuria alone (urine dipstick ≥1+; n = 7) was chosen. The median starting volume of urine for pelleting and DNA extraction was 0.95 ml (range, 0.1–1.0 ml). Nucleic acids were detected by the Nanodrop protocol in 48/50 samples (median, 1.26; range 0.04–11.5 ng/μL). Double‐stranded DNA was detected by the Qubit protocol in 44/50 samples (median, 0.01; range, 0.005–0.034 ng/μL). None of the samples were positive for 16S rRNAV4 gene sequences. Microbial DNA was not amplified from urine samples suggesting a sterile urine environment in this cohort of cats. However, based on the results from the 2 non‐specific nucleic acid quantification techniques, the concentrations of DNA may have been too low for detection of the 16S rRNA gene. False‐negative results could have occurred with the PCR assay used. Future studies should use larger urine volumes, use samples that have not been frozen and thawed which may degrade DNA, and evaluate urine specific extraction techniques with more sensitive PCR assays. ABSTRACT NU36 Expression patterns of Krüppel‐like factors (KLFfs) in renal tissue in felines with kidney dysfunction Selena Tavener 1; Dennis Jewell2; Kiran Panickar3 1Hill's Pet Nutrition, Inc.; 2Kansas State University; 3Hills PNC Krüppel‐like factors (KLFs) are a family of zinc‐finger transcription factors that play an important role in cellular differentiation and proliferation during embryonic development. In addition, KLFs are also involved in key renal physiological processes including podocyte function, mesangial function, renal fibrosis, and tubulointerstitial inflammation. The aim of the present study was to investigate changes in gene expression associated with fibrosis and inflammation in renal tissue of cats with kidney disease or calcium oxalate stone formers (CaOx) from samples obtained at necropsy (end‐of‐life samples). At the time of death the circulating levels of creatinine, symmetric dimethyl arginine (SDMA), as well as blood urea nitrogen, all markers of kidney decline in cats, were significantly higher in cats with renal disease (n = 11) or stone‐forming cats (CaOx, n = 12) when compared to controls (n = 19). Using RNAseq in renal cortex tissue, we found a significant decrease in KLF15 in cats with kidney disease (−1.99 fold, p < 0.001) and CaOx (−1.89, p < 0.001) when compared to controls. Given that KLF15 can attenuate fibrosis by inhibiting the actions of TGF‐β, a key regulator of fibrosis, our results indicate that a lower level of KLF15 in kidney disease and CaOx may be contributing to renal fibrosis in cats. Also, as KLF15 is a regulator of podocyte differentiation and is protective against podocyte injury, its decline in cats with kidney dysfunction indicates a potential damage to podocytes and thus the glomerular filtration barrier. Consistent with this there was a decline in podocin and nephrin, markers of podocytes, compared to controls. KLF9 was also decreased in kidney disease (−1.35 fold; ns) and it was significantly decreased in CaOx (−1.59; p < 0.05). Whether KLF9 plays an important role in maintaining glomerular barrier function is not known, but its role in maintaining intestinal barrier has been reported. A decline in KLF5 was also found in both groups compared to control (both ns). In contrast, KLF6 and KLF10 were modestly increased in both groups compared to controls (both >1.50; ns). KLF6 has been reported to be increased in renal fibrosis. There was little to no change in other KLFs detected including KLF3, KLF4, KLF7, KLF11, and KLF12, in either group compared to controls. Our results indicate the different expression levels of KLFs in renal tissue in cats with kidney disease and CaOx. Taken together, a decline in KLF15, KLF9, and an increase in KLF6 may be important indicators of renal fibrosis and glomerular filtration dysfunction. ABSTRACT NU37 Intra‐individual variability of urinary calcium to creatinine and oxalate to creatinine ratios in cats Esther Bijsmans; Gwendoline Chaix; Laurence le Verger; Vincent Biourge; Yann Quéau Royal Canin Spot urinary calcium‐to‐creatinine ratio (UCa:Crea) and oxalate‐to‐creatinine ratio (UOx:Crea) have been proposed as measures of calcium oxalate crystallization risk, though few studies have researched normal values in cats. Dijcker (2013) reported (median[range]) UCa:Crea: 0.08[0.04–0.31] and UOx:Crea: 0.05[0.03–0.06] mmol/mmol in 3 stone‐formers. This study aimed to determine the intra‐individual variability of UCa:Crea and UOx:Crea in healthy cats, with comparison to those stone‐forming cats. A base dry extruded diet (Diet A, 0.7% K+) was supplemented with potassium chloride (Diet B, 1.7% K+), to achieve greater urine dilution. Eighteen healthy adult cats were fed each diet for 7 days, followed by 3 days of urine collection. Each micturition was collected. Urinary ions were measured using ionic chromatography. The coefficient of variation (CV) for urinary calcium and creatinine was <5%, and <10% for oxalate. Data was log‐transformed as needed. Mixed effect models assessed the effect of diet and micturition on UCa:Crea and UOx:Crea, using animal as random term. Intra‐individual coefficient of variations (ICV) are reported in the table below. There was no significant difference between diets or micturitions for both UCa:Crea and UOx:Crea (p > 0.10 for all), but variability was seen. In conclusion, UCa:Crea showed important intra‐individual variability between micturitions, but UOx:Crea varied less. Both showed overlap with values reported in stone‐formers. Assessment of clinical applicability requires greater patient numbers and determination of discriminating power.   ABSTRACT NU38 Intra‐individual variability of urinary calcium to creatinine and oxalate to creatinine ratios in dogs Esther Bijsmans; Gwendoline Chaix; Laurence le Verger; Yann Quéau; Vincent Biourge Royal Canin Spot urinary calcium‐to‐creatinine ratio (UCa:Crea) and oxalate‐to‐creatinine ratio (UOx:Crea) have been proposed as monitoring indexes for crystallization risk in dogs with calcium oxalate urolithiasis, although only UCa:Crea is reported to be increased in stone‐forming dogs. This study aimed to determine the intra‐individual variability of UCa:Crea and UOx:Crea, and compare values to those described in stone‐formers. Two dry extruded maintenance diets (A & B) with different macronutrient profiles were fed to 6 healthy adult Miniature Schnauzers (MS) for 7 days, followed by 3 days of urine collection. Each micturition was collected. Urinary ions were measured using ionic chromatography. Coefficient of variation (CV) for urinary calcium and creatinine was <5%, and <10% for oxalate. Data was log‐transformed as needed. Mixed effect models investigated the effect of diet and micturition on UCa:Crea and UOx:Crea, using animal as random term. Intra‐individual coefficient of variations (ICV) are reported below. No significant difference was found between diets or micturitions for UCa:Crea and UOx:Crea (p > 0.05). Seventeen (24%) urine samples had higher UCa:Crea than stone‐forming MS (0.19 mmol/mmol) (Furrow, 2017). In conclusion, UCa:Crea showed important intra‐individual variability in spot urine samples, with values above those reported in stone‐forming MS. Its use as a risk index or for monitoring should be applied with caution. Urinary Ox:Crea had lower ICV but its relevance remains to be determined. ABSTRACT NU39 Tetrasodium EDTA: An efficient chemolytic agent for dissolution of feline and canine uroliths in vitro Alice Defarges 1; Allyson Berent2; Gabrielle Monteith3; Scott Weese4; Hayden Marshall5 1University of Guelph; 2Head of Interventional Endoscopy, Animal Medical Center; 3Statistician Technician, University of Guelph; 4Full Professor, University of Guelph; 5DVM student, University of Guelph The objective was to determine if tetrasodium EDTA (tEDTA) dissolves feline and canine calcium oxalate (FeOx, K9Ox), and struvite (FeSt, K9St) uroliths in vitro. 120 (3–5 mm) analyzed cystic FeOx, K9COx, FeSt, K9St uroliths were obtained. Sixty uroliths were soaked in artificial urine, weighed daily and lavaged twice daily with 2% tEDTA (10 treated per type), or artificial urine (5 controls per type) for 5 consecutive days per week for 2 weeks. The same experiments were performed using 1% tEDTA. A general linear model for repeated measures controlling for each initial urolith weight was used to test for significant differences. p < 0.05 was considered significant. All 2% tEDTA treated uroliths weight decreased significantly compared to controls by day 1. K9Ox, FeSt weight decreased significantly by day 5, K9St and FeOx weight by day 12 when lavaged with 1% tEDTA (p < 0.001). 1 and 2% tEDTA dissolve 3–5 mm K9St, FeSt, K9Ox and FeOx uroliths in vitro, which supports the potential for tEDTA to be evaluated as a topical chemolytic in vivo. Percentage of treated and control uroliths completely dissolved at different time points (days 5, 7 and 10) during the experiments involving 1 and 2% tEDTA and artificial urine Group Percentage of uroliths dissolved at Day 5 Day 7 Day 10 tEDTA % 1 2 1 2 1 2 K9Ox Treated 0 40 0 40 0 100 Control 0 0 0 0 0 0 FeOx Treated 0 30 0 30 0 100 Control 0 0 0 0 0 0 K9St Treated 0 20 0 20 10 100 Control 0 0 0 0 0 0 FeSt Treated 0 100 0 100 100 100 Control 0 0 0 0 0 0   ABSTRACT NU40 Investigation on urinary and serum alpha klotho in dogs with chronic kidney disease Dasol Park 1; Hongjae Yi1; Jong‐Bok Lee2; Kyu‐Pil Lee1; Kunho Song1; Kyoung won Seo1 1College of Veterinary Medicine, Chungnam National University; 2 Yonam College As a co‐receptor for FGF‐23, klotho plays a pivotal role in phosphate metabolism. The kidney is not only known to be a main source of soluble alpha klotho, but also a principal regulator for maintaining its concentration. The objective of this study is to measure serum and urinary alpha klotho in CKD dogs and to identify their association with IRIS CKD stages and other parameters known to be associated with CKD. Dogs were diagnosed with CKD and classified into different stages using IRIS guidelines. Control group was composed of healthy dogs without any clinical signs. Serum and urinary alpha klotho were measured by a commercially available canine specific ELISA kit. Calculated urine klotho to creatinine ratio (UrKl/Cr) was used to minimize the effect of USG. UrKl/Cr was significantly lower in stage 3 dogs compared to that of control group (p = 0.001; Figure 1). UrKl/Cr of stages 3 and 4 was significantly decreased compared to that of stages 1 and 2 (p < 0.001). UrKl/Cr was negatively correlated with sSDMA, BUN, creatinine and phosphorus concentration (Figure 2). UrKl/Cr was decreased in dogs with advanced CKD. In addition, it was negatively correlated to parameters related to kidney function or damage. Therefore, it supports the possibility that klotho has a potential role in the pathogenesis of CKD and its clinical consequences in dogs. Serum klotho was not significantly related to IRIS CKD stages or other parameters tested in this study.   ABSTRACT NM01 Comparison of essential nutrients in plant‐based pet foods with nutrient requirements of dogs and cats Sarah A. S. Dodd 1; Anna‐Kate Shoveller1; David Ma1; Andrea Fascetti2; Zhenshou Yu2; Adronie Verbrugghe1 1University of Guelph; 2University of California, Davis Some pet owners choose to feed plant‐based diets to their facultative carnivorous dog or obligate carnivorous cat, either as part of (7.9% of pet owners) or the complete (1.3% of pet owners) diet. Previous evaluations of essential nutrient content of these diets have been limited, thus the objective of this study was to investigate the dietary content of multiple essential nutrients in plant‐based diets. Proximate analyses, amino acids, fatty acids, minerals (not including selenium and iodine), and vitamins A, B12 and D3 were measured in accordance with AOAC methods in single samples of all plant‐based pet foods commercially available in Canada at the time the study was conducted. Depending on analytical variance, analyses were performed in singlet (proximates, minerals, vitamins), duplicate (fatty acids), or triplicate (amino acids). Twenty‐six (18 dog, 5 cat, 3 both; 18 dry, 8 wet) products were included. All foods produced in the USA (11) and 2 of 4 foods produced in Canada had an AAFCO adequacy statement on their label. No foods produced in Europe (11) had an AAFCO statement on their label, though indications of completeness and/or balance in accordance with FEDIAF were present. Essential nutrient analyses of all diets were compared to NRC nutrient requirements for maintenance or growth, for their intended species and life‐stage as labeled. Twenty percent (4 of 20) of canine and none (0 of 8) of feline adult or all life stage diets met all requirements for adult maintenance. No canine (0 of 7) or feline (0 of 5) growth or all life stage diets met all requirements for growth. One canine growth diet met requirements for adult maintenance. Estimates of nutrient density were corrected to account for inter‐laboratory variation and those failing to comply with recommended allowance are presented in Table 1. Most (22/26, 85%) diets failed to meet the nutrient profile for which they were intended. Of greatest concern were failures to meet the calcium, phosphorus and vitamin D3 requirements of growing dogs and cats, and sulfur amino acid requirements of both growing and adult dogs and cats. Formulation of plant‐based diets for pets must focus on inclusion of these essential nutrients to meet the requirements of the animals for which they are intended to be fed, and animals being fed plant‐based diets should be closely monitored for signs of malnutrition, particularly associated with sulfur amino acid and bone metabolism, such as skeletal deformities, abnormal growth, and failure to thrive. Table 1. Range of percent (%) of recommended allowance met for species and lifestage intended. Bolded values represent percentages below or above recommended allowances. Zero values indicate nutrients below detection levels, which were below the minimum requirement Nutrient Canine maintenance Canine growth <14 weeks old Canine growth >14 weeks old Feline maintenance Feline growth Methionine 65–398 129–375 173–505 260–865* 106–334 Methionine + cystine 39–276 83–256 110–338 177–566 67–219 Taurine ND ND ND 77–189 84–211 Total fat 155–457 100–288 100–288 95–162 95–162 Linoleic acid 131–1360** 131–894 + 131–894 + 255–1936 ++ 603–1936 ++ Arachidonic acid ND ND ND 108–276 32–83 EPA+DHA 0–83 0–33 0–33 0–55 0–55 Calcium 96–473 39–182 39–182 160–490 58–178 Phosphorus 177–496 63–112 63–112 242–412 81–149 Sodium 54–1603 123–315 123–315 251–1062 225–516 Chloride 73–2942 78–485 78–485 387–1524 87 ‐163 Zinc 74–399 93–359 93–359 120–485 119–479 Vitamin A 29–459 84–459 84–459 75–696 75–696 Cholecalciferol 0–450 0–564 0–564 0–446 0–693 Vitamin B12 0–19735 0–19735 0–19735 0–31862 0–31862 ND=recommended allowance not determined. *Exceeds safe upper limit (SUL) by 13%; **Exceeds SUL by 130%; +Exceeds SUL by 51%; ++Exceeds SUL by 94%.   15 16 ABSTRACT NM02 Evaluation of nutrient content and caloric density in commercially available foods formulated for senior cats Stacie Summers 1; Jonathan Stockman2; Anais Sanchez Rodriguez2; Lei Zhang2 1Oregon State University; 2Colorado State University Despite the lack of determined nutritional guidelines for senior cats, multiple commercial cat food products that are marketed for senior cats are available to owners. Although these products adhere to the Association of American Feed Control Officials (AAFCO) adult guidelines, the variability in the protein, fat, caloric density, and mineral content of these diets are unknown. The aim of the study was to measure the caloric density and caloric distribution of protein, fat, and select minerals in commercially available foods labeled for senior cats (≥7 years) and compare results to adult cat foods. Thirty‐one senior cat foods and 59 adult cat foods (both canned and dry) were purchased from pet stores. Two lots were available and purchased for 26/31 senior cat foods. Food analysis was performed using official methods of the Association of Official Agricultural Chemists International. All food samples were analyzed for complete proximate (moisture, crude protein, crude fat, crude fiber, ash) and select minerals (phosphorus, calcium, potassium, sodium). Measured crude protein, fat, mineral percentages were converted to g/1,000 kcal metabolizable energy (ME) using modified Atwater factors for protein, fat, and carbohydrate to allow for comparisons among study foods. Caloric density was calculated based on dry weight. Descriptive statistics are presented as median and range. An unpaired t test or Mann‐Whitney test and one‐way ANOVA or Kruskal‐Wallis test was used to compare caloric density and mineral contents between groups. A p‐value<0.05 was considered significant. The average of the 2 lots were used for statistical analysis. All senior cat foods were formulated to meet the AAFCO nutrient profile for adult maintenance. For the adult cat foods, 31 diets had adequacy statements for AAFCO nutrient profile for adult maintenance, and 28 diets had statements for all life stages. No significant difference in the analyzed caloric density or mineral content of senior cat foods was found when compared to adult cat foods and cat foods formulated for all life stages. In conclusion, senior cat foods had highly variable caloric densities and mineral content. Caution should be taken when making broad recommendations for the use of commercially available senior foods in cats. Adult foods n = 59 Senior foods n = 31 p‐value Caloric density kcal/100 grams 413 (359–635) 406 (337–505) 0.204 Protein g/1,000 kcal ME 100 (50–173) 94 (77–139) 0.147 Fat g/1,000 kcal ME 48 (26–90) 46 (33–79) 0.452 Phosphorus g/1,000 kcal ME 3.1 (0.9–5.8) 3.2 (1.5–4.4) 0.636 Calcium g/1,000 kcal ME 3.9 (0.8–8.7) 3.7 (1.9–5.7) 0.768 Calcium:phosphorus ratio 1.3 (0.8–1.7) 1.3 (0.9–1.6) 0.605 Magnesium g/1,000 kcal ME 0.27 (0.06–0.54) 0.28 (0.12–0.56) 0.591 Potassium g/1,000 kcal ME 2.2 (1.2–3.9) 2.3 (1.7–3.6) 0.131 Sodium g/1,000 kcal ME 1.1 (0.5–3.9) 1.1 (0.7–2.7) 0.913   ABSTRACT NM03 Canine obesity knowledge among Brazilian owner's is associated to overweight risk in dogs Mariana Y. Porsani; Fabio Teixeira; Vinicius Oliveira; Gabriel dos Santos; Tatiane Pooli; Pamela Vasconcerva; Marcio Brunetto School of Veterinary Medicine and Animal Science, USP This study aimed to assess the canine obesity knowledge and body condition score (BCS) perception among dog owners in Brazil. A face‐to‐face questionnaire was applied to owners (n = 926). The dog's BCS (1 to 9) were evaluated by veterinary nutritionists and owners. The information was associated with the chi‐square test, and the odds ratio test (OR). Dogs (n = 926) were divided into two groups: ideal weight (IW) (BCS 4 and 5/9) = 51.8% (480/926); and overweight (OvW) (BCS ≥6/9) 48.2% (446/926), equally, owners were classified according to their dog's group: 62.5% of owners of IW dogs (300/480) and 74.4% of OvW dogs (332/446) believed that snacks are related to their dog's weight gain, this answer was associated with BCS group (p < 0.001) and resulted in OR 1.747 to dogs be overweight. Acknowledge that obesity is a health problem was reported by 97.1% of IW owners and 80.9% OvW, it was associated with BCS (p < 0.001) and resulted in OR 2.06 of being overweight. The majority (97.1%) of owners would be willing to enroll their dog's into a weight loss program if recommended by a veterinarian, however, 50.5% of OvW and 63.6% of IW underestimate their dog's BCS (p < 0.001). Belief that supplements are necessary for weight loss resulted in OR 1.537 and it was associated with overweight dogs. The owner's knowledge regarding obesity was associated with a higher risk of dogs being overweight. ABSTRACT OT01 The dog aging project study population—An initial look at the members of the pack Lucy Chou 1; Audrey Ruple2; Katie Tolbert1; Katee Creevy1; Matt Dunbar3; Matt Kaeberlein3; Daniel Promislow3; Dog Aging Project Team1 1Texas A&M University; 2University of Purdue; 3University of Washington Age is the single greatest risk factor for many diseases in humans, yet most of what we know about the biology of aging we have learned from laboratory‐based studies of short‐lived model organisms like yeast, worms, mice, and flies. This work has advanced our knowledge of aging in meaningful ways, but we still have gaps in our understanding of the genetic and environmental determinants of healthy aging. Aging in dogs resembles that of humans and they share age as a risk for developing many of the same diseases as humans. Dogs also share a tremendous amount of our genetics and they share our daily environment—including our climate, infectious disease exposure, and chemical exposures. Thus, studying aging in dogs may help us to understand aging in both dogs and humans. We have launched a large‐scale longitudinal study of aging in dogs that will utilize a team of citizen scientists to help us learn more about aging in companion dogs. All dog owners in the United States have the opportunity to nominate their dog to this project. The initial call for nominations was overwhelmingly successful, with over 78,000 dogs nominated to the project in less than two months. Most of the dogs included in this initial nomination lived in single dog households (45,976/78,489), but 12.8% of the dogs live in households with three or more dogs. The vast majority of the dogs were indoor dogs, with 99.0% of nominated dogs sleeping in the house at night (77,703/78,489) and many of these dogs were reported to sleep in the owner's room (77.3%). The majority of the dogs nominated were seen by their veterinarian at least one time per year (75,245/78,489), but a small number of dogs were reported to have never been seen by a veterinarian (279/78489). The population of nominated dogs was split evenly between mixed (50.4%) and pure breed dogs (49.6%). The most common pure breeds of dogs reported were, in order of descending frequency, Labrador retriever (4,836), Golden retriever (4,023), German shepherd dog (1,887), Dachshund (1,186), and Australian shepherd (1,132). There were slightly more male dogs (51.7%) nominated than female dogs, but the majority of dogs, regardless of sex, were neutered. The average age of nominated dogs was 6.6 years, with the oldest dogs nominated being 24 years of age. Dogs were nominated from across the United States in similar proportion to the population of people in each state (Figure 1). This initial group of dogs nominated to the Dog Aging Project represent a diversity of breeds and ages and includes both sterilized and intact dogs of both sexes. Also, the geographic diversity of this population is representative of that which we see in our human population. Thus, the Dog Aging Project population will be useful in helping us to better understand the genetic and environmental determinants of healthy aging in dogs and we will be able to make inferences about human populations as well.   ABSTRACT OT02 Scoring of erythema, excoriation, and lichenification severity in canine atopic dermatitis using deep learning Jung‐Hyun Kim 1; Suk‐Jun Lee2; Sung‐Sik Yoon2; Yoon‐Mi Kim1; Young‐Rok Kim1; Sang‐Won Kim1 1Konkuk University; 2Kwangwoon University The background is as follows. Canine Atopic Dermatitis Extent and Severity Index (CADESI) is the most commonly used for evaluation of the severity of atopic dermatitis in dogs. It requires training and validating of evaluators, and it is still challenging to score the severity of canine atopic dermatitis objectively with CADESI score. Therefore, a new approach to assess the severity of canine atopic dermatitis is needed to solve the problems of unsupervised diagnostic methods and improve the quality of veterinary medical services. Automated standardization of erythema, excoriation, and lichenification severity with clinical images has not been investigated yet. It is expected to contribute to the practical use in veterinary medicine. The objectives are as follows. The aim of this study was to determine whether the deep learning using convolutional neural networks (CNNs) could assess erythema, excoriation, and lichenification severity at the level of competence comparable to veterinarians' scoring. The methods are as follows. We made a standard dataset of 2,000 clinical images of dogs showing atopic dermatitis. These images were scored 0 to 3 for each sign by three veterinarians. We trained four CNNs (ResNet V1, ResNet V2, GoogLnet, and VGG‐Net) with the image dataset, and then examined which CNNs was most suitable for erythema, excoriation, and lichenification scoring. In this process, we use 200 cropped images for erythema, and 84 cropped images for excoriation scoring, and 156 cropped images for lichenification scoring. The results are as follows. For erythema, ResNet V1 152 showed the highest accuracy (74.38%), and ResNet V1 50 was the best (80.88%) for excoriation. In case of lichenification, ResNet V1 50, 101, and 152 showed the best performance with accuracy (90.32%). The conclusion and clinical relevance are as follows. These results suggest some CNNs have a performance capacity for erythema, excoriation and lichenification scoring at the level of competence comparable to veterinarians. Finally, deep learning for scoring severity of erythema, excoriation, and lichenification could be a useful tool for the evaluation of canine atopic dermatitis. Further research is needed to improve the diagnostic accuracy, and if scoring system using CNNs is applied to veterinary medical devices, it may be useful for routine veterinary clinical practice. ABSTRACT P01 An in vitro evaluation of intravenous lipid emulsion on three common canine toxicants Emery A. Jones 1; Stuart Walton1; Jennifer Davis2; James Colee3 1College of Veterinary Medicine, University of Florida; 2Virginia‐Maryland College of Veterinary Medicine; 3University of Florida Intravenous lipid emulsion (ILE) therapy is a novel therapy recommended for lipophilic and local anesthetic drug toxicities. There are several proposed mechanisms of action for ILE therapy including the lipid sink theory, an increased mitochondrial recovery, and a direct ionotropic activity. Previous reports of therapeutic success of ILE therapy relied on resolution of clinical signs as opposed to documented decreases in drug concentration levels. The primary aim of this study was to determine whether ILE therapy significantly reduces the concentration of free drug (baclofen, ibuprofen, and bromethalin) in canine whole blood over time. The secondary aim was to determine the percent reduction in drug (baclofen, ibuprofen, and bromethalin) concentration over time with the use of ILE therapy to simulate the direct lipid effects in the lipid sink theory. Seven units (500 ml) of 1.1 negative canine blood were divided into 125 ml bags and randomly assigned to one of 3 (ibuprofen, baclofen or bromethalin) treatment groups or 4 control groups (a positive control for each study group and a negative control group). A measured amount of injectable ibuprofen (200 mg/kg), baclofen (8 mg/kg), or bromethalin (3 mg/kg) was apportioned into each smaller unit of canine whole blood and incubated for 30 minutes at 38.5°C. A known amount of ILE (12.4 ml, Intralipid®) was added to each sample and the solution was vortexed at 215 rpm for 15 minutes at 37°C (98.6 °F). Whole blood was sampled at designated time points (0, 15, 30, 60, 180, 360 min), centrifuged, and separated into plasma and RBC fractions. Plasma samples were ultracentrifugation at 22,000 g at 37°C for 10 minutes to separate lipid rich and lipid poor fractions. All samples were stored at −80°C until prior to analysis and allowed to thaw at room temperature. Samples were subjected to protein precipitation followed by mixing, vortexing for 30 seconds and centrifugation at 16,100 x g for 10 minutes. Ultra‐high‐performance liquid chromatography with tandem mass spectrometry was used to determine the concentrations of ibuprofen, baclofen, bromethalin, desmethylbromethalin (bromethalin metabolite) in the lipid poor sample of canine plasma. Ultra‐high‐performance liquid chromatography was also used to determine ibuprofen concentration in red blood cells. Change in concentration of drug with the addition of ILE over time was measured and compared to the positive control to assess the binding ability of ILE. Collected data was analyzed using the Tukey‐Kramer analysis, least squares mean estimates, and the GLIMMIX procedure. The total change in concentration of each drug was compared to the change in concentration of the control. A significant (p value 0.0006) change in concentration of total drug was only established for bromethalin with a percent reduction of 86%. ILE significantly reduced both the overall bromethalin concentration and bromethalian concentration at all time points when compared to the positive controls. Neither baclofen, ibuprofen, nor desmethylbromethalin had significant changes in concentration. In this single compartment in vitro study, ILE therapy may be efficacious for the treatment of bromethalin toxicosis. Furthermore, measurement of desmethylbromethalin, a bromethalin metabolite, did not demonstrate a significant change in concentration, suggesting that the decrease in bromethalin was not due to the conversion of bromethalin to its metabolites. However, it is possible that bromethalin is being converted to other unmeasurable metabolites as opposed to a true response to ILE therapy. These initial results are suggestive that the ILE lipid sink may be beneficial in reducing free bromethalin in canine serum. In the case of a simulated ibuprofen or baclofen overdose, treatment with ILE did not demonstrate a significant decrease in drug concentration. As a single compartment study, this study does not evaluate other proposed mechanisms of action of ILE therapy, and therefore ILE therapy may have other means of significantly decreasing the concentration of drugs such as bromethalin, baclofen, and ibuprofen in cases of toxicosis. Based on the results from this study, the lipid sink mechanism is only responsible for decreases in drug concentration in bromethalin toxicosis. Further in vivo study in naturally occurring toxicosis is required. ABSTRACT P02 pharmacokinetic interactions of carprofen and omeprazole in dogs Ann Gaier 1; Susan Jones1; Hiroko Enomoto1; Mark Papich1; M. Katherine Tolbert2; Kristen Messenger1 1North Carolina State University; 2Texas A&M University Because omeprazole and nonsteroidal anti‐inflammatory drugs (NSAIDs) are often administered concurrently, the aim of this study was to determine the effects of omeprazole on the steady‐state pharmacokinetics of carprofen in dogs. We hypothesized that omeprazole would change the pharmacokinetics of carprofen in dogs affecting safety or efficacy. Carprofen (50 mg; approximately 4.4 mg/kg) was administered orally to 6 healthy adult Beagle dogs every 24 hours for 7 days alone, then with 10 mg (1 mg/kg) omeprazole administered orally twice daily in a two‐period sequential study with a 4‐week washout between treatments. Blood samples were obtained on day 7 of each treatment at pre‐determined time points for plasma (R‐) and (S+) carprofen enantiomer analysis by high performance liquid chromatography (HPLC). Pharmacokinetic parameters were calculated using noncompartmental methods. Paired t‐tests or Wilcoxon Rank Sum were used to compare parameters between groups (p < 0.05 significant). Coadministration of carprofen and omeprazole significantly altered the pharmacokinetics of carprofen for both the R(−) and S(+) enantiomers. Area‐under‐the‐curve (AUC) was lower, and terminal half‐life (T½) was shorter following concurrent carprofen and omeprazole administration than carprofen alone, while clearance (Cl/F) was significantly increased. Median S(+) AUC were 184.03 and 132.25 μg*hr/mL (p = 0.0118), Cl/F were 12.72 and 18.37 mL/hr/kg (p = 0.0246), and T½ were 8.8 and 6.7 hr (p = 0.0016) for carprofen only and carprofen plus omeprazole treatments respectively. R(−) AUC was 133.37 and 98.17 μg*hr/mL, Cl/F was 18.41 and 24.82 mL/hr/kg, and T1/2 was 7.13 and 6.0 hr, respectively. A pharmacokinetic interaction does occur between omeprazole and carprofen. The clinical significance of this interaction could involve decreased analgesia or anti‐inflammatory activity. ABSTRACT P03 Clinical efficacy of a long‐acting subcutaneous methadone solution for postoperative analgesia in dogs Butch KuKanich ; Kate KuKanich; Kara Berke; Emily Klocke; David Upchurch; Brad Crauer; Alyssa Comroe; Maria Jugan; Diane Mason; Gina Jensen; Zack Bieberly; Joshua Klutzke; Kallie Woodruff; Ally Fitzgerald; Ron Orchard; Kelsey Decker Kansas State University College of Veterinary Medicine Current injectable opioids for postoperative dogs require frequent injections to maintain analgesia. Fluconazole significantly increases the half‐life and duration of methadone. The purpose of this study was to compare the perioperative analgesia of subcutaneous methadone/fluconazole to subcutaneous standard methadone in dogs. We hypothesized subcutaneous methadone/fluconazole would provide 24 hours of analgesia with 2 doses. Forty‐one healthy female dogs were enrolled, blocked by body weight, and randomly allocated to one of two treatments. The positive control group (methadone STD) received subcutaneous 0.5 mg/kg methadone q4h. The experimental group (methadone/fluconazole) received subcutaneous 0.5 mg/kg methadone and 2.5 mg/kg fluconazole, repeated once at 6 hours. All dogs received perianesthetic acepromazine, propofol, and isoflurane. Experienced surgeons performed standardized ovariohysterectomies between 8 AM and 12 PM. Perioperative monitoring included the Glasgow Composite Pain Scale (GCPS) and sedation assessed as none, slight, moderate, profound or unresponsive. All dogs were administered oral carprofen starting 24 hours postoperatively per standard practice. There were no significant differences (p > 0.05) in postoperative GCPS scores between groups. One dog total (1/41) received rescue analgesia (methadone/fluconazole). Two methadone/fluconazole dogs had previous ovariohysterectomies (confirmed by abdominal exploratory). A single episode of vomiting occurred in 3 dogs (methadone STD) and 1 dog (methadone/fluconazole). All dogs were able to walk (moderate sedation or less) by 1 PM (methadone/fluconazole) and 4 PM (methadone STD) the day of surgery. Two doses of subcutaneous methadone/fluconazole provided 24 hours of perioperative analgesia. This should increase compliance and analgesic efficacy in veterinary clinics. ABSTRACT P04 Pharmacokinetics and safety of orally administered cannabidiol in domestic cats Aaron Rozental; Stephanie McGrath; Lisa Bartner; Breonna Thomas; Daniel Gustafson Colorado State University As cannabidiol (CBD) continues to gain popularity, understanding the science behind its use in domestic animals is essential. The objective of this study was to determine the single‐dose pharmacokinetic properties of orally administered highly purified CBD in healthy research cats. Eight cats were included in the study. For each dosing round, the cats were randomly divided into groups of four and assigned to receive a single dose of CBD oil at a low‐dose (2.5 or 5 mg/kg); a mid‐dose (10 or 20 mg/kg); and a high‐dose (40 or 80 mg/kg). Blood was collected at 0, 2, 4, 6, 12, and 24 hours for plasma CBD analysis. Between each dose, the cats underwent a two‐week washout period. The mean half‐life, time to maximal concentration, and mean retention time across all doses was 6.2, 4.1, and 9.6 hours respectively. The median maximal concentration for each dose (2.5, 5, 10, 20, and 40 mg/kg) was 16.1, 28.1, 73.5, 133.8, 87.0, 556.5 ng/mL respectively. The mean area under the curve for each dose was 134.5, 402.3, 483.4, 1,281.0, 724.1, 5,875.4 ng‐h/mL respectively. There were no severe adverse effects noted in any of the cats. Several cats exhibited head shaking and excessive salivation at the time of CBD administration. Mild lethargy was noted in all cats at doses of 40 and 80 mg/kg. No clinically significant alterations in bloodwork (CBC and chemistry profile) were noted in any cat. A single oral dose of CBD up to 80 mg/kg was safe in this cohort of cats. ABSTRACT P05 predicting uropathogen identity and susceptibility using patient signalment and urine biochemical tests William J. Love; Shelly Vaden; Mark Papich; Megan Jacob; Cristina Lanzas College of Veterinary Medicine, North Carolina State University Urinary tract infections (UTIs) are one of the most common indications for antimicrobial administration in dogs and cats. Despite the recent emphasis on antimicrobial stewardship, there has been little progress to improve the information available to clinicians for antimicrobial selection. Cumulative antibiogram tables are one of the few tools available, but the currently published tables are only divided by sample source if at all. More individualized antibiograms could provide more relevant susceptibility data and better stewardship. The objective of this study is to identify patient signalment and biochemical urinalysis (UA) data that can improve pathogen and susceptibility prediction. A retrospective study was performed using aerobic urine cultures and AST results (n = 999) collected from dogs treated at the NC State Veterinary Hospital in Raleigh, NC between 2014 and 2018. Analysis was limited to the six most common pathogens: Escherichia coli (n = 451), Staphylococcus pseudintermedius (n = 101), Enterococcus faecalis (n = 93), Enteroc. faecium (n = 41), Proteus mirabilis (n = 85) and Klebsiella pneumoniae (n = 44). Susceptibility results were available for 11 antimicrobials: ampicillin, amoxicillin + clavulanic acid, cefazolin, cefovecin, cefpodoxime, chloramphenicol, doxycycline, enrofloxacin, marbofloxacin, gentamicin, and trimethoprim + sulfamethoxazole. Signalment data included patient sex, age, and body weight and UA data included urine protein, glucose, ketones, specific gravity, pH, and bacteriuria. The probability of isolate susceptibility given patient profile was estimated logistic regression models and a multinomial regression model was used to estimate probability of pathogen presence. Predictive performance was cross‐validated using a 100 isolate subset. The logistic regression models identified several factors significantly associated with susceptibility probability for several antimicrobials. Fluroquinolone susceptibility was increased in alkaluric samples (enrofloxacin OR = 1.6, p = 0.03; marbofloxacin OR = 1.7, p = 0.01) and bacteriuric samples (OR = 1.8, p < 0.01 for both). Isolates from male dogs were more likely to be susceptible to marbofloxacin (OR = 1.6, p = 0.03) and gentamicin (OR = 1.8, p = 0.01). Doxycycline susceptibility was decreased in isolates from alkaluric samples (OR = 0.5, p < 0.01). Body weight and age were not found to significantly affect susceptibility. The multinomial regression found at least one signalment or UA covariate significantly associated with the probably of an organism compared to E. coli as the referent organism. The gram‐positive species were less common in samples with significant bacteriuria (E. faecalis OR = 0.47, E. faecium OR = 0.25, S. pseudintermedius OR = 0.34, p < 0.01 for all results). Male dogs were more likely to culture K. pneumoniae (OR = 2.8, p = 0.01) and less likely to culture P. mirabilis (OR = 0.35, p < 0.01). Samples from alkaluric dogs were more likely to culture S. mirabilis (OR = 6.1, p < 0.01) or S. pseudintermedius (OR = 3.1, p < 0.01). Despite the significant results in the training models, neither the multinomial model (ΔG = 6.8, p = 0.81) nor the neither the logistic models (best fit enrofloxacin ΔG = 10.3, p = 0.57). This could possibly be improved with a larger sample size or alternative fitting approaches, e.g., machine learning techniques. Also, identification of uncomplicated versus complicated UTIs and underlying specific urogenital pathology, e.g., urolithiasis, anatomic abnormalities, and metabolic disorders, may also provide more valuable predictive information and will be explored in future studies. The current study demonstrates that patient profile and UA data may influence bacterial uropathogen identity and susceptibility but does not significantly improve prediction using these methods. These results indicate which patient data could be used to improve interactive dynamic cumulative antibiogram tables, either by weighting or stratifying historic susceptibility data, to be more relevant to individual patients. ABSTRACT P06 Efficacy of long‐acting methadone using a combination of oral and injectable formulations in perioperative dogs Butch KuKanich ; Kate KuKanich; Emily Klocke; Yoshihiro Azuma; Nora Springer; Gina Jensen; Micaela Freeman; Alyson Fitzgerald College of Veterinary Medicine, Kansas State University The purpose of the study was to evaluate the perioperative efficacy and tolerability of subcutaneous methadone/fluconazole followed by oral methadone/fluconazole/naltrexone (methadone) compared to intramuscular buprenorphine followed by oral codeine (buprenorphine). Enrollment included intact dogs (n = 239 total; n = 119 for methadone, n = 120 for buprenorphine) for ovariohysterectomy or castration as part of a surgery class (IACUC approved). Dogs were later placed for adoption. One dog (methadone) was excluded from postoperative assessment due to an additional surgery to control hemorrhage. Methadone/fluconazole (0.5/2.5 mg/kg) was administered SC preoperatively and once postoperatively; oral methadone/fluconazole/naltrexone (0.5/2.5/0.125 mg/kg) q12h started ~24 h postoperatively. Buprenorphine was administered preoperatively (0.02 mg/kg IM) and postoperatively (0.01 mg/kg IM); oral codeine administration (1–2 mg/kg q8h) started ~8 h postoperatively. All dogs received NSAIDs daily starting ~24 h (methadone) or ~ 8 h (buprenorphine) postoperatively. All dogs received acepromazine (premedication), ketamine/midazolam (induction) and isoflurane anesthesia. Third year veterinary students performed anesthesia and surgery with faculty oversight. The Glasgow Composite Pain Scale‐Short Form assessed postoperative pain; treatment failures included total pain scores exceeding 6 or need for additional postoperative analgesia/sedation. Enrollment included 47 castration, 72 ovariohysterectomy (methadone) and 44 castration, 76 ovariohysterectomy (buprenorphine) procedures. Propofol was additionally needed for anesthesia induction in 2/119 methadone and 8/120 buprenorphine dogs. Ephedrine was administered for intraoperative hypotension in 4/119 (methadone) and 8/120 (buprenorphine) dogs. One dog (methadone) received intraoperative atropine. Mean ± SD postoperative rectal temperatures were 96.1 ± 2.0 °F (methadone) and 97.0 ± 1.7 °F (buprenorphine). Treatment failures included 1/118 (methadone) and 8/120 (buprenorphine) dogs. Methadone/fluconazole ± naltrexone was effective and well tolerated in perioperative dogs. ABSTRACT P07 Clinical assessment of transdermal gabapentin in cats Jennifer E. Slovak 1; Nicolas Villarino2 1Animal Medical Center‐NYC; 2Washington State University The clinical use of gabapentin in veterinary medicine has recently surged and has provided clinicians an alternative to opioids and non‐steroidal pharmaceuticals for painful patients, especially cats. However, when used chronically, the frequency, dose, and manner of administration can be challenging for some owners. Transdermal drug administration is often desirable for medicating cats and can help eliminate negative human‐animal bond interactions, increase owner compliance, and minimize stress in a diseased patient population. There is evidence of transdermal in vitro gabapentin penetration in cats, but it is unclear what occurs in vivo. The use of transdermal delivery mechanisms is challenging because of species differences in skin structure, barrier properties of skin, ratio of the skin area required for optimal drug absorption and lipid solubility of the medications used. The purpose of our research was to investigate whether transdermal gabapentin used in a proprietary base, (Lipoderm®) at pre‐determined concentrations would permeate feline skin in vivo in a healthy patient population. A second objective of this study was to determine if painful cats responded to transdermal gabapentin administration based on validated pain scores before, during, and after treatment. The initial pilot study (IACUC ASAF # 6379) consisted of 8 client‐owned young (< 6 years) healthy cats assigned to one of the following groups: 5 mg/kg TID or 10 mg/kg TID of transdermal gabapentin applied to either the cervical region or ear pinna, with 4 groups in total. Two cats were randomly assigned to each group. Gabapentin was pre‐formulated to 250 mg/ml (not exceeding 0.2 mls) volume of medication per dose in Lipoderm®. All cats had serum samples obtained pre‐dose and at 1, and 5 days after starting the transdermal medication. Serum samples were immediately frozen at −80°C and sent for batch drug concentration analysis utilizing a validated HPLC mass‐spectrometry method. Results showed detectable levels of gabapentin for all cats in all groups at day 1 (0.18–1.3 μg/mL) and day 5 (0.11–5.4 μl/mL). There was no difference when comparing gabapentin concentration (5 vs 10 mg/kg) and skin location (cervical versus ear pinna) for this group of cats (p > 0.05). Descriptive statistics and an overall F‐test were used to analyze the data. The clinical study (IACUC ASAF # F‐8‐19‐19‐G) consisted of 15 client‐owned cats over 8 years of age. All cats were examined to be clinically stable and, on no medications despite underlying conditions (up to IRIS stage 2 kidney disease, osteoarthritis, and/or obesity). All cats were administered 10 mg/kg of transdermal gabapentin in a Lipoderm® base TID. Recorded pain scores using 2 validated feline pain assessment scales were recorded pre‐dose and on days 1, 5 and 8 (gabapentin was discontinued after day 5). Quantification of serum gabapentin levels were performed pre‐dose and day 1 and 5 of the study. Serum samples were immediately frozen at ‐80°C and sent to the same laboratory used in the pilot study for batch drug concentration analysis utilizing a validated HPLC mass‐spectrometry method. Descriptive statistics and a repeated measures ANOVA were utilized for data analysis. Results showed detectable levels of gabapentin at day 1 (0.1–1.47 μg/mL) and day 5 (0.31–3.38 μg/mL) in all cats. The mean gabapentin level at day 1 was 0.6 μg /mL SD ± 0.51 and 1.32 μg/mL SD ± 0.99 at day 5. There was a significant difference in gabapentin levels from day 1 to day 5 (p < 0.02). There was no significant statistical difference in pain scores between pre‐ dose and day 8 in any of the cats for either pain scale. There was a significant difference in pain scores of the cats for both pain scales when comparing pre‐dose to day 5 (p < 0.05) and when comparing day 1 to day 5 (p < 0.05). The results of this study confirm that gabapentin can be absorbed trans‐dermally in cats and that gabapentin levels increase from day 1 to day 5 after trans‐dermal administration. Pain scores also improve from pre‐dose to day 5 and day 1 to day 5 after transdermal application of gabapentin. By day 8 (3 days post discontinuation of transdermal gabapentin), pain scores returned to pre‐dose values. Future studies evaluating the chronic use of gabapentin (>1 month) in cats and its use in cats with various stages of kidney disease should be evaluated. ABSTRACT P08 Pharmacokinetics, sedative, and physiological effects of trazadone in cats alone or in combination with gabapentin Laura Tucker; Andrea Sanchez; Shauna Blois; Ron Johnson; Alexander Valverde Ontario Veterinary College The objective of this study was to determine pharmacokinetics, physiological, and sedative properties of trazadone alone or in combination with gabapentin in healthy cats. Six systemically healthy research cats were given trazodone (3 mg/kg) IV, trazodone (5 mg/kg) PO, or a combination of trazodone (5 mg/kg) and gabapentin (10 mg/kg) PO in a randomized, crossover design with a one‐week washout period. Heart rate, respiratory rate, indirect blood pressure, and level of sedation were assessed for 24 hours. Venous blood samples were collected at 3, 5, 10, 20, 30, 45, 60 minutes and 2, 4, 6, 8, 10, 12, and 24 hours post‐administration in the IV group, and at the same time points starting at 10 minutes in the PO groups. Analysis of plasma trazodone concentration was performed using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Oral trazodone administration resulted in rapid absorption (Tmax = 10 min). Addition of gabapentin resulted in lower bioavailability (29.7% vs 59.2%), shorter half‐life (4 vs 5.2 hr), larger volume of distribution (7159 vs 4658 ml), and faster clearance (1234.7 vs 619.8 ml/hr) compared to trazodone alone. Sedation was significant in all groups from 1 to 8 hr post‐trazodone; addition of gabapentin resulted in a similar degree of sedation. Physiological parameters were not significantly impacted by any treatment. This study concludes that oral trazodone at the dose tested is a safe and effective option for sedation in cats with some lag between peak plasma concentration and sedation effects. Combination with gabapentin did not result in significant clinical advantages. ABSTRACT P09 the influence of butorphanol on the sedative and cardioventilatory effects when co‐administered intramuscularly with medetomidine‐vatinoxan Heta Turunen Vetcare Oy Butorphanol can be used in combination with α2‐adrenoceptor agonists, such as medetomidine or its pharmacologically active enantiomer dexmedetomidine, to enhance sedation and muscle relaxation in dogs.1 Vatinoxan (also known as MK‐467 and L659'066) is a peripheral α2‐adrenoceptor antagonist that reduces the adverse cardiovascular effects of α2‐adrenoceptor agonists without substantially altering the level of sedation.2,3 We aimed to study the influence of butorphanol on the intensity and duration of sedation as well as cardioventilatory effects in dogs treated with a medetomidine‐vatinoxan combination drug. We hypothesized that the dose of the medetomidine‐vatinoxan combination drug could be reduced with the addition of butorphanol to achieve a similar or improved sedative effect compared to that produced by a full dose of the medetomidine‐vatinoxan combination drug, and that butorphanol would not cause detrimental cardioventilatory effects. This was a prospective, randomized, blinded, experimental cross‐over study where eight healthy instrumented Beagle dogs were given intramuscularly a combination of medetomidine (1 mg/m2) and vatinoxan (20 mg/m2) or a combination of medetomidine (0.6 mg/m2) and vatinoxan (12 mg/m2) with butorphanol (0.1 mg/kg) mixed in the same syringe. Sedation scores were determined with a validated sedation scale4 by a blinded investigator at 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90 and 120 minutes after drug administration. Cardioventilatory safety of the treatments was evaluated by continuous heart rate, electrocardiogram, arterial blood pressure and respiratory rate recordings. Differences between treatments were evaluated with a linear mixed model and Dunnett adjustment for multiple comparison (p < 0.05). Sedation scores were significantly higher with treatment including butorphanol at 10 minutes and from 35 to 120 minutes after intramuscular drug administration. Coadministration of butorphanol with the medetomidine‐vatinoxan combination drug provided faster onset of deeper sedation and also increased the duration of sedation with the doses used in the present study. No adverse effects or significant differences in heart rate, arterial blood pressure and respiratory rate between treatments were detected. To conclude, butorphanol can be used without disadvantageous cardiovascular or ventilatory effects to increase the depth and length of sedation induced by a medetomidine‐vatinoxan combination drug when administered at a 40% reduced dose. REFERENCES 1. Kuo W, Keegan R. Comparative cardiovascular, analgesic, and sedative effects of medetomidine, medetomidine‐hydromorphone, and medetomidine‐butorphanol in dogs. Am J Vet Res. 2004;65:931‐937. 2. Honkavaara J, Raekallio M, Kuusela E, et al. The effects of L‐659,066, a peripheral α2‐adrenoceptor antagonist, on dexmedetomidine‐induced sedation and bradycardia in dogs. Vet Anaesth Analgesia. 2008;35:409‐413. 3. Rolfe N, Kerr C, Mcdonell W. Cardiopulmonary and sedative effects of the peripheral α2‐adrenoceptor antagonist MK 0467 administered intravenously or intramuscularly concurrently with medetomidine in dogs. Am J Vet Res. 2012;73:587‐594. 4. Wagner M, Hecker K, Pang D. Sedation levels in dogs: a validation study. BMC Vet Res. 2017;13:1‐8. 5. Bennett R, Salla K, Raekallio M, et al. Effects of MK‐467 on the antinociceptive and sedative actions and pharmacokinetics of medetomidine in dogs. J Vet Pharmacol Ther. 2016;39:336‐343. 6. Honkavaara J, Restitutti F, Raekallio M, et al. Influence of MK‐467, a peripherally acting α2‐adrenoceptor antagonist on the disposition of intravenous dexmedetomidine in dogs. Drug Metab Dispos. 2012;40:445‐449. ABSTRACT P10 Pharmacokinetics of cannabinoids from industrial hemp oil in felines Rebekah C. Strunk; Carolyn Warner; Robert Gillette; David Griffin Travco Products, Inc In recent years, interest in use of cannabinoids for medicinal purposes in humans has risen causing an increase in curiosity in the veterinary world. Currently, research is limited showing the clinical benefits of cannabidiol or other phytocannabinoids in dogs or cats. There are, however, multiple studies published showing bioavailability of cannabidiol in humans and dogs, but only one in cats currently exists. The findings of that study showed low bioavailability with oil in capsules for cats. The present study evaluated the pharmacokinetics (PK) of full spectrum hemp as an oil or gel formulation (containing NMXCB1220™) given orally in a research population of cats. Eight cats (n = 8) were randomized to two treatment groups (oil or gel) and crossed‐over after a 7‐day washout. The plasma samples were collected at the following time points pre‐treatment, 1, 2, 4, 8, and 24 hours. Calculated Cmax, Tmax, and area under the curve (AUC) parameters for plasma CBD concentrations were subject to logarithmic transformation to adjust for normality and analyzed using one‐way ANOVA to compare treatment effects. Significant differences were noted between treatment groups for Cmax (p < 0.001) and AUC (p < 0.001), with the gel showing six times higher mean peak concentrations (Cmax) compared to the oil (relative bioavailability (F) =1.57). Tmax was not significantly different between the two groups. This study shows that cannabidiol from hemp given orally to cats is greatly influenced by delivery method. The gel hemp formulation in the present study displayed greater bioavailability than the oil. Data suggests that an oil may not be the most efficient delivery of hemp phytocannabinoids in felines. Further research is needed to determine the specific effects cannabidiol may have in cats. ABSTRACT P11 Evaluation of proton pump inhibitor use in canine patients hospitalized in a tertiary referral hospital Samantha Duxbury 1; Emily Sorah1; Patti Andrews1; M. Katherine Tolbert2 1College of Veterinary Medicine, North Carolina State University; 2Texas A&M College of Veterinary Medicine Although proton pump inhibitors (PPIs) are commonly administered to hospitalized dogs, prescribing patterns and appropriateness of use has been inadequately characterized. The objective of this study is to describe the prescription patterns and appropriateness of use associated with PPIs in hospitalized dogs at a tertiary care facility. We hypothesized that the majority of prescriptions would not comply with current guidelines for the rational use of acid suppressants. A retrospective evaluation was performed of the medical records associated with a randomly selected population of hospitalized dogs receiving PPIs January 2013–December 2018. A total of 12,610 canine patients were admitted for a first‐time hospitalization January 2013–December 2018. 40% of these patients (5062/12610) were prescribed an oral or intravenous PPI. An adequate indication for use was identified in 27% of patients (54/200). Of the patients surviving to discharge 54% (95/175) were discharged with a PPI and 61% (58/95) of those patients were prescribed an inappropriate dose. The majority of PPI prescriptions to hospitalized dogs at a tertiary care hospital lacked an appropriate indication. With the growing concern of adverse effects secondary to PPIs in human medicine, rationale use of these medications should be emphasized and reserved for patients with physical exam and clinicopathologic findings supportive of an adequate indication for use. Furthermore, analysis of the prescribing patterns of dispensed PPIs revealed a frequent occurrence of dosages considered inadequate for treatment of upper GI ulceration and bleeding, raising concern for ineffective therapy even with appropriate indications of use. ABSTRACT P12 The pharmacokinetics of long‐term, low‐dose oral rapamycin in healthy, middle‐aged, medium‐to‐large breed dogs Jeremy B. Evans 1; Ashley Morrison1; Martin Javors2; Marisa Lopez‐Cruzan2; Matt Kaeberlein3; Daniel Promislow3; Kate Creevy3 1Texas A&M Veterinary Teaching Hospital; 2UT Health San Antonio; 3University of Washington; 4Texas A&M University Rapamycin is a macrolide antibiotic that targets mTORC1, an extensive regulatory metabolic pathway. While rapamycin is used as an immunosuppressant, numerous other potential uses are being investigated. Rapamycin has been studied extensively in humans and rodents, but few studies in canines exist and only utilize short courses of therapy. This study aimed to determine the pharmacokinetics of long‐term (range 1–6 months; mean = 3.5 ± 1.8), low‐dose (0.25 mg/kg) oral rapamycin in dogs. Seven healthy, middle‐aged to senior dogs (three spayed females, four castrated males) between the ages of 6–10 (mean = 9.4 ± 1.1) years‐old and weighing between 40–80 lbs were enrolled. All dogs had previously been recruited into a 12‐month prospective, double‐blinded, placebo‐controlled study where they would receive rapamycin or a placebo 3 times a week (Monday, Wednesday, and Friday) for 6 months. Participating dogs underwent a fasted blood draw at timepoint 0, were given breakfast and their treatment, and underwent additional blood collection at 1, 2, 6, and 24 hours afterwards. Prior to treatment, no dog had detectable levels of rapamycin. In the 4 dogs that received rapamycin, drug concentration peaked 2 hours after ingestion, with the mean serum concentrations being 0.99 ± 0.1 ng/ml at 1 hour, 1.49 ± 0.6 at 2 hours, 0.96 ± 0.7 at 6 hours, and 0.5 ± 0.6 at 24 hours. Dog #4, the only dog who ate breakfast, had consistently but not significantly higher rapamycin concentrations at all time points, suggesting a possible influence of prior food consumption on rapamycin absorption. The results of this study indicate that the employed low‐dose regimen of rapamycin results in low but clinically measurable serum concentrations of rapamycin which do not persist for 48 hours.   ABSTRACT P13 Variability in plasma cannabidiol concentrations in dogs receiving CBD‐containing products Jeremy A. George 1; Benjamin Driggers2; Crisanta Cruz‐Espindola2 ; Christina Hargis2; Harmon Roy2; Dawn Boothe2 1Auburn University; 2College of Veterinary Medicine, Auburn University Cannabidiol (CBD), one of two major phytocannabinoids in marijuana, is associated with evidence of therapeutic benefit as is demonstrated by its approval for treatment of drug refractory epilepsy in children. However, pet owners have been administering CBD‐containing products for several years despite lack of scientific evidence. Legalization of industrial hemp is likely to increase this use. The purpose of this study was to demonstrate variability of plasma CBD in canine patients receiving CBD‐containing products. Using UPLC‐MS (assay validated for canine plasma), CBD and THC were quantitated in canine blood samples (n = 338) received by Auburn University Clinical Pharmacology Lab's Therapeutic Drug Monitoring (TDM) program from February 2016 through October 2019. Samples were submitted specifically for CBD analysis (n = 183) or were analyzed because the submission form for an alternate drug indicated the patient was also receiving CBD (n = 55). Data accompanying submission forms included patient signalment, diagnosis, concomitant drugs, the name and formulation of the CBD product, and dosing regimen. Not all information was provided for all samples. Of the 206 submission for which products manufacturer were identified, 44 different products were being used. The most common formulation was hemp oil (n = 254) followed by capsule (n = 38) and biscuit/treat/chewable/tincture (n = 20) (31 unreported). The labeled active ingredient concentration ranged from 1 to 100 mg/mL for oils and 15 to 525 mg/capsule. The dosing regimens varied from 1 to 710 mg (median 14.97 mg, interquartile range (IQR) of 6–30.15 mg, n = 182) or 0.056 to 35.5 mg/kg (median 0.7 mg/kg, IQR = 0.28–1.56 mg/kg, n = 178). CBD (ng/mL) ranged from nondetectable (ND) to >1000 ng/mL (median 13.7 ng/mL, IQR = 2.01–55.95 ng/mL, n = 187). THC ranged from ND to 87.43 ng/mL (median 0.6 ng/mL, IQR = 0.01–1.85 ng/mL). When adjusted for dose, CBD concentrations in patient receiving oils ranged from 0.072 to 976 ng/mL (median 35.38 ng/mL, IQR 5.34–106.51 ng/mL, n = 64) compared to non‐oils of 0.052 to 425.74 ng/mL (median 10.92 ng/mL, IQR 1.68–200.48 ng/mL, n = 15). This data demonstrates the marked variability in CBD concentrations achieved in patients receiving supplements, reflecting in part, variability in products, formulations, and dose. The need to provide standard recommendations is evident, particularly when implementing clinical trials, and monitoring may be a useful tool for standardizing product uses. ABSTRACT P14 Pharmacokinetics and diuretic effect of intravenous, tablet, developed oral disintegrating film of furosemide in dogs Dong‐hyuk Kwak 1; Suk‐kyu Koh1; Jong‐woo Jeong2; Gwan‐hyung Jo3; Tae‐sung Koo2; Kyoung‐won Seo1 1College of Veterinary Medicine, Chungnam National University; 2Graduate School of New Drug Discovery and Development, Chungnam National University; 3College of Pharmacy, Inje University Furosemide, a diuretic acting on the Henle's loop, is commonly used to treat congestive heart failure in veterinary medicine. Some owners have difficulty administering oral tablet medications to animals ‐ who are noncompliant and long‐term administrations can also make it very challenging. Oral disintegrating film (ODF) is a non‐invasive application with rapid dissolution, which prevents the risk of swallowing. Objectives of this study were to research pharmacokinetic and pharmacodynamics profiles by comparing each routes; intravenous (IV), orally uncoated tablet (OUT) and newly developed ODF, following administration of furosemide in healthy beagle dogs. Five beagle dogs were administered a single dose (2 mg/kg) of furosemide loaded ODF, developed by the research team, using a cross‐over design. The most suitable film forming agent was sodium alginate which was used to manufacture ODF. In aspect to size of the films, it was developed for ease of use in small animals. There were no significant differences in the pharmacokinetic profiles between OUT and ODF. Cmax was higher but T1/2 and Tmax were slightly shorter with ODF, when compared to OUT method. ODF resulted in a similar hourly urinary output, when compared with OUT, during the initial 2 hours after administration. These finding suggest that the pharmacokinetics and pharmacodynamics after administration of newly developed ODF are equivalent to that of OUT. Therefore, ODF formulations of furosemide have the benefit of easy and convenient administration, which would be helpful to patients and owners in veterinary medicine. Table 1. Pharmacokinetic parameters of furosemide (2 mg/kg) by route of administration in beagle dogs p Pharmacokinetic parameters IV OUT FS‐ODF OUT vs. FS‐ODF Cmax(μg/mL) 6.30 ± 0.78 (6.46) 0.61 ± 0.31 (0.69) 0.81 ± 0.81 (0.58) 0.619 Tmax(h) 0.083 (0.083) 1.05 ± 0.45 (1) 0.65 ± 0.29 (0.75) 0.130 T1/2(h) 2.07 ± 0.76 (1.63) 3.46 ± 1.82 (2.86) 2.65 ± 0.77 (2.46) 0.602 MRT (h) 0.90 ± 0.25 (0.782) 4.76 ± 1.59 (3.99) 3.36 ± 0.77 (3.45) 0.128 AUCinf(μg·h/mL) 2.74 ± 0.25 (2.60) 1.62 ± 0.77 (1.77) 1.28 ± 0.70 (1.36) 0.493 AUClast(μg·h/mL) 2.67 ± 0.260 (2.56) 1.27 ± 0.49 (1.53) 1.14 ± 0.64 (1.11) 0.734 F (%) 100 59.06 ± 27.95 (64.74) 46.91 ± 25.49 (50.01) 0.493 Cmax, maximum plasma concentration; Tmax, time at the maximum concentration; T1/2, elimination half‐life, MRT, mean residence time; AUCinf, area under the curve from time zero to time of infinity measurable concentration; AUClast, area under the curve from time zero to time of last measurable concentration; F,fraction of oral dose absorbed(=bioavailability), expressed as a percentage; IV, intravenous; OUT, orally uncoated tablet; FS‐ODF, furosemide‐loaded orally disintegrating film. Results are presented as mean ± SD (median). (*), values are significantly different (P < 0.05); (**) values are significantly different (P < 0.01).   17 ABSTRACT R01 Use of an in vitro larval motility assay evaluating anthelmintic efficacy against canine and feline metastrongyloids Daniela Bedenice 1; Haifaa Mahjoub2; Henrik Stryhn2; Spencer Greenwood2; Gary Conboy2 1Tufts Cummings School of Veterinary Medicine; 2Atlantic Veterinary College, University of Prince Edward Island Metastrongyloids are important causative agents of canine and feline respiratory and cardiopulmonary disease. The purpose of this study was to determine the in vitro efficacy of 6 common anthelmintics (fenbendazole, eprinomectin, ivermectin, milbemycin oxime, moxidectin, selamectin) on the motility (viability) of infective third‐stage larvae (L3) of Angiostrongylus vasorum, Crenosoma vulpis, and Aelurostrongylus abstrusus. First‐stage larvae (L1) of A. vasorum, C. vulpis and A. abstrusus were isolated from infected lung tissue or feces (red fox, dog or cat origin) using a lung flush or Baermann technique. Laboratory‐raised Limax maximus slugs were fed 1,500–3000 L1 and held at 16°C for 4 weeks to produce L3. Slugs were digested and 50–100 L3/well were incubated at 16°C for 3 days in culture media alone and media containing 4 different concentrations for each anthelmintic. Drug concentrations were chosen to bracket the expected in vivo drug plasma concentrations in anthelmintic‐treated dogs and cats (based on published pharmacokinetic studies). Motile and non‐motile L3 were manually counted using a dissecting microscope after each well was pulsed with warm digest solution to stimulate larval activity. L3 mortality was analyzed by multilevel logistic models, generating dose‐response relationships. Drug concentration estimates corresponding to a 50% larval mortality (M‐50) identified that C. vulpis was the most sensitive species to the anthelmintics tested. A. abstrusus was most susceptible to moxidectin (M‐50 = 117 ng/ml, 95%CI: 34–399) and selamectin (M‐50 = 1193 ng/ml, 95%CI: 694–2051), while A. vasorum was highly resistant to all anthelmintics tested, except for selamectin at high drug concentrations (M‐50 = 14 372 ng/ml, 95%CI: 6547–31 547). ABSTRACT R02 Whole genome sequence analysis of yorkshire terriers with tracheal collapse: Identification of an associated variant Dylan J. DeProspero 1 ; Eleanor Hawkins1; Steven Friedenberg2; Kathryn Meurs1 1NCSU College of Veterinary Medicine; 2UMN College of Veterinary Medicine Tracheal collapse, a progressive degenerative disease of the tracheal cartilage rings, results in dorsoventral flattening of the dorsal tracheal membrane and significant airway compromise. Increased prevalence in toy and small breed dogs, like the Yorkshire Terrier, suggests a genetic origin for this disease. We hypothesized that whole genome sequencing (WGS) could identify pathologic variant(s) that segregated with tracheal collapse. We aligned and compared WGS data from eight affected Yorkshire Terriers to the canine reference sequence and our WGS database of 174 control dogs (29 breeds) and 107 risk breed dogs (small breed dogs at increased risk of tracheal collapse). Variants in affected dogs were evaluated for pathogenic implications using the Standards and Guidelines for the Interpretation of Sequence Variants. Missense variants were evaluated using in‐silico programs (Polyphen, Sift, and Provean) for deleterious effects. Gene function was analyzed for impact on tracheal cartilage. Alcian Blue and Safranin O staining was performed on archival tracheal tissue from affected dogs to assess the cartilage for levels of glycosaminoglycans as well as proteoglycans and cell chondrogenesis, respectively. One variant, a deleterious polymorphism at Chr3:26,679,306 (Endofin, ZFYVE16), was found in seven out of eight affected Yorkshire Terriers but not in any control dogs; the variant was also identified in 22 dogs from at‐risk breeds. Additional Sanger sequencing of 41 affected Yorkshire Terriers and 59 unaffected risk‐breed dogs showed that the Endofin variant was significantly associated with tracheal collapse in affected Yorkshire Terriers (p = 0.007). Alcian Blue and Safranin O staining of tracheal tissue from affected dogs demonstrated a loss of chondroitin sulfate from the cartilage. Endofin functions to regulate membrane trafficking in the endosome and is involved in multiple signaling pathways, including the bone morphogenetic protein (BMP) pathway. Through the BMP pathway, Endofin regulates bone and cartilage formation and Endofin dysfunction could lead to decreased BMP signaling, resulting in the degenerative and dysfunctional cartilage seen in tracheal collapse dogs. Endofin's specific function in this pathway is to facilitate phosphorylation of the signal transducer complex SMAD1/5/8. The disruption of the BMP pathway by a non‐functional Endofin protein could explain the decrease in chondroitin sulfate commonly seen in affected tracheal collapse samples. Attempts to identify the difference in levels of Endofin and SMAD1/5/8 phosphorylation in the tissues using IHC was unsuccessful due to a uniform loss of cartilage, likely due to processing issues. Future work could entail repeating staining on additional fresher samples and with a wider spectrum of antibodies, which could be beneficial to discern if there truly was a difference between affected and unaffected samples. We identify here a variant in Endofin that is strongly associated with tracheal collapse and could result in the degenerative and dysfunctional cartilage seen in tracheal collapse dogs. This information furthers our understanding of the development of tracheal collapse in the Yorkshire Terrier and may lead to improved diagnosis and treatment for affected dogs. ABSTRACT R03 Detection of canine nasal disease using infrared thermography Tekla Lee‐Fowler ; Stuart Clark‐Price; Kara Lascola College of Veterinary Medicine, Auburn University Infrared thermography detects variations in heat signature and has been utilized in other species to non‐invasively identify respiratory disease. This pilot study aimed to determine if infrared thermography could be used to detect nasal disease in dogs. Dogs presenting for nasal disease were recruited for the study. Dorsal and rostral images were acquired using a Fluke TiX580 60 Hz thermal imaging camera. Images were analyzed using the accompanying software, and regions of interest were defined over the right and left nasal passages to determine the average temperatures. Temperature differences and imaging patterns were subjectively correlated with computed tomography (CT) and histopathology. Images acquired from 8 dogs (5 spayed females; 3 neutered males). Clinical sings included epistaxis (n = 6), bilateral mucopurulent discharge (n = 2), and sneezing (n = 1). Image analysis revealed a median temperature difference of 2.7°F on rostral images and 1.5°F on dorsal images between nasal passages, with the affected nasal passage having a higher temperature. The nasal passage with higher temperature correlated with obstructive lesions on CT (neoplasia = 6/8 dogs). Subjective analysis of images allowed correct identification of affected side in 7/8 dorsal and 6/8 rostral images. Minimal airflow obstruction (lymphoplasmacytic rhinitis = 1, focal inflammation/granuloma = 1) resulted in incorrect subjective assessment. Obstructive nasal disease results in a local temperature increase in the affected nasal passage that can be non‐invasively detected by infrared thermography. Further investigation is warranted to determine if thermography can assist in differentiation of nasal diseases and/or used for monitoring of disease progression and treatment. ABSTRACT R04 Documenting bacterial infection in canine aspiration pneumonia Jennifer Howard 1; Carol Reinero2; Gregory Almond1; Aida Vientós‐Plotts2 ; Leah Cohn2; Megan Grobman1 1College of Veterinary Medicine, Auburn University; 2College of Veterinary Medicine, University of Missouri The background is aspiration pneumonia (AP) may occur without secondary bacterial infection. Widespread antimicrobial use is in part driven by lack of study documenting prevalence of bacterial infection in AP (b‐AP). Our hypothesis and objectives are to determine canine b‐AP prevalence using bronchoalveolar lavage (BAL) cytology and culture, and identify risk factors and non‐invasive criteria for predicting b‐AP. We hypothesized <50% of dogs with AP would have b‐AP (positive cytology and culture), and non‐invasive markers would poorly predict b‐AP. There are 21 client‐owned dogs. This is a retrospective study at the University of Missouri and Auburn University (01/01/09–10/01/19). Inclusion criteria were radiographic diagnosis of AP and ≥1 risk factor, CBC, thoracic radiographs, and BAL cytology/culture collected within 48 hrs of presentation. Dogs receiving >1 dose of antimicrobials within 7 days of BAL were excluded. Thirteen predictors of b‐AP were assessed including predisposing conditions and radiographic score. Cohn's kappa coefficient determined agreement between cytology and culture. Mann‐Whitney‐Rank Sum test identified differences between groups (significance, p < 0.05). Only 21/426 dogs qualified for study enrollment; the most common reason for exclusion was lack of BAL collection (n = 378 dogs). Nine dogs had concordant BAL cytology and culture (both positive, n = 7; both negative n = 2) and 12 dogs had discordant results. No agreement was found between culture & cytology (κ:0.0). Bacterial‐AP was identified more frequently with megaesophagus (p = 0.03). No other markers were predictive of b‐AP (p > 0.05). The conclusion are bronchoscopy and BAL are underutilized in AP. Diagnosis of b‐AP is challenging with only one‐third of dogs having clear‐cut b‐AP. ABSTRACT R05 Six minute walk test in West Highland White Terriers with pulmonary fibrosis Elizabeth Rozanski 1; Luis Dos Santos1; Kay McGuire2 ; Lindsay Merkel3; John Rush1 1Tufts University; 2Westie Foundation of America; 3University of Minnesota West Highland White Terriers (WHWT) are recognized to have a fibrosing pulmonary disease. In people with pulmonary fibrosis (PF), the 6‐minute walk test (6MWT) is widely used to monitor progression of disease. The goal is this study was to evaluate the 6 MWT in healthy WHWT and in WHWT with PF. Healthy dogs were recruited at the National Specialty in Kimberton, PA in October 2019. Following owner consent, dogs were walked for 6 minutes outdoors and the distance recorded. The ambient temperature was 66 °F and overcast. WHWT with PF were recruited from the hospital population of affected dogs, and from a Facebook Support Group (Westie Lung Disease‐IPF in USA). Affected dogs were walked either outside or inside (e.g., during inclement weather). A diagnosis of PF was made based upon clinical examination and radiographs and/or CT scan. Distances between healthy dogs and affected dogs were compared. Additionally, as affected dogs are commonly older, the subgroup of healthy older WHWT (10 years and older) was separately compared to the affected dogs. Comparisons were made using a T‐test and commercially available software. A p value of <0.05 was considered significant. Thirty‐three healthy WHWT and 12 affected WHWT were enrolled. The mean distance walked by healthy dogs was 486 ± 27 m while the affected dogs walked 221 ± 83 m (p < 0.001). Older healthy WHWT (n = 8) walked 480 ± 32 m, which was also significantly (p < 0.001) farther than affected WHWT. There was no different between young and older healthy WHWTs. ABSTRACT R06 Laryngotracheobronchoscopy via laryngeal mask airway in cats and dogs: A 16‐year experience Yukihito Shiroshita 1; Teppei Suganuma1; Tomohiro Sakurai2; Kazuya Mamada1; Kenichi Inaba1; Sho Kusaba1 1 VeRMS Study Group; 2 VeRMS Tracheobronchoscopy in cats and small dogs is conventionally performed without intubation, with a complication rate of 30–40% and a mortality rate of 5.9%. Laryngotracheobronchoscopy via laryngeal mask airway (LTBS‐LMA) using a flexible bronchoscope provides a constant airway and oxygen supply during examinations from the larynx to the lungs in cats and small dogs and is easy to perform with the animals in supine position. However long‐term clinical studies are lacking. This study aimed to assess the practicality and safety of LTBS‐LMA in cats and small dogs. The endobronchial anatomy of dogs in supine position and bronchial distribution on chest X‐ray (CXR) were illustrated using four bronchoscopies, a 3D print, and a celluloid cast of the tracheobronchial tree of healthy dogs. Subsequently, the medical records of dogs and cats that underwent LTBS‐LMA between 2002 and 2019 were reviewed. Animals were categorized into three groups: cats (F), small dogs (S, <5 kg), and medium‐to‐large dogs (ML, >5 kg). Indications and LTBS‐LMA procedure outcomes were compared between groups using descriptive statistics and the chi‐squared test. Altogether, 820 LTBS‐LMAs in 572 cases (436 dogs, 136 cats) were included. The most common indications were abnormal CXR findings, chronic cough, and chronic dyspnea in F; and abnormal CXR findings, stridor, and chronic cough in the S and ML groups. LTBS‐LMAs were performed in 212, 325, and 283 times in the F, S, and ML groups, respectively, with 90% of the animals in supine position. In the F, S, and ML groups, brushing was performed in 153, 234, and 130; biopsy (laryngeal, n = 58; tracheal, n = 33; and bronchial, n = 39) in 55, 34, and 28; transbronchial lung biopsy in 23, 2, and 11; and bronchoalveolar lavage in 86, 139, and 127 LTBS‐LMAs, respectively. Endoscopic interventions included stenting in 51, argon plasma coagulation in 46, debulking in 21, balloon dilation in 9, foreign body removal in 6, and snare resection in 6 LTBS‐LMAs. The complication rates were 20.8%, 7.7%, and 4.6%; the mortality rates were 3.8%, 0.9%, and 1.1%, in the F, S, and ML groups, respectively. The mortality rate in cats decreased significantly (p < 0.01) from 25.0% (3/12) in the initial 2‐year period to 2.5% (5/200) in the 14‐year period after defining a candidate criterion of requiring a partial pressure of oxygen in arterial blood >60 mm Hg in room air. LTBS‐LMA provided endoscopic examinations and interventions from the larynx to the lungs in cats and small dogs with comparable practicality and safety to those in medium and large dogs. ABSTRACT R07 Quantitative proteomics of bronchoalveolar lavage in West Highland White Terriers with canine idiopathic pulmonary fibrosis Henna P. Laurila 1; Merita Määttä2; Rosemary Maher3; Rob Beynon3; Paul McNamara4 ; Minna Rajamäki5 1Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki; 2Faculty of Veterinary Medicine, University of Helsinki; 3Institute of Integrative Biology, University of Liverpool; 4Institute of Translational Medicine, University of Liverpool; 5Faculty of Veterinary Medicine, University of Helsinki, Finland Canine idiopathic pulmonary fibrosis (CIPF) is a fibrotic lung disease of West Highland white terriers (WHWTs) with poorly understood etiology. By measuring bile acids from bronchoalveolar lavage fluid (BALF), we showed that reflux microaspiration (MA) of gastrointestinal contents is associated with CIPF. Our aim was to identify BALF proteome differences between CIPF and healthy WHWTs by quantitative proteomics to find evidence of MA. BALF from 10 CIPF and 10 healthy WHWTs, as well as vomit and gastric juice from one dog, were digested by either trypsin or endopeptidase GluC. Resulting peptides were analyzed by shotgun proteomic analysis using liquid chromatography tandem‐mass spectrometry. Relative protein abundances for BALF from CIPF and healthy WHWTs were compared using principal component analysis (PCA) and ANOVA testing with adjustments for false discovery rate. BALF was additionally searched for pepsin and other gastric proteins. BALF total protein concentration was higher in CIPF than in healthy. Macrophage‐secreted proteins cathelicidin, protein S100 and transforming growth factor beta‐induced protein had a higher fold change in CIPF (11.06, 11.77 and 2.69, respectively) and carboxylic ester hydrolase had a lower fold in CIPF than in healthy (−3.67), q‐value <0.05. Only minor differences were detected in gastric protein abundance between CIPF and healthy with trypsin digestion and none with GluC. No pepsin peptides were identified. CIPF BALF proteome differs from healthy WHWTs in abundance of proteins related to immune defense and inflammation. Using proteome analysis, we showed no overt reflux aspiration in CIPF WHWTs when compared to healthy WHWTs. ABSTRACT R08 Impact of spacer design on drug delivery and potential drug cost implications Elizabeth Rozanski 1; Mark Nagel2; Shae Sartori2 1Tufts University; 2Trudell Medical International The use of valved holding chambers (VHCs), also referred to as ‘spacers’, enables inhaled medications to be delivered to animals. Inhaled steroids are effective therapeutics for the management of respiratory diseases and are an alternative to systemic steroids which may have short‐ and long‐term side effects. However, the delivery process is a critical component of aerosol drug delivery and must be considered when assessing drug performance. VHCs are designed to decelerate and capture the aerosol plume from a Metered Dose Inhaler (MDI) in order to alleviate coordination issues to give animals time to inhale the medication properly. Many animals have small tidal volumes that will require multiple breaths to empty the chamber of medication. Therefore, chamber design elements such as volume and length, the use of electrostatic‐dissipative materials, inhalation valve function, and the design of the mask interface can influence delivery performance, which impacts pulmonary deposition and desired therapeutic effect. The purpose of this in vitro study was to assess drug availability in a range of chambers in a clinically relevant setting to provide guidance to veterinarians when recommending a VHC. This study evaluated the impact of drug availability when using fluticasone (Flovent HFA 110 μg) MDI with a range of different VHCs available on the market: AeroKat* Chamber (Trudell Medical International), Vet one 2 in 1 Feline Chamber (MWI), and four devices found on Amazon.com; Canack Aerosol Chamber, AeroFlow FAC, PawGreet FAC, and Inhaler Spacer for Cat. Each chamber was evaluated by breathing simulator that was programmed to simulate the tidal breathing pattern of a cat (tidal volume 50 mL, Inspiratory/expiratory ratio = 1:2, 20 breaths per minute). Coordination delays between MDI actuation and inhalation by tidal breathing were imposed to simulate real‐world use conditions. Delays of 2, 5, and 10 seconds were investigated to determine the impact on delivered drug mass. The breathing simulator was coupled to a filter which in turn was attached to the mouthpiece of the device on test. The mass of drug collected on the filter is indicative of total drug availability to the animal. Following activation of the MDI and appropriate delay interval, the filter was subsequently assayed via high performance liquid chromatography and the mass of fluticasone propionate determined. VHC 2 s Delay 5 s Delay 10s Delay AeroKat* Chamber 22.4 ± 5.2 18.5 ± 0.5 17.7 ± 0.9 Vet one 2 in 1 Feline Chamber 12.8 ± 2.4 9.0 ± 1.6 7.3 ± 1.4 Canack Aerosol Chamber 9.9 ± 0.3 7.1 ± 0.4 5.3 ± 1.1 AeroFlow FAC 9.3 ± 0.4 7.7 ± 2.1 3.2 ± 0.5 PawGreet FAC 8.2 ± 0.6 6.0 ± 3.4 2.1 ± 0.8 Inhaler Spacer for Cat 0.2 ± 0.1 0.2 ± 0.1 0.2 ± 0.0 Availability of medication has implications for disease control and pet owner expense. Animals not well controlled may need higher doses of medication to control the animal's disease. For example, using the 2 s Delay results and AeroKat* Chamber as a reference, owners delivering a Flovent* 110 inhaler (2 puffs per day, 60/month, $280 per MDI) could experience increased drug costs of between $1,246–$3,774 annually. With new products entering the veterinary sphere and increasing access to online selling marketplaces, these devices need to be evaluated in order to validate drug delivery performance. Without this information, devices that appear similar but perform differently could mean that some patients will not receive the intended dose and as a result be at heightened risk of poor disease control and potential for respiratory exacerbation. ABSTRACT E02 Heart rate variability during exercise and recovery in thoroughbred racehorses presented for poor performance Anna N. Hammond 1; Melanie Hezzell1; Sarah Smith1; Samantha Franklin2; Kate Allen1 1University of Bristol; 2University of Adelaide Heart rate variability (HRV) measures the beat‐to‐beat variation of successive cardiac cycles. There are few studies investigating HRV at exercise, although assessment of HRV may facilitate identification of arrhythmias. This study explored relationships between HRV during exercise and recovery, and pathologies (arrhythmias, lameness, gastric ulceration, airway inflammation and upper respiratory tract obstructions) in poorly performing Thoroughbred (TB) racehorses. One hundred and eighty‐three TBs underwent a high‐speed treadmill exercise test with an exercising electrocardiogram (ECG) recorded. ECGs were analyzed using Televet 100™, divided into peak exercise and recovery portions and examined for rhythm abnormalities. HRV data were derived using specialized software (Kubios™). The derived HRV variables included the standard deviation of normal to normal intervals (SDNN), the root mean square of successive differences (RMSSD), the R‐R triangular index (RRTI), the triangular interpolation of R‐R intervals (TINN) and the stress index (SI) which is a square root derivation from the histogram of R‐R intervals. Horses were categorized according to arrhythmia during exercise (yes/no), arrhythmia during recovery (yes/no), lameness (yes/no), upper respiratory tract obstruction (yes/no) and airway inflammation (yes/no). Proportions were compared using the Chi squared test. Correlations were assessed using Spearman's Rho. Univariate and multivariable general linear models were constructed to assess associations between each HRV measure during recovery, the same HRV measure during exercise, and clinical variables. Variables were logarithmically transformed if the residuals were not normally distributed. If no suitable transformation was possible, differences in HRV variables between clinical categories were assessed using Mann‐Whitney U tests. p values <0.05 were considered significant. More horses had arrhythmias during recovery than exercise (104/183 vs. 60/183, p < 0.001) and the proportion of complex arrhythmias was higher during recovery (39/104 vs. 3/60, p < 0.001). Arrhythmia during exercise (AEx) was not correlated with the presence of arrhythmia during recovery (ARec, p = 0.446). During exercise, none of the HRV variables were associated with any of the clinical variables (p > 0.05 in all cases) except RRTI with AEx (p = 0.023). During recovery, AEx and ARec were the only independent predictors of any HRV measure: Log SDNN (p = 0.030 exercise, p = 0.027 recovery), log RRTI (p = 0.028 exercise, p = 0.025 recovery), log TINN (p = 0.038 exercise, p = 0.005 recovery) and SI (p = 0.031 exercise, p = 0.001 recovery). During recovery, RMSSD was significantly different between categories for AEx (p = 0.010) and ARec (p = 0.039); no other differences between clinical categories were detected. In conclusion, AEx, gastric ulceration, respiratory disorders and lameness have little impact on HRV during exercise in poorly performing TB racehorses. However, during recovery HRV is influenced by AEx and ARec, but not by gastric ulceration, respiratory disorders or lameness. ABSTRACT E03 Repeatability and reproducibility of collapsibility index of jugular veins in healthy adult horses: Pilot study Ludovic A. Tanquerel; Aude Giraudet Clinique Equine, Ecole Nationale Vétérinaire d'Alfort Collapsibility Index (CI) is a noninvasive ultrasound method used in human medicine to estimate volemia, and has not been described in adult horses. The objectives were to investigate the repeatability, and reproducibility of CI of Jugular Veins (JV) in healthy adult horses. Ultrasound was performed on 26 JV of 13 healthy adult horses (9 WB, 2 SB, 2 others). Mean weight was 540 kg (SD = 45), and mean age was 11 yo (SD = 5). Ultrasound of both JV was performed with a 5 MHz linear probe by positioning the probe on the brachiocephalicus muscle (to avoid compression of the vein), with the head of the horse in neutral position. Anatomic M‐mode were performed and CI was calculated as: CI (%) = ([maximum JV diameter] ‐ [minimum JV diameter])/[maximum JV diameter]. Ultrasounds were performed by 2 operators, and measures were repeated twice. Bland‐Altman plots were produced. Acceptable agreement was considered to be present if bias were less than 20% and if the Limits Of Agreement (LOA) were included in [−20%; +20%]. For repeatability, bias were acceptable in 6/6 plots, and LOA were not acceptable in 6/6. For reproducibility, bias were acceptable in 6/6 plots, and LOA were not acceptable in 6/6. Based on this preliminary results, CI of the external jugular vein in adult horses has a poor repeatability and reproducibility. Further studies with more horses are needed before using CI as a clinical tool in horses.   ABSTRACT E04 Factors affecting cardiac auscultation in the horse Gayle D. Hallowell; Paul Lewis; James Heale; James Bailey; Adam Redpath; Steffi Pratt; I Mark Bowen School of Veterinary Medicine and Science, University of Nottingham The main objective of this study was to evaluate factors affecting the heart sounds that could be auscultated in the adult. 248 horses were auscultated by at least 5 individuals. Records were made regarding operator experience, body condition score, hair length, ambient noise level, breed type, heart rate, which heart sounds could be auscultated in the 4th and 5th left and right intercostal spaces. Any murmurs and dysrhythmias were also recorded. The standard stethoscope used by the individual was used for the entire study, which included Littman electronic, cardiology and classic. Data was evaluated for normality. Various statistical tests were used to evaluate the data including Chi‐squared and Fisher's exact test and Wilcoxon matched pairs signed rank tests using Graphpad Prism 8.3, Significance was determined at p < 0.05. Horses were aged between 5–23 years (13.8 ± 4.9) years. The distribution was 32% mares and 68% geldings. They were equally distributed between TB type (38%), ISH (33%) and cob (29%). The median weight was 620 kg (IQR600–650). Median body condition score was 6 (IQR5–6) and median heart rate was 36 beats per minute (IQR32–36). 20% of horses were found to have second degree atrio‐ventricular blockade and 17% had murmurs (50% systolic murmurs associated with the mitral valve and 50% physiological aortic flow murmurs). S4 was audible in 94% of horses and S3 in 78% of horses. S4 was most likely to heard in the left fourth intercostal space and S3 very ventral in the fifth left intercostal space. There was no effect of breed, body condition score, ambient noise level or hair length as to whether S3 or S4 were audible (Table 1). Lower heart rates increased the likelihood that S4 was audible (p = 0.01; S4 audible – 32(32–36) bpm and not audible 36(36–40)). Level of experience of cardiac auscultation improved the likelihood of hearing S3 (p = 0.03), but not S4 (p = 0.16). In summary, S3 is audible in many horses and not just thin, fit Thoroughbreds if auscultated in the optimal position and experience improves auscultation skills as has been previously reported.   ABSTRACT E05 Comparison of two‐dimensional versus three‐dimensional echocardiography for assessment of left atrial volume in thoroughbred racehorses Francesca C. Worsman; Karen Blissitt; Darren Shaw; John Keen The Royal (Dick) School of Veterinary Studies, University of Edinburgh Left atrial size predicts morbidity and mortality in human and small animal cardiology. In horses, assessing left atrial volume may be of particular interest for volume overload associated with conditions such as mitral valve regurgitation, atrial fibrillation, and ventricular septal defects. The aim of this study was to determine the intra‐observer measurement variability of equine left atrial volume using the modified Simpson's method of discs, and compare this to volumes obtained using a real‐time three‐dimensional software analysis package (4D LVQ, EchoPAC v 202, GE Healthcare). The study used graded datasets of the left atrium of athletic Thoroughbreds horses (n = 24; 4–9 yrs; 411–534 kg), obtained from right parasternal views using a Vivid E9 with 3 V transducer (GE Healthcare). Horses with grade > 3/6 cardiac murmurs assessed by auscultation were excluded from this study. Random generated order measurements were obtained by a single observer on 4 occasions. Two‐dimensional end‐systolic (2DE‐ESV) and end‐diastolic (2DE‐EDV) left atrial volumes were measured by a modified Simpson's method of discs, using the 2DE Volume Biplane function (EchoPAC v 202, GE Healthcare). Intra‐observer variability was assessed via calculation of 1 – the intra‐class correlation coefficient (ICC) from random‐effect linear models on EDV and ESV with horse added as the random effect (1 ‐ ICChorse) in R (v 3.5.2, R) using the lmer and sjPlot packages. Intra‐observer variability for the three‐dimensional measurements has been previously presented1 and was assessed via calculation of 1 – the intra‐class correlation coefficient. The same datasets were used for both measurements and comparison between two‐dimensional and three‐dimensional volumes were assessed using Bland Altman plots in R (v 3.5.2) using the BlandAltmanLeh package. Average 2DE‐EDV was 684 ml (range 440–1144 ml) while 2DE‐ESV was 404.4 ml (range 212–786 ml), n = 24. Lower observer variation (1 ‐ ICChorse) for 2DE‐EDV measurements was observed (25%) compared to 2DE‐ESV (38%). This suggests agreement between measurements (1 ‐ ICChorse <50%). Bland Altman analysis of two‐dimensional versus three‐dimensional volumes suggested a mean difference of −23.4 ml for 3DE‐ESV (lower limit CI −33, upper limit CI 290) (Figure 1), and − 90.9 ml for 3DE‐EDV (lower limit CI ‐469.5, upper limit CI 287.8) (Figure 2). Although volumes assessed from two‐dimensional and three‐dimensional datasets were comparable, assessment of left atrial volume using the modified Simpson's method showed greater intra‐observer variability and only moderate agreement between measurements, in comparison to the previously reported results for three‐dimensional volume assessment which suggested good agreement.1 Three‐dimensional techniques for assessing volume are likely to be preferable for longitudinal evaluation of left atrial volume owing to less variability. REFERENCE1. Worsman FCF, Blissitt K, Shaw DJ, Keen JA. Assessment and intra‐observer variability of equine left atrial volume using 4D Manual LVQ algorithm (GE Healthcare). ECEIM Congress Valencia 2019 Proceedings Abstract 74, 2019, page 85.   ABSTRACT E06 Influence of stethoscope on cardiac auscultation in the horse Gayle D. Hallowell; James Heale; Paul Lewis; James Bailey; Adam Redpath; Steffi Pratt School of Veterinary Medicine and Science, University of Nottingham The main objective of this study was to evaluate the impact that different stethoscopes have on the ability to auscultate the adult equine heart. 20 horses were auscultated by at least 5 individuals using nine different stethoscopes. Records were made regarding operator experience, body condition score, hair length, ambient noise level, breed type, heart rate, which heart sounds could be auscultated in the 4th and 5th left and right intercostal spaces. Any murmurs and dysrhythmias were also recorded. Users were also asked to give a preference score for each stethoscope per horse. Stethoscopes evaluated included various Thinklabs, Kruuse, Littman and MDF. Various statistical tests were used to evaluate the data including Chi‐squared and Fisher's exact test, Mann Whitney U test, Friedman test and Wilcoxon matched pairs signed rank tests using Graphpad Prism 8.3. Significance was determined at p < 0.05. Horses were aged between 5–23 years (13.8 ± 4.9) years. The distribution was 32% mares and 68% geldings. They were equally distributed between TB type (38%), ISH (33%) and cob (29%), The median weight was 620 kg (IQR600–650). Median body condition score was 6(IQR5–6) and median heart rate was 36 beats per minute (IQR32–36). 20% of horses were found to have second degree atrio‐ventricular blockade and 17% had murmurs (50% systolic murmurs associated with the mitral valve and 50% physiological aortic flow murmurs). The electronic stethoscopes and one of the Littman stethoscopes were superior regarding audibility of S4 (p = 0.04) and S3 (p = 0.03). Grading of murmurs was higher when the electronic and cardiology stethoscopes were used, compared to others (p = 0.02). All users reported that their preference was influenced by how easy it was to hear heart sounds on the right. All stethoscopes had similar preferences, except for the MDF, which was the least preferred (p = 0.04). There was a wide range in preferability of the electronic stethoscopes between users and horses that was related to how long the haircoat was (p = 0.01) and ambient noise level (p = 0.03). Preferred stethoscope within users was related to what they were used to using. Overall the electronic stethoscopes increased the ability to hear heart sounds and those and the cardiology stethoscopes allowed for improved auscultation of murmurs. The electronic stethoscopes were less good in noisier environments and on hairier animals. ABSTRACT E07 Effects of short‐term induced atrial fibrillation on atrial function after cardioversion Charlotte Hopster‐Iversen 1 ; Rikke Buhl2; Helena Carstensen2; Sanni Hansen2; Eva Hesselkilde2; Sarah Nissen2 1Faculty of Health and Medical Sciences, University of Copenhagen; 2University of Copenhagen Atrial fibrillation (AF) causes electrical and contractile remodeling in horses. Aim of this study was to evaluate the effects of short‐term induced AF on left atrial contractile function after spontaneous cardioversion. Nine healthy standardbred horses were included. The right atrium was tachy‐paced (600 bpm) for 20 hours to simulate AF. Echocardiographic evaluation of the left atrium (LA) was performed before induction of AF (T0) and immediately after cessation of the atrial pacing and spontaneous conversion to sinus rhythm (T1). The echocardiographic measurements included LA diameter, area and ejection phases indices. Atrial TDI (Tissue Doppler Imaging) measurements included peak myocardial velocity during atrial contraction (A), time to onset A (onset A), time to peak A (tA) and duration of A (durA). Short‐term simulated AF resulted in significantly reduced atrial contractile function (active fractional area change of the LA and ratio of active‐to‐total LA area change) and prolonged TDI‐based conduction time (onset A) at T1 compared to T0. Previous studies in horses with naturally occurring AF have shown atrial electrical and contractile remodeling compared to horses in sinus rhythm with a gradual improvement over time after cardioversion. The present study demonstrated reduced atrial function when the horses returned to sinus rhythm already after just 20 hours of tachy‐paced AF. This highlights the importance of rapid treatment of AF in order to prevent contractile remodeling of the atria and avoid possible negative effects on the long‐term prognosis for sustained sinus rhythm. ABSTRACT E08 Can the frequency of vagally‐mediated arrhythmias after conversion predict atrial fibrillation reoccurrence in horses? Melodie J. Schneider; Katharyn Mitchell; Colin Schwarzwald University of Zurich Reoccurrence of atrial fibrillation (AF) after cardioversion is a common problem in horses, with recurrence rates of 16–50% reported. Known predictors of reoccurrence include previous episodes of AF, left atrial (LA) enlargement, atrial stunning after conversion, mild or greater mitral regurgitation and >4 mth duration of AF. In human medicine, highly vagal individuals (particularly extremely fit athletes) have a 3‐fold increase in the risk of developing AF through vagally‐mediated electrophysiology mechanisms such as shortened atrial effective refractory period and action potential duration. This study aimed to examine the relationship between atrioventricular blocks (AVB) detected in 24 hr ECG recordings after successful cardioversion of AF and the rate of reoccurrence of AF. The medical records for all AF cardioversions between 2007–2019 were examined and information about AF reoccurrence collected. Three 24 hr ECG recordings (0–24, 24–48 and 48–72 hr periods after conversion) were analyzed for the frequency of arrhythmias. Two‐way, repeated measures ANOVAs were performed to compare the number of arrhythmias in horses with and without AF reoccurrence. A Chi‐squared test was used to evaluate the effect of LA enlargement and treatment on AF reoccurrence. Twenty‐one horses underwent 24 successful conversions (12 with quinidine sulfate, 12 with transvenous electrical cardioversion) during this period. At follow‐up, 10 horses were in normal sinus rhythm (48%), 9 horses were in AF (43%) and 2 horses were lost to follow up. The median number of AVB per 24 hr recording period was 60 (min 0–max 4905). There was no difference in the number of AVB/24 hr period in horses with and without reoccurrence of AF (p = 0.51). There was a median of 27 atrial premature complexes (APCs) per 24 hr recording period (min 2–max 1417). No difference between the number of APCs/24 hr period in horses with or without AF reoccurrence was observed (p = 0.27). Horses with LA enlargement had a higher rate of reoccurrence (reoccurrence rate 80% vs. 36% with no LA enlargement, p = 0.04). There was no difference in the rate of reoccurrence between the two treatments (p = 1). In this cohort of horses with AF, there was no association between the frequency of AVBs or APCs in the immediate (0–72 hr) post conversion period and the reoccurrence of AF. This study is limited by the small sample size. ABSTRACT E09 New diagnostic opportunities for diagnosing paroxysmal atrial fibrillation in horses Rikke Buhl; Sarah Nissen; Helena Carstensen; Sofie Poulsen; Marie Louise Winther; Charlotte Hopster‐Iversen; Thomas Jespersen; Eva Hesselkilde University of Copenhagen In equine cardiology, only limited information about paroxysmal atrial fibrillation (PAF) is available and undiagnosed PAF could be related to poor performance in horses. Due to the intermittent occurrence, PAF is difficult to diagnose, however by implanting a small ECG device (Implantable loop recorder, ILR) subcutaneously automatic detection of PAF can be obtained. The aim of the study was to investigate if ILRs were able to detect PAF in poor performing horses and how reliable the method was. Twelve Standardbreds (mean age 6 years (range 3–8 years)) with a history of reduced performance were recruited from the racetracks. After cardiac examination, an ILR (Reveal Linq, Medtronic) was inserted subcutaneously at the sixth left intercostal space after local anesthesia. After implantation, the horses were trained and raced with no restrictions. The ILRs were read at various time points. The mean period of ILR implantation was 6.5 months (range 2–24 months). In three horses, PAF was detected with a mean duration of 7 hours (range 1 hour 36 min–10 hours 5 min, in total five episodes). Furthermore, one horse had persistent AF detected by the ILR. The ILR detected marked sinus arrhythmia in three horses. Overall, the ILRs were able to detect correct heart beats in 95% with 5% misclassifications. The algorithm had a positive detection in 85% and a false detection in 15% of the AF episodes. No episodes were recorded during exercise, due to movement artifacts. Surprisingly, PAF was detected in three out of 12 horses, suggesting that PAF may occur more frequently in the horse population than previously expected. Therefore, ILRs can be a useful ECG tool for horses presented with poor performance. As no episodes were recorded during exercise, we cannot conclude whether PAF also occurs during physical activity. ABSTRACT E10 Phenotypic and functional characterization of equine endothelial cells Elizabeth J. Finding; Robert Purcell; Nicola Menzies‐Gow; Jonathan Elliott; Caroline Wheeler‐Jones Royal Veterinary College Endothelial cells are ubiquitous and universally useful, but isolation without proper identification can lead to data misinterpretation. Studies making use of equine endothelial cells (EC) include those exploring viruses (e.g., EHV), laminitis and inflammation but investigation of equine EC is also relevant to wound healing, regenerative medicine and exercise physiology, areas that have received little attention to date. Although equine EC have been used in scientific research since 1985 there is limited information on the in vitro biology of these cells. This study characterizes equine aortic endothelial cells (EAEC), providing the essential information for researchers to study these cells with confidence. EAEC were isolated from mixed breed adult horses euthanased at a commercial abattoir using collagenase digestion (0.25 mg/ml; 10–20 mins) or mechanical scraping. Cells were cultured on gelatin‐coated tissue culture flasks in Medium 199 (M199) supplemented with 20% equine serum, endothelial cell growth factor, heparin and antibiotics, or in Endothelial Cell Growth Medium 2 (ECGM2; Promocell) supplemented with 20% equine serum and antibiotics. Cells were visualized using phase contrast light microscopy and fluorescent immunocytochemistry (ICC). ICC results were validated using en face imaging of equine intercostal arteries. EAEC angiogenic potential was investigated using a thin layer 2‐dimensional angiogenesis assay (TLA). Intracellular signaling responses to treatment with vascular endothelial growth factor (VEGF; 1–100 ng/ml; 1–60 min) were investigated using Western blotting to detect phosphorylation of extracellular signal‐regulated kinase 1 and 2 (ERK 1/2). Equine blood outgrowth cells (eBOC) from healthy horses were isolated by culturing fresh peripheral blood monocytic cells (PBMC) on collagen using equine‐specific reagents and a standard protocol in use for human blood outgrowth EC isolation (also known as endothelial cell colony forming cells; ECFC). eBOC colonies were observed 11–15 days after initiation of PBMC culture. Colonies of more than 100 cells were passaged and propagated on collagen‐coated plates prior to analysis by ICC, flow cytometry and immunoblotting. Human ECFC were isolated and characterized in parallel. Mechanical scraping yielded a higher proportion (80%; n = 30) of EC‐rich cultures (>60% vWF‐positive cells) than collagenase digestion (33%; n = 27; p = 0.0005). EAEC growth rate was greater in ECGM2 than M199 (2.5 ± 1.2 cells/h vs. 17.3 ± 1.2 cells/h; n = 1; p < 0.0001). The endothelial nature of EAEC was confirmed by immunostaining for von Willebrand factor (vWF), with cells displaying punctate staining suggestive of vWF storage within Weibel‐Palade bodies. This distribution was also seen in en face preparations. Other antibodies raised against EC‐specific or EC expressed proteins did not cross react with EAEC antigens in ICC in unstimulated cells or in cells exposed to inflammatory cytokines; these include CD31, CD34, CD105, VE‐cadherin, VEGFR2, ICAM‐1, ICAM‐2, VCAM‐1, claudin 5 and ZO‐1. EAEC tubulogenesis, assessed using the TLA, was increased in response to VEGF but performance of the assay varied between cells cultured in M199 or ECGM2. Treatment with VEGF resulted in phosphorylation of ERK1/2 with a maximal response at 25 ng/ml and after 5, 10 and 30 minutes incubation. Human ECFC displayed typical EC cobblestone morphology, expressed EC markers (e.g., CD31; vWF, VE‐cadherin) and displayed VEGF‐stimulated tubulogenesis in the TLA assay. In marked contrast, eBOC cultures (n = 8) had a fibroblastic morphology, expressed typical mesenchymal stromal cell (MSC) markers (CD29, CD44, CD90, CD105) and failed to form tube‐like structures in the TLA assay. This study provides the initial essential information necessary for detailed cell biology studies of EAEC. Not all previous studies using equine vessel EC or purporting to have isolated equine ECFC have confirmed the endothelial identity of the cell population isolated. The level of contamination evident in some EAEC cultures raises concerns that results from studies without EC identification are representative of a mixed vascular cell population, rather than a specific endothelial population. One major challenge facing equine EC research is the lack of commercially available equine‐specific antibodies for endothelial antigens. Despite thorough investigations, the only EC‐specific protein reliably detected was vWF. This is an essential antibody to identify EC but it cannot be used to purify cells from a mixed population; this would require an antibody targeted to a cell surface antigen. Preliminary investigations of the angiogenic functions of EAEC have been performed, including assessment of VEGF signaling, to provide a framework for further studies. The difficulties associated with isolation of equine ECFC from PBMC cultures means that rigorous characterization of equine vascular EC models is critical for progressing understanding of equine endothelial cell biology. ABSTRACT E17 Poincaré plots as a visual measure of heart rate variability in healthy horses Katharyn J. Mitchell; Michaela Kuehni; Colin Schwarzwald University of Zurich Poincaré plots are graphical displays of heart rate variability (HRV) that are used in ECG analysis. Although regularly utilized in human and small animal cardiology, these graphical analyses are not well described in horses. This study aimed to define Poincaré patterns in overnight ECG recordings from healthy horses and assess between‐day variability in Poincaré patterns in a subset of horses. Overnight ECG recordings were obtained from 30 healthy horses. Five horses had three ECGs recorded. The ECGs were corrected for artifacts. Arrhythmias were noted but not removed from the data set. Percent instantaneous beat‐to‐beat cycle length variation (% R‐R variation) was calculated, Poincaré plots were created and traditional HRV analyses performed. The mean (min, max) recording length was 11 hrs 32 min (10 hrs 18 min, 13 hrs 21 min). Atrioventricular (AV) blocks, sinus pauses or both were present in 27 horses. Five horses showed frequent (>1/hr) atrial or ventricular premature complexes and were separated from the remaining analyses. The maximum % R‐R variation was between −57.9 and 133.2%, with the median variation −0.2%. Evaluation of the Poincaré plots revealed healthy horses to have a comet or wedge pattern with RR intervals sequences containing second‐degree AV blocks and sinus pauses/blocks appearing as clusters in the upper and lower right quadrants. Premature complexes appear as clouds in the lower left, upper left and middle‐lower right quadrants. Repeatability of the Poincaré patterns was excellent, with most variables showing very low‐low variability (coefficients of variation between 3.8 and 28.5%). Poincaré plots as graphical representations of HRV allow the observer an immediate overview of the cardiac rhythm patterns during the period of recording. The pattern of overnight equine Poincaré plots appears similar to those of resting humans but quite different to those reported in dogs. This difference is postulated to relate to the marked respiratory sinus arrhythmia observed in canines. Overnight ECG recordings have excellent between‐day repeatability and provide very similar Poincaré patterns. ABSTRACT E18 Novel mobile applications enable wearable devices to yield accurate exercising ECG and heart rate data in horses Joanne E. Haughan 1; Noah Cohen2; Mary Robinson3; Cristobal Navas de Solis3 1Department of Clinical Studies, University of Pennsylvania School of Veterinary Medicine, New Bolton Center; 2College of Veterinary Medicine & Biomedical Sciences, Texas A&M University; 3University of Pennsylvania School of Veterinary Medicine, New Bolton Center User‐friendly tools are needed to investigate sudden cardiac death in horses. We hypothesized wearable devices would provide diagnostic‐quality electrocardiograms (ECGs). ECGs obtained with 2 wearable devices (W2nd™ and Polar Equine™) were compared to simultaneous recordings with a telemetry unit (Televet™) in 5 Thoroughbreds completing 43 separate submaximal exercise tests on a treadmill. Voltage data were generated by mobile applications and analyzed using Kubios software by 1 blinded investigator. Televet recordings were analyzed routinely. Maximal heart rate (HR) generated by mobile applications (HRmaxapp), HR after manual correction (HRmaxcorr), percentage diagnostic ECGs (%diag) at the gallop, and overall quality assessed by visual analogue scale (VAS) were compared. Statistical analysis was performed using linear mixed‐effects modeling, chi‐squared tests, and Bland‐Altman plots. Significance was set at p < 0.05. Acceptable %diag was defined as >95%/ECG and a priori limits of agreement for HRmax were set as ±2.5% maximal HR. HRmaxcorr did not differ between groups. HRmaxapp was significantly lower for W2nd (166.8/min, 95% CI: 160.5–173.1/min) but did not differ significantly between Televet (178.8/min 95% CI:165.8–191.1/min) and Polar (181.3/min, 95% CI:174.5–188.1/min). HRmaxcorr was accurate and precise in all runs but HRmaxapp was within a priori limits of agreement in 16/23 W2nd and 18/19 Polar recordings. %diag was significantly lower (77.1%, 95% CI:67.4–86.8) for W2nd than Polar (100%, 95% CI:89.9–110.3). VAS was lower for W2nd (46.2, 95% CI:35.5–57.0) than Polar (90.6, 25% CI:79.4–101.9) and Televet (82.8, 95%CI:74.0–91.5). Wearable devices are promising tools for large scale studies of exercising arrhythmias in horses. ABSTRACT E19 Plasma and urine aldosterone in normal horses and horses with subclinical valve disease Babetta A. Breuhaus North Carolina State University College of Veterinary Medicine The renin‐angiotensin‐aldosterone system (RAAS) is activated in heart failure to support arterial blood pressure. However, chronic activation of RAAS becomes maladaptive, potentially causing myocardial injury and fibrosis. Horses with heart disease are sometimes treated with angiotensin‐converting inhibitors; however, benefits of therapy are theoretical and cost‐effectiveness uncertain. Accordingly, we attempted to measure when RAAS is activated in horses with cardiac disease. A commercially‐available assay for plasma and urine aldosterone concentrations was evaluated in 22 healthy horses, and in 30 horses with chronic, valvular heart disease (VHD) due to mitral or aortic regurgitation. Diagnoses were based on clinical examination and Doppler echocardiography. Blood and urine samples were obtained from all horses and stored for quantitation of aldosterone and creatinine concentrations. Percent recovery, intra‐ and inter‐assay coefficients of variation were acceptable. Preliminary reference intervals were established in normal horses using CLSI robust statistical methods. Median (upper confidence limit) concentrations of plasma and urine aldosterone were 254 (1058) and 7890 (18007) pmol/L, while urine aldosterone:creatinine ratio (UA:C) was 745.3 (UCL = 1672.6) pmol/mmol. Accepting the limitations of a small sample for generating relatively wide reference ranges, aldosterone concentrations were not increased in horses with VHD, including subanalysis of 16 with increased left heart size. Plasma aldosterone was weakly correlated to UA:C (r2 = 0.231, p < 0.001). These preliminary results suggest that RAAS is not continually active in some horses with subclinical VHD, even when there is cardiac enlargement. Further studies in horses should focus on those with heart failure and specific preclinical stages of VHD. ABSTRACT E20 Seasonal variation of endogenous adrenocorticotropic hormone (ACTH) in healthy non‐geriatric donkeys in Northern California Sarah Schale 1; Erin Goodrich2; Philip Kass1; Emily Berryhill1 1University of California Davis; 2Cornell University Background: Elevated plasma adrenocorticotropic hormone (ACTH) is often used to diagnose pituitary pars intermedia dysfunction (PPID) in horses. The hormone is known to naturally increase in the fall season in horses. Donkeys have been found to have higher ACTH concentrations than horses, however, variation of ACTH concentrations over a 12‐month period has not been assessed. Hypothesis: We hypothesized that donkey ACTH concentrations would be higher than horses in all seasons, and that, similarly to horses, ACTH concentrations would further increase in the fall. Animals: 25 healthy donkeys (10 standards, 15 miniatures), a median (range) of 6 (2–13) years of age, and at the same location under the same management. Methods: Prospective observational study. Serial plasma samples obtained bimonthly from June through November and monthly from December through May. Plasma ACTH concentrations were determined by a validated assay. Data are presented as medians with lower and upper 95% confidence intervals (95% CI). Results: Donkey ACTH concentrations were lowest in the winter and spring (12.6 [9.7–15.5] pg/mL and 19.0 [16.5–21.5] pg/mL, respectively), with an increase in the summer (52.9 [45.5–60.3] pg/mL), and peak in the fall (77.2 [64.5–89.7] pg/mL). Fall concentrations were higher than those in spring and winter (p‐value <0.0001). ACTH concentrations were highest in September (123.0 [95.4–150.4] pg/mL). Conclusion and clinical importance: Donkey ACTH concentrations were similar to normal concentrations reported in horses in winter and spring but were higher in summer and fall, with a marked increase in fall. Donkey‐specific reference ranges are required for accurate endocrinopathy screenings. ABSTRACT E21 Androgens and estrogens in healthy and hospitalized neonatal foals Jacob M. Swink 1; Lindsey Rings2; Hailey Snyder1; Katarzyna Dembek3; Ahmed Kamr1; Nimet Browne4; Katherine Christie2; Ramiro Toribio1 1The Ohio State University; 2Rood and Riddle Equine Hospital; 3Iowa State University; 4Hagyard Equine Medical Institute Sepsis and neonatal maladjustment syndrome (NMS) are major causes of morbidity and mortality in neonatal foals. Dysfunction of the hypothalamic‐pituitary‐adrenal axis is frequent in critically ill newborn foals. Some information is available on glucocorticoids, mineralocorticoids, and progestogens in healthy and sick foals, but little is known about androgens and estrogens. High progestogens have been associated with sepsis and NMS. The goal of the study was to measure androgens and estrogens in hospitalized foals. Blood was collected on admission (0) and at 24, 48, and 72 hours from 62 healthy, 56 septic, and 41 sick non‐septic (SNS) foals of <3 days of age. Serum androgens and estrogens were measured using immunoassays. At admission, estrone sulfate, androstenedione, and testosterone concentrations were higher in septic compared to healthy and SNS foals (p < 0.05). Estradiol, estrone sulfate, testosterone, dehydroepiandrosterone (DHEA), and androstenedione were higher in foals with evidence of NMS (p < 0.05). Testosterone, estrone sulfate, and estradiol were higher in non‐surviving foals (p < 0.05). All hormones decreased over time in healthy foals but remained elevated in septic foals. Foals with higher testosterone concentrations were more likely to die. The areas under the curve for estradiol, estrone, dihydrotestosterone (DHT), androstenedione, and DHEA were good predictors of non‐survival. This study showed that androgen and estrogen concentrations are altered in sick foals and their dynamics during hospitalization are associated with disease severity and outcome. Increased sex steroid concentrations likely reflect delayed clearance and organ dysfunction. Some of these steroids may have prognostic value. ABSTRACT E22 Effect of altrenogest administration to pregnant mares on the endocrine profile of their foals Jacob M. Swink 1; Lindsey Rings2; Hailey Snyder1; Rachel McAuley1 ; Katarzyna Dembek3; Michele Frazer4; William Gilsenan2; Ramiro Toribio1 1The Ohio State University; 2Rood and Riddle Equine Hospital; 3Iowa State University; 4Hagyard Equine Medical Institute Sepsis remains the leading cause of mortality in newborn foals. Critical illness alters the hypothalamic‐pituitary‐adrenal axis in newborn foals. Administration of exogenous progestogens (altrenogest, progesterone) is common practice in the equine industry. Exogenous steroids cross the placental barrier and elevated endogenous progesterone concentrations have been associated with illness in newborn foals. Therefore, the goal of this study was to determine the association between altrenogest administration to pregnant mares and the steroid profile/disease status of their foals. Blood samples were collected on admission from 62 healthy, 56 septic, and 41 sick non‐septic (SNS) foals of <3 days of age. Foals within groups were further divided into born to altrenogest‐treated or ‐untreated mares. Serum progesterone, 17α‐hydroxyprogesterone, pregnenolone, dehydroepiandrosterone (DHEA), allopregnanolone, and cortisol, and plasma adrenocorticotropic hormone (ACTH) were measured using immunoassays. Altrenogest‐exposed septic foals had lower ACTH and 17α‐hydroxyprogesterone, but higher progesterone than unexposed foals (p < 0.05). Altrenogest‐exposed non‐surviving foals had higher pregnenolone and progesterone concentrations than those from untreated‐mares (p < 0.05). Allopregnanolone, cortisol, DHEA, or ACTH:steroid ratios were not different between exposed and unexposed foals. Hormone levels between exposed and unexposed foals within healthy, SNS, surviving, or NMS groups were not different. Altrenogest exposure was not associated with likelihood of mortality. This study demonstrates that exogenous progestogens could influence the steroid profile of septic newborn foals. Progestogen difference between septic altrenogest‐exposed and unexposed foals does not imply a cause of disease, but an association, which due to its implications deserves additional controlled studies before these findings are extrapolated. ABSTRACT E23 The effect of trailering and dentistry on resting adrenocorticotropic hormone concentration in horses John C. Haffner 1; Steve Grubbs2; Rhonda Hoffman3 1Middle Tennessee State University Horse Science Center; 2Boehringer Ingelheim; 3Middle Tennessee State University Pituitary pars intermedia dysfunction (PPID) may affect >20% of horses aged ≥15 years. The measurement of adrenocorticotropic hormone (ACTH) is the most commonly used diagnostic test used for the diagnosis of horses with PPID. The diagnosis of PPID is supported by a plasma ACTH concentration greater than the seasonally adjusted reference range. However, several studies have concluded that pain, stress and concurrent illness were only likely to affect diagnostic usefulness of resting ACTH when severe. The objective of this study was to identify if trailering or teeth floating (common stressful situations/procedures) increased plasma ACTH concentrations in horses. Twelve horses were enrolled and randomized into 3 groups of 4 horses/group. Each horse group was randomly assigned to the initial treatment group, dentistry (DN), trailered (TR) or stabled controls (CN). Following initial treatment, each horse group was randomly assigned to each of the two remaining treatment groups; therefore, each horse group underwent all 3 treatments. Plasma was collected from all horses prior to each treatment (baseline). The DN horses were placed in stocks, sedated with 0.1 to 0.3 mg/lb xylazine IV and following mouth speculum placement, teeth were floated with a PowerFloat®. The TR group was loaded on a six‐horse slant trailer and hauled for 40 minutes. Immediately following the dental procedure and trailer ride, post‐procedure (P0) plasma samples were collected. Plasma samples were then collected from all horses at 15, 30, 60 and 120 minutes post‐procedure. Plasma samples from the CN horses were taken when the trailered horses returned. Plasma samples were frozen (−80C) until analysis at Cornell Animal Health Diagnostic Center. Data were analyzed using a mixed model with repeated measures (i.e., each horse as its own control), with main effects of treatment (CN, DN, TR) and time, and day x time as the repeated effect. Statistical significance was designated at p < 0.05, and 0.05 < p < 0.10 was considered a trend. Data were summarized as mean ± SE. No change occurred in ACTH over time in the CN or DN horses (p = 0.14). ACTH was higher in TR compared to CN (p = 0.026) and DN (p = 0.016) horses. In TR horses, ACTH was higher than baseline (PRE) immediately after (T0; p = 0.0003) and tended to be higher (p = 0.066) at 15 min after trailering. By 30 min post‐trailering, there were no differences in mean resting ACTH compared to PRE concentrations (p = 0.55). No significant difference in resting ACTH concentrations over time was observed in horses undergoing dentistry procedure compared to baseline. A forty‐minute trailer ride resulted in significantly increased resting ACTH concentrations in horses up to 30 min post‐unloading. Based on results of this study, collecting blood from horses within 30 minutes from trailer unloading may result in elevated resting ACTH concentrations. ABSTRACT E37 Diagnostic evaluation of insulin and glucose dynamics in light breed horses with experimentally‐induced insulin dysregulation Kathryn Timko; Laura Hostnik; Mauria Watts; Chiaming Chen; Adam Bercz; Ramiro Toribio; James Belknap; Teresa Burns The Ohio State University Insulin dysregulation (ID) increases the risk for developing laminitis and other metabolic derangements. Therefore, proper identification of horses with ID is important to facilitate preventive treatment strategies. This study compared three diagnostic tests for ID: baseline insulin (BI) and glucose concentrations, oral sugar test (OST), and combined glucose and insulin test (CGIT) in horses before and after induction of ID. Fourteen adult light breed horses received dexamethasone (0.08 mg/kg PO q 24 h; 7 days) to induce ID. BI, OST, and CGIT were evaluated before and after ID. Observed agreement and kappa coefficients were calculated for BI, OST and CGIT for the diagnosis of ID. Proxy measurements of ID (reciprocal of the square root of insulin [RISQI], quantitative insulin sensitivity check index [QUICKI], homeostasis model assessment [HOMA] and insulin‐to‐glucose ratio [IG]) were calculated. Dexamethasone administration significantly changed the classification of horses from normal to ID based on BI, OST, and CGIT (p = 0.0013, 0.0128, 0.0006 respectively). RISQI, QUICKI, HOMA and IG were all significantly different after dexamethasone administration. There was moderate agreement between BI and OST [ins]60 > 60 μIU/mL, BI and [ins]60 > 45 μIU/mL and between BI evaluations performed 24 hours apart (k = 0.512, 0.435, 0.444 respectively). There was poor agreement between BI and CGIT using diagnostic criteria for insulin and glucose (k = −0.026, 0.122 respectively). All tests and proxy measurements supported induction/exacerbation of ID after dexamethasone treatment. The variability in diagnostic performance of common tests for equine ID may affect clinical decisions; performing multiple tests may improve accuracy. ABSTRACT E38 Effect of early or late sampling on thyrotropin‐releasing hormone (TRH) stimulation test results Kristen Thane 1; Nicholas Frank1; Amy Rubin2; Cassandra Uricchio2 1Tufts University; 2University of Massachusetts Diagnosis of pituitary pars intermedia dysfunction (PPID) using the thyrotropin‐releasing hormone (TRH) stimulation test requires precise timing from injection of TRH to blood sample collection. The objective of this study was to determine whether early or late sampling would result in a significant (>10%) difference in plasma adrenocorticotropic hormone (ACTH) concentration compared to standard 10‐minute sampling. Sixteen healthy adult horses with unknown PPID status underwent a single TRH stimulation test, with blood aseptically collected into EDTA vacuum tubes immediately prior to TRH injection and exactly 9 minutes (early), 10 minutes (standard), and 11 minutes (late) post‐injection. Blood was processed within 4 hours of collection; plasma was stored at −20C until analysis and ACTH was measured by chemiluminescent immunoassay. Two aliquots of each 10‐minute plasma sample were analyzed separately to assess intra‐assay variability. Minor variability was observed between the paired 10‐minute sample aliquots (range 0.0% to 5.0%; median 2.3%). Both early and late samples exhibited greater variability compared to the average of the paired 10‐minute samples, and overall variability of early or late samples compared to the corresponding 10‐minute mean concentration ranged from 0.1% to 62.7% (median 10.3%). Seventy‐five percent of horses tested had at least one early or late reading that differed by >10% from its corresponding 10‐minute mean value. Incidence of >10% variability was independent of PPID status. Precise timing of sample collection is critical to ensure accurate assessment of PPID status given the observation of significant variability associated with minor alterations in sample collection timing. ABSTRACT E39 Cartilage oligomeric matrix protein differential expression in lamellar tissue from prolonged euglycemic hyperinsulinemic clamp model Sarah F. Colmer 1; Andrew Van Eps2; Hannah Galantino‐Homer1 1University of Pennsylvania School of Veterinary Medicine; 2University of Pennsylvania School of Veterinary Medicine, New Bolton Center Endocrinopathic laminitis (EL) is one of the most common forms of equine laminitis, although its precise pathogenesis remains to be discovered. The euglycemic hyperinsulinemic clamp (pEHC), implemented by intravenous continuous rate infusion of insulin while plasma glucose concentrations are held constant at basal levels by glucose infusion, induces laminitis and epidermal lamellar lesions in both fore and hind limbs. In addition, distal limb cooling prevents pEHC laminitis and epidermal lesions in the cooled limb. However, little is known about dermal tissue damage in EL. Cartilage oligomeric matrix protein (COMP) serves as a marker of damage or degradation of collagen in connective tissue (cartilage, tendon, or dermis). The objective of this study was to determine if COMP is reduced in lamellar tissue from the pEHC model and if cryotherapy prevents COMP loss and dermal lamellar damage. COMP was quantified through immunoblotting and densimetry of protein extracts from snap‐frozen lamellar tissue from a cooled forelimb and ambient fore and hind limbs from 8 young Standardbred horses subjected to 48 hours of pEHC. A statistically significant decrease in COMP was identified in extracts from both the ambient forelimbs (p < 0.001) and hind limbs (p < 0.001) compared with cooled forelimbs. These results suggest that dermal damage contributes to EL pathogenesis in both forelimbs and hind limbs and that it can be prevented by cryotherapy.   ABSTRACT E41 Assessment of clinical and microbiota responses to fecal microbial transplantation in horses with diarrhea Caroline McKinney 1 ; Daniela Bedenice1; Ana Pacheco2; Bruno Oliveira3; Mary Rose Paradis1; Melissa Mazan1; Giovanni Widmer1 1Cummings School of Veterinary Medicine at Tufts University; 2Carlson College of Veterinary Medicine at Oregon State University; 3Universidade Estadual Paulista (Unesp), Faculdade de Medicina Veterinária Fecal microbial transplantation (FMT) is empirically employed in horses with colitis to facilitate resolution of diarrhea. The study purpose is to investigate the clinical response and fecal microbial profile of diarrheic horses treated at two university hospitals, with FMT (location‐1) or without FMT (location‐2), and to test whether FMT restores microbiota diversity. This prospective study included 23 horses with moderate to severe diarrhea, consistent with colitis. FMT was only performed at location‐1 (n = 13), administering 2 lb feces from the same healthy donor to each patient for 3 consecutive days via nasogastric tube. Fecal samples were collected from both donor and recipient prior to each FMT and from recipients 24 hours following the last treatment (day 4). Four consecutive daily fecal samples were obtained from diarrheic horses at location‐2 (n = 10, without FMT) and 10 healthy horses to serve as controls. The fecal bacterial microbiota profile was characterized using 16S amplicon sequencing. The fecal microbiota of horses with colitis was significantly more variable (higher β‐diversity) compared to healthy horses at both locations, with a phylogenetically similar microbiota among all healthy horses. A statistically comparable number of FMT recipients (7/13, 54%) and untreated horses (3/10, 30%, p = 0.253) developed a microbiota that more closely resembled the donor or healthy control, respectively. However, FMT recipients achieved a greater reduction in average diarrhea score (median: 4 grades), compared to untreated horses (median: 1.5 grades, p = 0.03). While FMT may improve diarrhea score in horses with colitis, the potential effect on microbiota restoration requires expanded analysis and sample size. ABSTRACT E42 The bioavailability and efficacy of a novel omeprazole product in horses Jessica Wise; Kristopher Hughes; Sharanne Raidal Veterinary Clinical Centre, Charles Sturt University Omeprazole facilitates gastric ulcer healing through the suppression of gastric acid secretion. Enteric‐coated omeprazole formulations have increased bioavailability; however, optimal dose rates of these preparations remain uncertain. The current study compared the bioavailability and efficacy pharmacodynamics of a novel, in‐feed, enteric‐coated granule formulation of omeprazole (NOV) with an existing, registered enteric‐coated paste formulation (REF). Bioavailability was assessed by comparison of plasma concentrations of omeprazole following administration of a single dose of NOV and REF, with intravenous administration of omeprazole. The study included 9 horses randomly assigned to a three sequence, three period Latin square design, with a 7 day wash out period. Efficacy was assessed by comparison of plasma omeprazole concentrations, gastric pH and ulcer scores following repeated administration of NOV or REF to 12 horses for seven days in a prospective two period, blinded and randomized trial with sequential cross over. The median bioavailability of NOV was 58.2% (range: 11.0–91.1) and for REF was 21.6% (range: 10.1–82.6); there was no significant difference between products (p = 0.312). Treatment was associated with increased gastric pH (p < 0.001) and reduced squamous ulcer scores (p < 0.001). There was no difference in gastric pH or squamous ulcer scores between omeprazole products. For both omeprazole products, treatment resulted in increased gastric pH (p ≤ 0.001). There was no difference in gastric pH profiles between products. Omeprazole treatment was associated with decreased gastric emptying. These results demonstrate good bioavailability and efficacy of the in‐feed omeprazole formulation indicating, supporting the use of this method of drug administration in horses. Our results also indicate that plasma concentrations of omeprazole and drug dose used do not predict drug efficacy. ABSTRACT E43 Inter‐observer agreement and intra‐observer repeatability of two scoring systems for equine gastric ulcer syndrome Jessica Wise; Sharanne Raidal; Kristopher Hughes Veterinary Clinical Centre, Charles Sturt University Clinical grading systems require good inter‐observer agreement and intra‐observer repeatability. A reliable scoring system for equine gastric ulcer syndrome (EGUS) would optimize ulcer scoring, including the effects of treatment and management protocols on ulcer healing, and comparison of results between studies. Six observers (three equine medicine specialists, three residents in equine disciplines) graded 60 pre‐recorded de‐identified equine gastroscopy videos, using two grading systems applied three times: the EGUS Council grading system and a novel visual analogue scale (VAS). There was a minimum period of one week between each grading occasion. The order of videos was randomized for each grading. Agreement coefficients were calculated using Gwet's agreement coefficient, with ordinal weights applied (AC2), for the EGUS Council grading system and the Intraclass Correlation Coefficient (ICC) for the VAS. Inter‐observer agreement was poor for both squamous (mean AC2 = 0.687) and glandular mucosa (mean AC2 0.721) using the EGUS grading system. The intra‐observer repeatability of the squamous (mean AC2 0.801) and glandular mucosa (mean ICC = 0.804) was acceptable for five observers. Inter‐observer agreement was poor for both squamous (mean ICC = 0.353) and glandular mucosa (mean ICC = 0.635) grading, using the VAS. The intra‐observer repeatability for squamous mucosa was acceptable for all experienced observers (mean ICC = 0.828. The intra‐observer repeatability for glandular mucosa was poor for all observers (mean ICC 0.555). These results indicate that agreement between observers is poor for grading of both squamous and glandular mucosal appearance, irrespective of the grading system used. Intra‐observer repeatability is influenced by grading system used and observer experience. These findings have implications for comparison of results between observers and studies and selection of grading system for monitoring of horses with EGUS. ABSTRACT E44 Complications of cecal decompression in horse with colic in a referral practice Aude Giraudet; Maxime Arpentinier Equine Clinic ENVA Cecal decompression is a routine procedure in many countries in Europe on horses presenting severe cecal distension. There is still much debate about the risks of such a procedure and the questions about its usefulness. From 2007 and 2019, 62 adult horses underwent cecal decompression during their colic examination or treatment in our institution. Number of procedure performed and complication and outcome were analyzed. Surgical versus non surgical treatments and outcome were compared. The repartition in age and breed of the 62 horses was similar to our general population, age and gender as well. Some horses were trocarized more than once, over the 73 cecal decompression performed 95% of them led to gas exteriorization. Over the surviving horses (63%) no abscess, nor focal cellulitis, nor peritonitis were observed (localized complications). One horse did die of uncontrolled internal hemorrhage following the procedure. Clotting abnormalities were reported on that case. The mean positive outcome for these colics was 63% (discharged from hospital), surgically treated horses had a 76% surviving rate compared to 42% in medically treated horses (those including all cases where surgery was not financially considered) Localized complication rates was less than previously described (none) and but acute uncontrolled hemorrhage was an unexpected complication not previously reported. Due to the bias of selection as the treated horses are the one being severely distended and the clinicians preference being on performing decompression, the usefulness of the procedure could not be demonstrated compared to undecompressed horses. Comparing two referrals centers results with opposite colic work‐up routines would be warranted. ABSTRACT E45 Comparison of blood gas analysis, electrolytes and plasma protein concentrations in horses at different altitudes Camilo Jaramillo 1; Maria Arias2; David Renaud1; Diego Gomez1 1University of Guelph; 2Universidad CES The objective of this study was to determine the venous blood gas values, electrolyte and plasma protein concentrations in adult horses residing at 5 different altitudes. One hundred and forty‐eight healthy Paso Fino horses >1.5 year‐old were enrolled. The horses lived at five different altitudes: 0 masl (n = 23), 1000 mamsl (3280 famsl, n = 25), 1500 mamsl (4921 famsl, n = 30), 2000 mamsl (6561 famsl n = 30) and 3000 mamsl (9842 famsl, n = 30). An EDAN i15® (Edan Instruments, Inc – Guangzhou – China, 2016), portable system was used to determine pH, PvCO2 (mm Hg) and HCO3‐ (mmol/L), hemoglobin (Hb, mg/dL), BE (mmol/L)] and whole blood electrolyte concentrations (mmol/L) (Na++, K+, Ca++, Cl‐ and L‐Lactate). Packed cell volume (PCV, %) was measured by blood centrifugation in a microhematocrit tube in a microhematocrit centrifuge. Total plasma protein was measured as total solids using a refractometer. A One‐way ANOVA with Tukey's HSD post hoc test or a Wilcoxon signed‐rank test, depending of the normality of the data, were conducted to compare groups. Horses at 0 mamsl had lower PCV (25 ± 2%) and Hb (8.3 ± 0.8 mg/dL) concentration than those horses living above 1000 mamsl (p < 0.05, for all comparisons). No differences in PCV and Hb were identified in horses living between 1000 and 3000 mamsl (p > 0.05, for all comparisons). The venous PvCO2 was significantly lower in horses residing at altitudes above 1000 mamsl (37.8 to 39 mm Hg) than those living at 0 mamsl (42 ± 4.8 mm Hg) (p = 0.001, for all comparisons). No differences in PvCO2 were identified in horses living between 1000 and 3000 mamsl. No differences in the concentration of whole blood electrolytes or plasma protein were observed in horses residing at any altitude. This study confirms the observation that red blood cell numbers increase with altitude. However, these differences were not identified when comparing horses living between 1000 to 3000 mamsl. Differences in PvCO2 also confirm hyperventilation as a respiratory adaptation to altitude. ABSTRACT E46 Imidocarb dipropionate fails to clear both Theileria equi and Theileria haneyi in superinfected horses Kelly Sears 1; Lindsay Fry2; Don Knowles1 1Washington State University; 2USDA‐ADRU Equine theileriosis continues to present challenges for the international movement of horses. A newly identified Theileria sp. of equids, Theileria haneyi, further complicates regulatory efforts as it is not detected by current diagnostic assays for Theileria equi. Mounting prevalence data supports the distribution of this species, along with T. equi, in multiple regions around the world, and recent publications have verified that superinfection with both species is possible. Prevention of equine theileriosis is largely reliant on chemosterilization with imidocarb dipropionate (ID). However, a previous report suggested that complete clearance is not achievable when a horse is infected with multiple species. The purpose of this study was to determine if the currently accepted ID treatment regimen (4 mg/kg q 72 h IM for 4 doses) would clear T. equi and T. haneyi in persistently, superinfected horses. Six experimentally infected horses were utilized. Three horses were infected with T. equi first, followed by T. haneyi, and three horses were infected with T. haneyi first, followed by T. equi. T. equi nested PCR was performed after each round of treatment, and suggested chemosterilization had not been achieved in a subset of horses. To verify the infection status following treatment, each horse was subsequently splenectomized. 2/3 of the horses first infected with T. haneyi developed severe T. equi recrudescence, requiring euthanasia, and verifying lack of successful treatment. In contrast, 3/3 of the horses first infected with T. equi failed to develop severe disease following splenectomy, confirming partial treatment success in this group. However, all horses remained persistently infected with T. haneyi. In conclusion, ID does not appear to be effective for complete chemosterilization of superinfected horses. ABSTRACT E47 Bile acids, GGT, and direct bilirubin as prognostic indicators for horses with liver disease Barbara Delvescovo 1; Joy Tomlinson1; Sally Anne DeNotta2 ; Elizabeth Hodge3; Lauren Bookbinder4; Hussni Mohammed1; Thomas Divers1 1Cornell University; 2University of Florida; 3University of Pennsylvania; 4College of Veterinary Medicine Michigan State University Bile Acids (BA) are markers of hepatic function. In equine practice they are commonly used to establish severity of liver disease and monitor response to treatment. Recent published data from Europe supports the use of BA as prognostic indicator of short and long‐term outcome in horses. Similar studies are not available in the United States. Etiopathology of hepatic diseases in horses from United States might differ from horses included in the European study causing predictive outcome value of BA to differ. Determining the prognostic value of BA in a population of horses with liver disease from Eastern United States might therefore provide a more accurate prognostic information for this marker in horses in this region. Our hypothesis was that moderately to severely increased BA values are not correlated with outcome in the population considered. The objective of the study was to retrospectively evaluate the predictive value of elevated BA on outcome in a population of horses presented to four referral hospitals in the Eastern United States. To test our hypothesis, we determined if BA values differed between survivors and non‐survivors. Moreover, GGT, and direct bilirubin (DB) were also evaluated in the studied population. Records of horses 1 or more years of age admitted to four referral centers between 1997 and 2018 with a BA measurement >30 μmol/L and at least 6 months follow up information were included in the study. Four of these horses were research horses. The highest single BA, GGT and DB value recorded for each horse was used for statistical analysis. BA, GGT, and direct bilirubin values were compared between survivors and non‐survivors. Eighty‐two horses met the inclusion criteria. These horses presented for liver disease. 55% of the horses survived at least 6 months post‐discharge. BA values were not significantly different between survivors and non‐survivors (p = 0.45). BA and GGT or Direct Bilirubin were not correlated. In the population evaluated GGT values were also not correlated with outcome (p = 0.15), instead direct bilirubin values were negatively correlated with outcome (p = 0.0). According to these results, BA values do not represent a reliable long‐term prognostic indicator across the different liver pathologies for this population of horses with liver dysfunction from Eastern United States. Instead DB values may be more reliable indicator of prognosis in a similar population of horses. ABSTRACT E48 Glucose attenuates ampk signaling in the absence of insulin in equine digital lamellae Erin F. Pinnell 1; James Belknap2; Teresa Burns2; Mauria Watts2; Paty Weber3 1The Ohio State University College of Veterinary Medicine; 2The Ohio State University; 3Michigan State University Equine insulin dysregulation (ID) is a known risk factor for the development of laminitis. 5′ adenosine monophosphate activated protein kinase (AMPK) is an important enzymatic regulator of energy homeostasis. AMPK signaling influences epithelial differentiation and adhesiveness, which are relevant to equine laminitis; therefore, AMPK is an important target to evaluate, particularly given that agonists are commercially available. The objective of this study was to determine the effects of insulin and glucose on AMPK activation (pAMPK) in keratinocytes and lamellar explants. Lamellar explants and keratinocytes from 2 different horses were collected and assigned to 3 incubation conditions: media control, media + glucose (0, 5, and 25 mg/dL), and media + glucose (0, 5, and 25 mg/dL) + insulin (10,000 mIU units/L). The concentration of pAMPK in treated cells and explants was determined using Western blot and compared between the groups. Glucose, in the absence of insulin at both the 5 and 25 mg/dL concentrations, decreased pAMPK concentration by ~80% compared to control conditions; the addition of insulin to the incubation did not appreciably change this response (pAMPK decreased by ~75% compared to the control). Glucose appears to attenuate AMPK signaling independently of insulin. In the digital lamellae of equids with ID, decreased concentrations of pAMPK could adversely influence differentiation and adhesiveness of keratinocytes in a way that contributes to lamellar failure following enhanced glucose delivery to the foot. AMPK agonists should be evaluated as potential therapeutic targets for equine ID and endocrinopathic laminitis. ABSTRACT E49 FluAvert stimulates immunity and reduces equine herpesvirus 1 replication in equine respiratory epithelial cells Gisela Soboll Hussey 1; Lila Zarski1; Wendy Vaala2; Craig Barnett2; Fairfield Bain2 1Michigan State University; 2Merck Animal Health Equine herpesvirus 1 (EHV‐1) is ubiquitous in horses worldwide and the cause of respiratory disease, late term abortion, and equine herpesvirus myeloencephalopathy (EHM). Currently, available vaccines are limited in their efficacy and prevention of viremia or EHM. This is likely related to the immunomodulatory properties of EHV‐1. Multiple EHV‐1 proteins have shown to interfere with induction of interferons, cytokines, chemokines, antigen presentation, and cellular immunity. We hypothesized that the mucosal influenza vaccine FluAvert, which is known to stimulate strong antiviral responses, will enhance antiviral innate immunity and that these responses would also provide protection from EHV‐1 infection. Primary equine respiratory epithelial cells (ERECs) were treated with FluAvert or Mock 1, 2, 5, or 7 days prior to inoculation with EHV‐1. Induction of interferons, cytokine and chemokine mRNA expression, and protein secretion was evaluated by high throughput qPCR and multiplex protein analysis. Further, intracellular and extracellular EHV‐1 titers were determined by qPCR. FluAvert treatment resulted in modulation of IL‐8, CCL2 and CXCL9 starting on day 5 post treatment. Coinciding with the timing of optimal chemokine/cytokine induction, EHV‐1 replication was most efficiently reduced in ERECs treated with FluAvert 5 days prior to EHV‐1 inoculation. In conclusion, our results suggest that FluAvert may be effective at counteracting some of the immune‐modulatory properties of EHV‐1 at the airway epithelium, and the peak for this response occurs 5–8 days post FluAvert treatment. Future in vivo studies are needed to investigate FluAvert as a prophylactic in situations where EHV‐1 exposure may occur. ABSTRACT E50 Effect of AMPK agonists on insulin and glucose dynamics in experimentally‐induced insulin dysregulation in horses Kathryn Timko; Laura Hostnik; Mauria Watts; Chiaming Chen; Adam Bercz; Ramiro Toribio; James Belknap; Teresa Burns The Ohio State University Insulin dysregulation (ID), a hallmark component of equine metabolic syndrome, is linked to the development of laminitis, a condition for which there are few pharmacologic treatment options. 5′‐Adenosine‐monophosphate‐activated protein kinase (AMPK) is a highly conserved heterotrimeric enzyme essential to cellular energy regulation and an important therapeutic target in humans with metabolic syndrome. The objective of this study was to assess the effects of AMPK agonist administration (metformin [MET], aspirin [ASP], and combination [MET/ASP]) on insulin and glucose dynamics in experimentally‐induced ID in light breed horses. Insulin dysregulation was induced in 14 adult light breed horses with dexamethasone (0.08 mg/kg PO q 24 h); horses were randomly assigned to groups and received either ASP (10 mg/kg PO q 24 h; n = 7) or MET (30 mg/kg PO q 12 h; n = 7) for 7 days. Seven horses then received MET/ASP for an additional 7 days. The oral sugar test (OST) and combined glucose and insulin test (CGIT) were used to assess ID at four time points: baseline, ID, ID + monotherapy, and ID + combination therapy. The OST area under the curve for glucose (AUCgluc0‐240) after combination treatment was significantly lower than at the ID and ID + monotherapy timepoints (p = 0.0052). The CGIT area under the curve for glucose (AUCgluc0‐150) was not significantly affected by AMPK agonist treatment (p = 0.0779). These findings suggest that MET/ASP combination therapy can synergistically improve insulin and glucose dynamics in horses and may have therapeutic value. ABSTRACT E51 Effect of AMPK agonists on hepatic AMPK‐Related gene expression in horses with experimentally‐induced insulin dysregulation Kathryn Timko; Laura Hostnik; Mauria Watts; Chiaming Chen; Adam Bercz; Ramiro Toribio; James Belknap; Teresa Burns The Ohio State University Insulin dysregulation (ID), a hallmark of equine metabolic syndrome (EMS), is intrinsically related to the development of laminitis. 5′‐Adenosine‐monophosphate‐activated protein kinase (AMPK) agonists are used in humans to promote euglycemia and enhance systemic insulin sensitivity, representing a promising therapy for horses with EMS. This study investigated hepatic AMPK signaling in response to AMPK agonists (metformin [MET], aspirin [ASP], combination [MET/ASP]) in horses with experimentally‐induced ID. Insulin dysregulation was induced in 14 adult light breed horses with dexamethasone (0.08 mg/kg PO q 24 h). The horses were assigned to groups, and each horse received either ASP (10 mg/kg PO q 24 h; n = 7) or MET (30 mg/kg PO q 12 h; n = 7) for 7 days. Seven horses then received MET/ASP for an additional 7 days. To assess AMPK regulation, liver biopsy samples were obtained at the following time points: baseline, ID, ID + monotherapy, and ID + combination therapy. Real‐time polymerase chain reaction (qPCR) was performed to evaluate expression of AMPKα, peroxisome proliferator‐activated receptor‐γ (PPARγ), peroxisome proliferator‐activated receptor‐ γ coactivator 1‐α (PGC1α), and phosphoenolpyruvate carboxykinase (PEPCK) at all timepoints. The expression of AMPKα was significantly increased with combination therapy compared to baseline (p = 0.0114). PPAR γ expression was significantly decreased at ID + monotherapy (p = 0.0026) but not with combination therapy, suggesting a partial response to combination treatment. The expression of PGC1α was not significantly affected by any treatment. PEPCK expression was significantly decreased by administration of dexamethasone (p = 0.0114). These findings suggest that AMPK agonist therapy can alter hepatic AMPK‐related gene expression in adult horses. ABSTRACT E52 Prevalence of Streptococcus equi in healthy horses in Colombia Camilo Jaramillo 1; Diego Gomez1; Brayan Fonseca2; Gabriela Mandiola1; Luis Arroyo1 1University of Guelph; 2Iowa State University Establishing the prevalence of Streptococcus equi in different locations is necessary since this information is underreported in the literature. The objective of this study was to determine the prevalence of S. equi in healthy horses in Colombia and the antimicrobial susceptibility of the recovered isolates. One hundred and thirty‐seven horses, older than six months of age, from 15 farms were enrolled. The sample size was estimated based on the horse population of the municipality sampled (3000 – government population census, 2017). The error rate was set at 5%, for an expected prevalence of 10% and a confidence interval of 95%. The sampling was carried out in a stratified manner such that it was proportional to the population size of each farm. The guttural pouch was swabbed via endoscopic guidance and culture was performed on the samples in 5% sheep blood agar. Gram positive cocci, β hemolytic and C Lancefield positive colonies were subcultured and DNA was extracted for PCR analysis. The primers SodA F (5′‐CAG CAT TCC TGC TGA CAT TCG TCA GG‐3′) and SodA R (5′‐CTG ACC AGC CTT ATT CAC AAC CAG CC‐3′) were used for Streptococcus equi bacterial identification. To confirm the genus and species of S. equi, the DNA PCR products were sequenced. An antibiotic disc diffusion test was performed with penicillin, ceftiofur, trimethoprim‐sulfamethoxazole (TMS), enrofloxacin and oxytetracycline. It was found that 15% (21/137) of the horses cultured positive, with all of the isolates reporting positive on PCR. Sequencing determined that S. equi ssp. equi accounted for 90% (19/21) of the isolates, while 10% were found to be S. equi ssp. zooepidemicus (2/21). In conclusion, this study confirms the presence of S. equi ssp. equi and S. equi ssp. zooepidemicus in healthy horses in Colombia. The calculated prevalence for individual animals was 15%. Lastly, all isolates were sensitive to TMS, penicillin, and ceftiofur and resistant to enrofloxacin and oxytetracycline. ABSTRACT E53 A prospective study of common laboratory variables in neonatal foals in Texas Laszlo Hunyadi 1; Emily Sundman2 1Texas Tech University; 2Equine Sports Medicine & Surgery This study was to evaluate inflammatory biomarkers in neonatal Quarter Horse foals with normal parturition, illness (including sepsis), and foals born to mares with complicated parturitions and placental abnormalities (abnormal mares). A prospective study was conducted with 64 foals at a private practice in northern Texas. Forty‐three normal foals, 7 ill/septic foals, and 14 clinically normal foals from abnormal mares were included in the study. Blood samples from foals were assessed for C‐reactive protein (CRP), haptoglobin, cortisol, adrenocorticotropic hormone (ACTH), and serum amyloid A (SAA) within 24 hours of birth. Statistically significant differences were found for haptoglobin, ACTH, and SAA. Evaluation of haptoglobin values demonstrated that 1 foal in the ill/septic category was above the normal range and all foals in the abnormal mare category were within the range for normal foals (30–107 mg/dL). Evaluation of ACTH values demonstrated that 2 ill/septic foals were above the normal range (5–91 pg/mL) and 1 foal in the abnormal mare category was below the range for normal foals. Evaluation of SAA values demonstrated that 5 ill/septic foals were above the range for normal foals (0–31 μg/mL), while all foals in the abnormal mare category were with the range for normal foals. The study showed a statistically significant difference in haptoglobin, ACTH, and SAA concentrations in neonatal foals; however, neither haptoglobin nor ACTH values showed clinically useful differences between the groups. SAA was clinically useful to identify ill/septic foals in comparison to normal foals. Evaluation of neonatal cortisol, ACTH, haptoglobin, or CRP did not provide clinically useful information to differentiate normal foals from sick foals. Birth to a mare with subsequent placental abnormalities did not result in clinically abnormal neonatal foals in this study. ABSTRACT E54 Comparison of different methods for measurement of electrolytes and detection of acid‐base disorders in horses Diego E. Gomez 1; Sebastien Buczinski2; Shannon Darby3; Megan Palmisano3; Rob Mackay3 1University of Guelph; 2University of Montreal; 3University of Florida The concentration of strong electrolytes (Na, K and Cl) can be determined using ion selective electrode technology based on direct or indirect potentiometric measuring. Significant differences in the measured concentrations of Na or Cl have been reported between analyzers, which can lead to disparities in the calculated values of the simplified strong ion difference (sSID) approach. The aims of this study were to determine the level of agreement between 2 analyzers for determining concentrations of strong electrolytes (Na and Cl) and the calculated variables of sSID approach, and to determine the level of agreement of both analyzers in identifying acid‐base disorders in sick horses. This study was conducted on 124 paired samples from sick horses. Samples for both analyzers were collected simultaneously by venipuncture of the jugular vein. Electrolytes were measured using a Beckman Coulter AU480 Chemistry analyser® (AA) and a Nova Biomedical Stat Profile® (BGA), respectively. The sSID variables were calculated as SID4 = (Na++K+)‐(Cl‐+L‐Lactate‐); A‐ = (0.22 x TP)/(1 + 10(6.65‐pH)) (g/dL) and USI = SID4 ‐ HCO3‐ – A‐. The acid‐base disorders were described when the following variables were outside of the following reference ranges: SID4 (38 to 47 mM/L), Atot (12 to 16 mM/L) and USI (−2 to 2 mM/L). The SID4 and USI concentrations were calculated with the values obtained from each analyzer. Agreement between the 2 analyzers was explored using Passing‐Bablok regression and Bland–Altman analysis. Intraclass correlation coefficient (ICC) was also used to determine the reliability between the SID and USI measurements from the two analyzers. Kappa coefficient test was used to evaluate the level of agreement between the two analyzers in detecting acid‐base disorders using prespecified cut‐offs. The results of Passing‐Bablok regression indicated significant methodologic differences in measuring Na and Cl, and the calculated values SID4 and USI (the Intercept (I) 95% CI did not include 0 and the slope (S) was different to 1 for all regressions). The Bland‐Altman plot indicated that the mean bias (95% limits of agreement) for Na, Cl, SID4 and USI between the 2 analyzers were: −1.2 mmol/L (−9.2 to 6.8), 4.4 mmol/L (−4.4 to 13), −5.4 mmol/L (−13 to 2) and −6.2 mmol/L (−14 to 1.7), respectively. The ICC of the measurement of the SID4 and USI for both analyzers was 0.55 (95%CI: −0.2 to 0.8) and 0.2 (95%CI: −0.15 to 0.48), respectively. Kappa coefficient analysis showed no agreement between BGA and AA for detection of SID4 (K = 0.20, 95%CI, 0.1 to 0.31) or USI abnormalities (K = −0.04, 95%CI, −0.11 to 0.02). Comparison between both analyzers showed methodologic differences in measuring Na and Cl, and calculated SID4 and USI, which resulted in a poor agreement between the analyzers to diagnose acid‐base disorders in sick horses. ABSTRACT E55 Urinary L‐lactate measures in adult horses Ilana Glasberg; Scott Austin; Pamela Wilkins University of Illinois College of Veterinary Medicine Urinary L‐lactate (ULAC) and ULAC:creatinine ratios are altered in human renal disease and neonatal Hypoxic‐Ischemic Encephalopathy, but have not been assessed in the horse. Urine (U) and blood sodium (Na), LAC and creatinine concentrations were measured in 6 healthy adult horses. Na and creatinine were measured by the clinical laboratory. LAC was measured using 2 point‐of‐care (POC) devices, Lactate Scout and Lactate Plus. LAC measurements were performed in triplicate with the mean used in analysis. USG was measured by refractometer and dipstick. ULAC:creatinine, UNa:creatinine and fractional excretions (Fx) of LAC and Na were calculated. Data are reported as mean ± SD, associations examined by linear regression. Results are from the Lactate Scout as the Lactate Plus did not report values for urine. Respectively, blood LAC and Na were 0.9 ± 0.3 mmol/L and 134.7 ± 2.9 mEq/L, ULAC and UNa 5.1 ± 1.0 mmol/L and 20 ± 9 mEq/L, UCreatinine and creatinine 178.4 ± 89.4 and 1.00 ± 0.14. ULAC:creatinine and UNa:creatinine were 0.27 ± 0.03 mmol/L and 0.24 ± 0.32 respectively while FxLAC and FxNa were 3.03 ± 1.06 and 0.07 ± 0.03. Refractometer USG was 1.041 ± 0.01, dipstick USG was always >1.005. Blood LAC and Na were positively associated (R2 = 62.5%, p < 0.001), as were ULAC and UNa, (R2 = 59.9%, p < 0.001). ULAC:creatinine and UNa:creatinine were more strongly associated (R2 = 81.7%, p < 0.001) as were FxNa and FxLAC (R2 = 84.4%, p < 0.001). Urinary LAC measurements obtained using the Lactate Scout POC are reported here for the first time in the horse. LAC and Na appear related with that relationship being stronger in urine than in blood, suggesting that both undergo modification by the kidney. ABSTRACT E56 Evaluation of three different doses of thyrotropin releasing hormone in miniature horses Alfredo Sanchez‐Londono 1 ; Nicholas Frank2; Steve Grubbs3; Pilar Hermida2; Erik Hofmeister1 1Auburn University; 2Cummings School of Veterinary Medicine at Tufts University; 3Boehringer‐Ingelheim The purpose of the study was to evaluate adrenocorticotropin hormone (ACTH) responses following the administration of three different doses (1.0 mg, 0.5 mg and 0.25 mg) of thyrotropin releasing hormone (TRH) to Miniature horses with and without pituitary pars intermedia dysfunction (PPID). A total of 20 client‐owned Miniature horses were enrolled in the study. Group 1 (non‐PPID control horses) consisted of 10 horses less than 10 years of age with no evidence of clinical signs of PPID and/or a normal basal ACTH concentration. Group 2 consisted of 10 horses over 15 years of age with clinical evidence of PPID and/or an increased (>35 pg/ml) basal ACTH concentration. A complete physical examination, basal blood draw for measuring ACTH concentrations and a questionnaire regarding health issues were completed on the first visit. On days 0, 14 and 28, both groups of horses underwent TRH stimulation tests using three different doses of TRH given intravenously on different calendar days at least two weeks apart. Testing was performed between the months of February and June. Three doses of TRH were evaluated: 1.0 mg, 0.5 mg, and 0.25 mg. On the day of testing, approximately 5 ml of blood was drawn into each EDTA tube via jugular venipuncture and blood was collected before and 2, 5, 10 and 20 minutes after TRH administration. Blood and anticoagulant were mixed gently by inverting tubes several times and then the tubes were chilled immediately in either an ice bath or a refrigerator. Tubes were centrifuged within 4 hours of collection and plasma was separated and transferred to cryovials for storage at −20°C. Frozen plasma was shipped with ice packs via overnight courier service. Plasma ACTH concentrations were measured using a solid‐phase, two site sequential, chemiluminescent immunoassay designed for Immulite at Cornell University Animal Health Diagnostic Center. Receiver operator characteristic (ROC) curves were plotted for each time point with each TRH dose and Younden's value was calculated and used to determine the best cutoff point for diagnosis. Analyses were performed using a commercially available statistical software package (GraphPad Prism v.8) and p < 0.05 was considered significant. The ROC analysis results were examined to determine diagnostic performance, the 1.0 mg TRH dose and 10 minute time point had 100% sensitivity and 90% specificity with a cutoff value of 130 pg/ml, compared to the 0.5 mg TRH dose at 10 minutes which had a 100% sensitivity and 80% specificity with a cutoff value of 121 pg/ml. In contrast, the 0.25 mg TRH dosage had 90% sensitivity and 80% specificity with a cutoff value of 104.3 pg/ml at 20 minutes post TRH injection. All other combinations had lower sensitivity and specificity values. Thyrotropin releasing hormone (TRH) dosages of 0.5 mg and 1.0 mg have the best sensitivity and specificity at 10 minutes post injections for consistent identification and diagnosis of miniature horses with PPID. A larger group of horses should be examined in the future to determine whether a lower TRH dose can be used as a diagnostic test in miniature horses. ABSTRACT E57 Prerenal and renal failure in horses: Retrospective study in an equine hospital (1987–2019) Daniel Jean 1; Guillaume Bon2; Romane Warlop3 1University of Montreal; 2Cliniques de Conques; 3Private Practice Renal failure in horses is described in the literature but few objective information is available on the survival rate and the prognostic factors in a large number of equine patients. The purpose of this clinical study was to identify equine patients with renal failure, determine the survival rate as well as the prognostic factors, and establish correlation between clinical data and necropsy findings. The retrospective study was performed with medical files of horses presented with hypercreatinemia (>150 μmol/l) combined with at least one urology examination during hospitalization between 1987 and 2019 at the Veterinary Teaching Hospital at the University of Montreal. Equine patients were divided into three groups: (1) hypercreatinemia with a normal urology, (2) acute renal failure, and (3) chronic renal failure considering the clinical context. Two hundred sixty‐three horses met the criteria. One hundred thirty‐eight horses were in acute renal failure, 94 in prerenal failure and 31 in chronic renal failure. The short‐term survival rate was 75.5% (prerenal failure), 60% (renal failure) and 55% (chronic renal failure) respectively. The survival rate for the three groups increased throughout period and was correlated to the lowest average creatinine value observed in these patients in the last decade compared to the period between 1987 to 2006. The mortality rate was directly correlated to the highest creatinine value of equine patients during hospitalization. In conclusion, the survival rate of renal failure improved during this three decades period and could be explained by the improvement of therapeutic management throughout period. ABSTRACT E58 The thyrotropin‐releasing hormone procedure produces repeatable ACTH concentrations in PPID‐negative and PPID‐positive horses Rhonda M. Hoffman 1; John Haffner1; Steve Grubbs2 1Middle Tennessee State University; 2Boehringer Ingelheim Pituitary Pars Intermedia Dysfunction (PPID) affects approximately 20% of horses aged 15 and older. Advanced cases of PPID in horses exhibiting generalized hypertrichosis are easily identified, but diagnosing horses with subtle clinical signs of early PPID without generalized hypertrichosis is more challenging. Basal ACTH has a lower diagnostic sensitivity in horses with early compared to advanced PPID. Compared to basal ACTH, the thyrotropin‐releasing hormone (TRH) stimulation procedure has been shown to have a greater sensitivity of detecting horses with subtle signs of PPID, but it is unknown if the ACTH response to TRH is repeatable in individual horses. The purpose of this study was to conduct TRH stimulation tests at 4‐week intervals, beginning in February and ending in June, in horses with and without PPID to determine the repeatability of ACTH response after TRH stimulation. Twelve horses (PPID+ and PPID–) with a mean age of 18.8 yrs (range 12 to 25 yrs) were used. Basal ACTH concentration from blood collected on Day −45 was used to identify PPID status of each horse. On Day 0, all horses had blood collected for basal ACTH followed by IV administration of 1 mg TRH. Blood was then collected exactly 10 min post‐TRH administration (T10‐ACTH). Blood samples were centrifuged and plasma was frozen at ‐80C until ACTH analysis using a chemiluminescent immunoassay (Immulite) at the Animal Health Diagnostic Laboratory, Cornell University, Ithaca, NY. The TRH stimulation procedure was repeated on Days 28, 56, 84 and 112. These subsequent samples were compared to the T10‐ACTH samples collected on Day 0. Data were analyzed using a mixed model with repeated measures to compare T10‐ACTH and the percent increase of ACTH after TRH stimulation, using horse as the subject and Day as the repeated effect. Pearson's correlation coefficients were used to examine relationships between T10‐ACTH on Days 28, 56, 84 and 112 to the T10‐ACTH on Day 0. Bland‐Altman plots were constructed to compare T10‐ACTH on Days 28, 56, 84 and 112 to the T10‐ACTH on Day 0. Of the 12 horses, the TRH stimulation indicated 5 negative and 5 positive for PPID, with 2 horses equivocal. The average ACTH in PPID‐ horses was 17.6 ± 0.7 pg/mL (basal) and 61.4 ± 9.2 pg/mL (T10‐ACTH), with a 349 ± 41% increase in ACTH after TRH stimulation. The average ACTH in PPID+ horses was 43.5 ± 3.6 pg/mL (basal) and 410 ± 58 pg/mL (T10‐ACTH), with a 948 ± 194% increase in ACTH after TRH stimulation. Repeated measures analysis indicated no effect of Day on T10‐ACTH (p = 0.40) or the percent increase of ACTH after TRH stimulation (p = 0.12). Pearson's correlation coefficients indicated strong relationships between T10‐ACTH on Day 0 and all other days (R > 0.70, p < 0.01). Bland‐Altman plots indicated an average Day bias of 27 pg/mL in all horses compared to Day 0, with a Day bias of 10 pg/mL in PPID– and 43 pg/mL in PPID+ horses. The Immulite inter‐assay CV was 9.3%, which accounts for most of the observed Day bias. In conclusion, the TRH stimulation procedure produces repeatable ACTH concentrations in samples collected 10 min after administration of TRH in horses collected at 4‐week intervals over 112 days beginning in February through June. ACKNOWLEDGMENTS The authors would like to acknowledge Boehringer Ingelheim Animal Health and the Middle Tennessee State University Horse Science program for supporting this work. ABSTRACT E59 Methodologic comparison of two analyzers for measurement of glucose and creatinine concentrations in sick Horses Diego E. Gomez 1; Sebastien Buczinski2; Megan Palmisano3; Shannon Darby3; Rob Mackay3 1University of Guelph; 2University of Montreal; 3University of Florida Accurate and efficient assessment of blood glucose concentration is critical in the clinical management of many pathological conditions in equine medicine. Plasma creatinine concentration is the most widely used and commonly accepted criterion in the medical laboratory for the evaluation of renal function. Methodological interferences may significantly affect the results of these two analytes and might influence therapeutic decisions. The aim of this study was to determine the level of agreement between 2 different analyzers for determining concentrations of glucose and creatinine in sick adult horses. Blood samples from 124 sick horses were used in this study. Samples for both analyzers were collected simultaneously by venipuncture of the jugular vein. Glucose and creatinine were measured using a Beckman Coulter AU480 Chemistry analyser® (BCCA) and a Nova Biomedical Stat Profile® (NBSP), respectively. Passing‐Bablok regression and Bland‐Altman analysis were performed to determine the level of agreement between the 2 analyzers. The level of agreement between the two analyzers in detecting hyperglycemia (glucose >120 mg/dL) and hypercreatininemia (creatinine >2 mg/dL) was explored using the Kappa coefficient test using prespecified cut‐offs. McNemar's test was used to evaluate whether the measurement of glucose and creatinine with different analyzers are equally likely to identify an hyperglycemia and hypercreatininemia. On admission, NBSP detected 64/119 (54%) horses with hyperglycemia whereas BCCA identified 73/119 (62%). NBSP detected 28/122 (23%) with hypercreatininemia while BCCA identified 36/122 (30%). The results of Passing‐Bablok regression failed to identify significant methodologic differences between analyzers for measuring glucose and creatinine (the Intercept (I) 95% CI include 0 and the slope (S) was equal to 1 for both regressions). The Bland‐Altman plot indicated that the mean bias (95% limits of agreement) for glucose was −4.7 mg/dL (−70 to 60 mmol/L) and for creatinine was 0 mg/dL (−3 to 3). Kappa coefficient analysis showed a fair agreement between analyzers for detection of hyperglycemia (K = 0.43, 95%CI, 0.27 to 0.59) and hypercreatininemia (K = 0.58, 95%CI, 0.41 to 0.74) in sick horses. McNemar's test showed that both analyzers were equally likely to detect hyperglycemia (p = 0.11) and hypercreatininemia (p = 0.07) in sick horses. Methodologic differences in measuring glucose and creatinine by two different analyzers were not detected in this study. ABSTRACT E60 Investigation of neurological and nephrogenic side effects of polymyxin B administration in healthy horses Julia N. van Spijk 1; Katrin Beckmann2; Meret Wehrli Eser1; Martina Boxler3; Martina Stirn4; Thea Rhyner5; Lanja Saleh6; Angelika Schoster1 1Clinic for Equine Internal Medicine, Vetsuisse Faculty, University of Zurich; 2Section of Neurology, Department of Small Animals, Vetsuisse Faculty, University of Zurich; 3Institute of Forensic Medicine, University of Zurich; 4Clinical Laboratory, Department of Clinical Services, Vetsuisse Faculty, University of Zurich; 5Equine National Center; Dana Kaelin – Clinic for Equine Internal Medicine, Vetsuisse Faculty, University of Zurich; 6Institute of Clinical Chemistry, University Hospital Zurich Polymyxin B (PolyB) is used in horses due to its antiendotoxic effect. Neurologic and nephrogenic side effects limit its use in human medicine. The objective of this study was to investigate side effects of PolyB in healthy horses. In a prospective, randomized, blinded cross over trial six healthy horses received treatment A (PolyB 6000 IU/kg IV q 12 h for 84 h) followed by treatment B (PolyB as before + gentamicin 10 mg/kg IV q 24 h for 84 h) or treatment B followed by treatment A with a wash out period of 3 weeks. Ataxia was scored by three blinded observers on video recordings obtained daily before, during, and three days after treatment. Serum concentration of PolyB [PolyB] and gentamicin [gentamicin] were measured daily, serum creatinine and urine analysis every other day. An ordinal mixed multivariable model was used to evaluate the effect of treatment group, number of PolyB dose, time since last dose, and [PolyB] and [gentamicin] on ataxia score. All horses developed proprioceptive ataxia (median: 1–3/5) in both treatment groups. A statistically significant effect of an increasing number of PolyB doses (p < 0.001) and treatment group (p < 0.01) was seen. Median ataxia score increased from 0 to 2/5 (treatment A) and from 0.5 to 3/5 (treatment B). Three days after treatment, median ataxia score decreased to 0/5 and 1/5 in treatment group A and B, respectively, with a statistically significant effect of time since last dose (p < 0.001). [PolyB] and [gentamicin] had no effect on ataxia score. Weighted kappa of intra‐rater agreement of ataxia was 0.5, 0.7, and 0.9. Inter‐rater agreement was 0.3–0.6. Clinical, laboratory, and the remaining parts of neurological exam were within normal limits during the study period. PolyB administration led to transient ataxia in healthy horses. Severity was dependent on duration of therapy and concurrent treatment with gentamicin. No nephrotoxic side effects were observed. ABSTRACT E61 Physiological changes associated with estrous cycle on adrenocorticotropic hormone and insulin concentration in mares François‐René Bertin; Gemma Hicks; Natalie Fraser The University of Queensland Pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID) are both associated with poor reproduction performance and failure to conceive can trigger endocrine testing. The physiological changes associated with a normal estrous cycle on adrenocorticotropic hormone (ACTH) and insulin are poorly described, and test interpretation can be difficult. We hypothesized that estrous cycle would alter ACTH and insulin concentrations. Eighteen mares with ages ranging from 3 to 18 years and body condition scores ranging from 4 to 6/9 with no clinical signs suggestive of or laboratory findings consistent with PPID and ID were followed during their reproduction season. ACTH and insulin concentrations were measured at the periovulatory period, the postovulatory period as well as 14 and 28 days after ovulation. Determination of the stage in the estrous cycle was determined by ultrasound and progesterone concentrations. All the mares were inseminated at ovulation and gestation was then confirmed by ultrasound. Mares were grouped by age (younger or older than 12 years of age) and by gestation status (pregnant or not). Eleven mares became pregnant and age was not associated with pregnancy. There was a significant effect of estrous cycle stage and gestation on ACTH concentrations with higher ACTH concentrations at 14 days after ovulation (p = .0023) and in pregnant mares (p = .0097). No significant effect of estrous cycle stage or gestation on insulin concentrations was detected. ACTH concentrations change with estrous cycle and pregnancy. Therefore, knowledge of a mare's reproductive status might be beneficial when interpreting an ACTH concentration. ABSTRACT E62 Omega‐3 fatty acid incorporation into phosphatidylcholine in plasma, synovial fluid, and surfactant from supplemented horses Undine Christmann; Courtney Hancock; Audrey Emery; Jesse Poovey; Casey Hagg; Stacy Anderson; Seth Chapman; Eric Mattson; Paul Wood College of Veterinary Medicine, Lincoln Memorial University Omega‐3 fatty acids are known for their ability to modulate inflammation. Horses with asthma or osteoarthritis frequently receive these supplements in conjunction with other treatments. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are integrated into lipids which can be used to measure their uptake into different body compartments. The purpose of this study was to evaluate DHA and EPA incorporation into phosphatidylcholine in plasma, synovial fluid, and surfactant from horses. Twenty healthy horses were included in this study and randomly assigned to the supplement or control group. Supplemented horses received 8.3 g EPA and 5.3 g DHA orally 1x/day for 90 days. Horses were evaluated on days 0 (baseline), 30, 60, and 90. Samples included blood, synovial fluid, and bronchoalveolar lavage fluid. Sample lipidomic profiles were determined using high‐resolution mass spectrometry. Data were analyzed with a mixed‐effects repeated measures ANOVA (Tukey‐Kramer posthoc test; values of p < 0.05 considered as significant). Significantly higher relative levels of DHA and EPA containing phosphatidylcholine species (PC 40:6 and PC 40:5) were noted in plasma, synovial fluid, and surfactant from supplemented horses compared to control horses and in supplemented horses on days 30, 60, and 90 of collection versus baseline. Levels of PC 40:6 and PC 40:5 were stable within the group of control horses with no significant differences between sampling times. In conclusion, incorporation of DHA and EPA into phosphatidylcholine reliably reflects their uptake in different body compartments. The biological effects and clinical relevance of these findings remain to be determined. ABSTRACT E63 Insulin dysregulation variables in equine metabolic syndrome are similar in horses with previous non‐endocrinopathic founder Rhonda M. Hoffman; John Haffner Middle Tennessee State University The objective of this study was to compare measures of insulin dysregulation using a Frequently Sampled Intravenous Glucose Tolerance test (FSIGT) in two types of foundered horses: those with Equine Metabolic Syndrome (EMS) versus horses that had a single bout of founder caused by non‐endocrinopathic stress or injury, with both founder types compared to normal, never foundered, controls. The hypothesis was that measures of insulin dysregulation would be greater in horses with EMS compared to control horses and those with a previous non‐endocrinopathic founder. Eighteen horses, averaging 503 ± 53 kg BW, 6.5 ± 0.9 BCS, and aged 12 ± 5 yrs were used. Of these, 6 horses had chronic, repeated laminitis and founder associated with EMS; 6 previously had a single bout of founder not related to EMS, named Other Non‐Endocrinopathic Founder (ONEF, including concussion, overheating, injury, or acute illness), and 6 were normal controls (CON), having no history of laminitis. All horses tested negative for Pituitary Pars Intermedia Dysfunction. Lateral radiographs of front feet indicated coffin bone rotation in all foundered horses and normal anatomy in CON horses. None exhibited acute phase laminitis, with the last incidence reported at 12 ± 5 mos for EMS and 60 ± 24 mos for ONEF horses (p < 0.0001). Age, BW, and BCS were not different between groups (p = 0.12). Prior to testing, horses were housed overnight in stalls and provided low‐NSC mature grass hay and water. Jugular catheters were placed, and basal samples collected. For the FSIGT, 300 mg glucose/kg BW was infused IV, and 30 mU insulin/kg BW administered 20 min later. During the FSIGT, 31 venous samples were collected, at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 19, 22, 23, 24, 25, 27, 30, 35, 40, 50, 60, 70, 80, 90, 100, 120, 150, 180 and 240 min after the initial glucose dose. The 240 min sample was included due to expected insulin dysregulation and slower glucose clearance in the EMS horses. Blood samples were collected into heparinized sample tubes and placed in ice water until plasma was removed 10 to 20 min later, then frozen at −4°C. A colorimetric assay was used to measure glucose, and RIA for insulin. The FSIGT partitions glucose disposal into insulin‐independent glucose clearance, or glucose effectiveness (Sg), and insulin‐dependent glucose disposal, or insulin sensitivity (Si). Both Sg and Si are described in minimal model analysis by two differential equations solved simultaneously using relative changes in blood glucose and insulin as influenced by the FSIGT. The minimal model estimates acute insulin response to glucose (AIRg) using the area under the curve for the first 20 min of the FSIGT, which represents pancreatic β‐cell responsiveness. The disposition index (DI) is the multiplied product of Si x AIRg and accounts for the appropriateness of the AIRg relative to Si. The Si, Sg, AIRg and DI were calculated from the FSIGT data using MinMod Millennium and WinSAAM software. Data were tested for normality and analyzed using a mixed model with repeated measures using horse as the subject and sample time as the repeated effect, to compare the effects of group (EMS, ONEF, CON) on basal glucose and insulin, Si, Sg, AIRg and DI. Table 1 summarizes means ± SE of horse clinical characteristics and variables related to insulin dysregulation. Basal insulin was higher in EMS than ONEF (p = 0.033) and CON horses (p = 0.013), but CON and ONEF were not different (p = 0.41). Insulin sensitivity was lower in EMS than CON horses (p = 0.015), but ONEF were not different from either CON (p = 0.19) or EMS (p = 0.46). The AIRg was greater in EMS than CON horses (p = 0.034), but ONEF was not different from either CON (p = 0.23) or EMS (p = 0.37). There was no difference between groups in basal glucose (p = 0.43), Sg (p = 0.13) or DI (p = 0.37). The lower Si and higher AIRg in EMS vs CON horses indicated expected insulin dysregulation similar to previous reports. The lack of difference in Sg of EMS and CON separates these EMS horses from previous reports of obese horses, which exhibit higher insulin‐independent glucose clearance. Body condition scores of the EMS horses were not different from ONEF or CON, so perhaps obesity, but not EMS per se, affects peripheral tissue glucose transporters that act independent of insulin. Basal insulin was greater in EMS vs ONEF but similar in ONEF and CON, which suggests a difference between effects of founder type. Basal insulin in ONEF horses did not meet the cutoff for identification as laminitis‐prone (defined as >20 mIU/L, ECEIM Consensus Statement, 2019). Insulin sensitivity in ONEF was not different from either EMS or CON, and was in between the cutoff criteria in horses previously defined as insulin dysregulated (<1.0 L x mIU‐1 x min‐1 x 10‐4) or insulin sensitive (>1.5 L x mIU‐1 x min‐1 x 10‐4). These results, combined with the lack of difference in AIRg between ONEF and EMS, suggest that ONEF horses may be insulin dysregulated at a degree below clinical detection. The endocrine status of the ONEF horses at the time of their single bout of founder is unknown. Thus, it is also unknown whether a sub‐clinical insulin dysregulation existed that increased the risk of a single‐bout of founder in the ONEF horses, or if the one‐time non‐endocrinopathic founder produced endocrine changes that resulted in persistent sub‐clinical insulin dysregulation. ACKNOWLEDGMENT: The American Quarter Horse Foundation's support of this work is gratefully acknowledged.   ABSTRACT E64 Outcome and survival in 9 horses diagnosed with hematopoietic neoplasia and treated with cytotoxic chemotherapy Hannah Manning; Erin Pinnell; Adam Bercz; Teresa Burns The Ohio State University Hematopoietic neoplasia in the horse is rare; once diagnosed, it can be treated with various cytotoxic agents. Horses appear relatively tolerant of the adverse effects of cytotoxic chemotherapeutics; however, little information exists in the literature regarding the use and safety of these drugs in equine practice. The administration of systemic chemotherapy in horses diagnosed with hematopoietic malignancies is also limited based on negative perceptions regarding treatment efficacy and cost. The objective of this study was to evaluate outcomes, survival, adverse events, and client satisfaction in horses diagnosed with hematopoietic neoplasia and treated with systemic chemotherapeutics. Medical records of horses diagnosed with hematopoietic neoplasia and treated with systemic chemotherapeutics from 2005–2019 were evaluated. Nine horses were selected for inclusion. Diagnoses included lymphoma in 77.8% (7/9) and leukemia in 22.2% (2/9) of patients. Survival time ranged from 8–556 days, with 66.7% (6/9) of patients surviving 0–11 months and 33.3% (3/9) of patients surviving 12+ months post diagnosis and treatment with systemic chemotherapy. Of the patients in our study population, 66.7% (6/9) had no adverse effects reported within the medical record. Side effects reported included self‐limiting tachycardia, tachypnea, pyrexia, alopecia, and abortion. Of the clients that responded to surveys, their satisfaction with treatment was high, with none of them noting side effects in their horses and a majority reporting they would treat another horse with chemotherapy. Treatment of hematopoietic malignancies with cytotoxic chemotherapeutics appears to be safe, reasonable, and well tolerated in horses, and investigation to optimize therapeutic protocols is warranted. ABSTRACT E65 Glucose stimulates GLP‐2 secretion from equine small intestine Melody A. de Laat; Poppy Sibthorpe; Robert Spence Queensland University of Technology Glucagon‐like peptide‐2 (GLP‐2) is secreted by enteroendocrine cells in the small intestine in response to dietary nutrients and increases epithelial cell density and glucose transporter (SGLT‐1) expression, which increases glucose uptake. Equine insulin dysregulation is associated with increased glucose bioavailability and plasma GLP‐2 concentrations are higher in insulin‐dysregulated, compared to metabolically healthy, ponies. This study aimed to determine in vitro whether intestinal GLP‐2 secretion increases in response to glucose and whether inhibition of SGLT‐1 would reduce GLP‐2 concentration. Equine jejunum (n = 6; in triplicate) was collected from an abattoir, rinsed with ice‐cold saline and placed in transport buffer prior to removal of serosa and sectioning (~100 mg explants). Tissues were incubated for 60 min at 37°C with 0 or 12 mM added glucose to determine glucose‐dependent GLP‐2 secretion. Subsequently, fresh explants were incubated with or without two inhibitors (separately), phlorizin (1 mM; SGLT‐1 inhibitor) and phloretin (0.67 mM; SGLT‐1 and GLUT‐2 inhibitor), for 60 min with 12 mM glucose. An ELISA was used to measure GLP‐2 secretion which was normalized to protein concentration. Stimulation with 12 mM glucose increased (p = 0.03) GLP‐2 secretion. This glucose‐dependent GLP‐2 secretion was inhibited by both phlorizin (p = 0.02) and phloretin (p = 0.03). This experiment confirmed that equine jejunum secretes GLP‐2 which increases in response to glucose stimulation and can be reduced with SGLT‐1 inhibitors. These data contribute to understanding of mechanisms potentially associated with increased glucose bioavailability in insulin‐dysregulated horses and provide preliminary information for future investigations of the pathophysiology of insulin dysregulation. ABSTRACT E66 Blood vitamin C, vitamin B and cortisol concentrations in healthy and critically ill foals Katarzyna Dembek 1; David Wong2; Lauren Young1 1Iowa State University; 2VA‐MD College of Veterinary Medicine Sepsis is a common disease in neonatal foals with a variety of therapeutics being used to facilitate recovery. Some evidence suggests that administration of hydrocortisone, vitamin C and vitamin B may improve outcome in people with sepsis, but information is not available in regard to these variables in healthy or ill neonatal foals. The goal of this study was to document and compare the concentrations of vitamin C, vitamin B and cortisol in healthy and critically ill neonatal foals. We hypothesized that vitamin C and B concentrations will be lower in septic foals compared to healthy controls and that hypovitaminosis C and B will be associated with severity of disease and outcome in critically ill foals. Blood samples were collected from healthy (n = 15), septic (positive blood culture and/or sepsis score > 12 [n = 17]) and sick non‐septic (SNS; n = 15) foals <1 week of age at the time of admission and 72 and 120 hours after admission. Vitamin C and B concentrations were measured with high performance liquid chromatography mass spectrometry and cortisol concentration was determined by immunoassay. Hypovitaminosis C and B was defined based on the lower level of 95% confidence interval for vitamins concentrations in healthy foals. The prevalence of hypovitaminosis C on admission (defined as vitamin C < 7 μg/dL) was 58% and 26% in septic and SNS foals, respectively. Hypovitaminosis B (vitamin B < 2 ng/mL) was more frequent in septic foals (47%) compared to SNS (13%), (p < 0.05). In septic foals, vitamin B and C concentrations were lower than in healthy foals at 72 and 120 hours after admission (p < 0.05). Cortisol concentration was higher in septic and SNS foals compared to healthy foals on admission (p < 0.05). Low vitamin C and B concentrations were associated with severity of disease in neonatal foals. Vitamin C and B hypovitaminosis may contribute to a pro‐inflammatory state in equine neonatal sepsis. ABSTRACT E67 The prevalence of cyathostomin anthelmintic resistance on horse farms in Prince Edward Island, Canada Jaimie Amanda Butler 1; Haley Greenbank1; Rebecca Parrish1; Martin Nielsen2; William Stoughton1 1Atlantic Veterinary College; 2Gluck Equine Research Center, University of Kentucky The majority of adult equines carry a parasite burden consisting mainly of nematodes, which include 40 different species of small strongyles (cyathostomins) and to a lesser extent large strongyles. There are currently three classes of anthelmintics to treat strongyle infections. These anthelmintics were initially efficacious in controlling cyathostomins; however, due to the widespread overuse of anthelmintics, cyathostomins have developed increasing resistance to the classes benzimidazoles and pyrimidines, with macrocyclic lactones displaying early signs of resistance. Detection of early resistance can be investigated using egg reappearance periods (ERP). The ERP is defined as the week cyathostomin egg shedding occurs after an effective anthelmintic treatment. Shortening of this period overtime is an indicator of anthelmintic resistance. The objective of this study was to investigate the prevalence of cyathostomin anthelmintic resistance to pyrantel pamoate and ivermectin, and to determine egg reappearance periods on horse farms in Prince Edward Island (PEI), Canada. One hundred and one horses on 15 horse farms across PEI, Canada were enrolled in the study. The number of horses per farm ranged from 4–11 with means of 6.9 and 6.2 for pyrantel pamoate and ivermectin groups, respectively. Fecal egg counts (FEC) were performed initially on 270 horses. Horses shedding >200 eggs per gram (epg) were treated with 6.6 mg/kg PO of pyrantel pamoate (n = 101). Fecal egg counts were conducted every 2 weeks for 8 weeks post treatment. Once FEC were above 200 epg horses were dewormed with 0.2 mg/kg PO of ivermectin (n = 87), and FEC were performed every 2–3 weeks for 7 weeks. Fecal egg count reduction tests (FECRT) and egg reappearance periods were used to detect the efficacy of each anthelmintic. Fecal egg count reduction tests detected pyrantel pamoate resistance on 2/14 farms. No resistance to ivermectin was detected using the FECRT. Egg reappearance periods detected no early resistance to pyrantel pamoate on susceptible farms, while ivermectin had a reduction in the ERP of 5 weeks on 2/12 farms. The prevalence of pyrantel pamoate cyathostomin resistance was less on PEI than other studies, while the shortened ERP of 5 weeks for ivermectin was comparable to findings of early resistance in other parts of the world. These findings will allow us to educate owners and veterinarians on appropriate anthelmintic protocols in PEI, and can be used as a baseline for continued monitoring of ERP and anthelmintic resistance in this region. ABSTRACT E68 Evaluation of a clinical sign scoring system for pituitary pars intermedia dysfunction in horses Steven Grubbs 1; Dwana Neal1; Tom Keefe2 1Boehringer Ingelheim; 2Colorado State University Pituitary pars intermedia dysfunction (PPID) has been described as the most common endocrinologic disorder of aged horses. The diagnosis consists of information obtained from current history, a physical examination to document clinical signs associated with PPID, and then to confirm these findings, diagnostically evaluate adrenocorticotropic hormone (ACTH). In many horses with reported PPID associated signs, results of ACTH evaluation were within normal reference range. It is possible that veterinarians were testing horses without clinical signs or with very subtle PPID‐associated signs. In addition, certain PPID‐associated signs, by themselves, may not be predictive of disease. Based on this dilemma, the purpose of this study was to obtain epidemiological information from a large population of horses, and then develop a clinical sign score (CSS) based on odds ratios. In all, 2,989 horses exhibiting one or more of the typical signs of PPID were enrolled in the study. At initial visit, a physical examination was conducted and blood drawn for basal adrenocorticotropic hormone (ACTH), insulin, and glucose. All samples were centrifuged, plasma shipped overnight and analyzed for ACTH, insulin, and glucose by the Animal Health Diagnostic Center, Cornell University, Ithaca, NY. The association between PPID status, based on ACTH results, and each of the demographic variables and test results for insulin and glucose were statistically evaluated individually using the Pearson chi‐square test and collectively using multiple logistic regression analysis of PPID to provide odds ratios for PPID associated with the clinical signs. The CSS is the product of the odds ratios for PPID vs. all clinical signs collectively. Based on statistical analyses of the CSS data, a value of 1.5 for the CSS was selected as a cut‐off for predicting PPID status. The higher the CSS the more likely a horse was PPID+. Clinical sign scores ranged from 0.60 to 5.51, with an overall geometric mean of 1.59. Using this model in the non‐fall months, the CSS score with an ACTH cut‐off of 35 pg/mL (or 50 pg/dL) had a sensitivity of 68.3% (70.9%) and a specificity of 58.5% (52.6%). During the fall months using an ACTH cut‐off of 100 pg/mL, the CSS had a 69.4% sensitivity and a 62.3% specificity. Based on this population of horses, delayed shedding and abnormal sweating were significant predictors of PPID+ status. Although pot‐belly/weight gain, regional adiposity, excessive thirst and recurrent infections are considered to be associated with PPID, odds ratios for each were <1.0. The CSS may be a viable option for veterinary practitioners to utilize to determine if evaluation of ACTH in a particular horse is necessary. For example, based on the results of this study, if only one of the following clinical signs are present: potbelly/weight gain, regional adiposity, excessive thirst or recurrent infections; evaluation of ACTH for PPID may not be recommended. Additional field‐based studies are essential to further evaluate the positive and negative predictive value of the CSS for PPID in horses. ABSTRACT E69 Efficacy of single active and combination anthelmintics against equine strongyles in adult horses Edwina Wilkes; Natalie Ford; Kristopher Hughes Charles Sturt University Cyathostomins are considered the most important strongylid parasites of the horse worldwide. Intensive interval treatment regimens have resulted in the development of widespread anthelmintic resistance in cyathostomins. It is imperative that existing anthelmintics are used judiciously and monitoring is undertaken for development of anthelmintic resistance (AR) and to ensure that effective drugs are utilized. The aim of this study was to evaluate the efficacy of abamectin (ABA), oxfendazole (OXF) and a commercially available combination anthelmintic (ABA+OXF) against strongyles in adult horses. Horses (>2 yo) resident at Charles Sturt University were screened for inclusion in the study. Fecal samples were collected from each horse and three fecal egg counts (FECs) were performed on each sample using the modified McMaster method. Thirty six horses with >50 strongyle epg were recruited into the study and randomly allocated into one of four groups on treatment day (day 0): ABA+OXF, ABA, OXF and an untreated control group. Post‐treatment FECs were determined on days 14, 21, 28, 35, 42, 49 and 56. Results from a single count (C1) and the average of three counts (X1‐3) were used to calculate the arithmetic means (AM) for FEC on day 0 and day 14. Fecal egg count reductions (FECRs) were calculated using the AM of individual FEC results, AM of arcsin‐transformed individual FECRs and correction of the AM of the treatment group FECR by changes in the AM of the control group FECR. A FECR <90% on d14 was considered to represent AR. Egg reappearance periods (ERP) were defined as the timepoint where FECR (calculated using AM of individual counts) was <90%. Using the results of C1 for FECRT, strongyles were susceptible to ABA+OXF (100%) and ABA (99.19–99.95%) and resistant to OXF (55.05–80.63%). Similarly, using the results of X1‐3, strongyles were susceptible to ABA+OXF (99.83–99.98%) and ABA (99.64–99.81%) and resistant to OXF (70.76–86.12%). The ERP for ABA+OXF, ABA and OXF was 49 days, 35 days and 14 days, respectively. The results of this study demonstrated that the ABA‐OXF combination was highly effective against benzimidazole‐resistant strongyles and there was also evidence of greater egg suppression compared to the single active anthelmintics. The shortened egg reappearance period following treatment with abamectin is considered to be an early indicator of macrocyclic lactone resistance development. The prudent use of anthelmintic combinations may contribute to more sustainable control of endoparasites in horses. ABSTRACT E70 Duration of effectiveness of frozen/thawed thyrotropin releasing hormone to stimulate ACTH release in horses Steven Grubbs 1; Kelley Jones2; Rhonda Hoffman3; John Haffner3 1Boehringer Ingelheim; 2Around the Bend Veterinary Services; 3Middle Tennessee State University The thyrotropin releasing hormone (TRH) stimulation of ACTH due to the increased sensitivity compared to measurement of basal ACTH has increasingly been used as a diagnostic test for pituitary pars intermedia dysfunction (PPID). Many equine practitioners will freeze doses of TRH, then thaw, and drive to the farm to examine the horse. If the horse owner declines testing, the veterinarian has TRH that has been frozen and thawed. Anecdotally, TRH can only be frozen and thawed once for optimum and consistent response. The potency and stability over time of TRH is unknown after one freeze thaw cycle. It would be useful for veterinarians to understand if thawed TRH stored at refrigerated temperature can produce accurate results when administered to a horse at a later date. This study was designed to determine the duration of effectiveness of TRH following one freeze/thaw cycle when stored at 5°C over time in horses. Ten horses (PPID+ and PPID‐) were enrolled, mean age 18.8 yrs (range 12 to 25 yrs). Horses were first paired by PPID status and randomized into 2 groups of 5 horses each prior to –Day 14. Thirty, 1 mg/ml doses of constituted TRH were frozen at −20°C on –Day 28. On –Day 14, ten doses of TRH were thawed at 5°C followed by thawing of the remaining (20 doses) TRH on Day 0. Thawed TRH was stored at 5°C until administration. On Day 0, all horses had blood collected for baseline ACTH (T0‐ACTH) followed by administration of 1 mg TRH IV. Blood was then collected exactly 10 minutes post‐TRH administration (T10‐ACTH). The TRH stimulation procedure was repeated with the thawed TRH on Days 14, 28, 42 and 56. In order to avoid potential carryover effects of multiple TRH stimulation procedures administered every two weeks, horses in Group 1 had the TRH stimulation repeated on Days 14 and 42 whereas Group 2 horses had the TRH stimulation repeated on Days 28 and 56 days TRH post‐thaw. All samples were centrifuged following collection and plasma was frozen (‐80C) until analysis at Cornell Animal Health Diagnostic Center. Data were analyzed using a mixed model with repeated measures to compare T10‐ACTH and the percent increase of ACTH after TRH stimulation, using horse as the subject and day as the repeated effect. Pearson's correlation coefficients were used to examine relationships between T10‐ACTH on Days 14, 28, 42, 56 to the T10‐ACTH on Day 0. There was no effect of Group (p > 0.25), so when appropriate, data were combined for analysis. There was no effect of Day post‐thaw on T10‐ACTH (p = 0.13) or the percent increase of ACTH after TRH stimulation (p = 0.36). Pearson's correlation coefficients indicated strong relationships between T10‐ACTH on Day 0 and all other days (R > 0.98, p < 0.001). The thyrotropin releasing hormone stimulation test produced repeatable ACTH concentrations in samples collected 10 min after administration of TRH in horses when using TRH that has been thawed and stored at 5°C for up to 56 days. ABSTRACT E71 Oclacitinib maleate (Apoquel) dose determination in horses with naturally occurring allergic dermatitis Marike Visser; Dawn Cleaver; Blair Cundiff; Vicky King; Gordon Sture Zoetis Oclacitinib maleate (Apoquel®) is a Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) inhibitor approved for use in dogs with atopic and allergic dermatitis. The efficacy and safety of two different oral dose levels (0.1 or 0.25 mg/kg) of Apoquel for the reduction of clinical signs of equine allergic dermatitis were evaluated in a randomized, placebo‐controlled, double‐masked, multicenter study. Horses were evaluated for pruritus (Days 0, 1, 2, 3, 5, 7, 14, 21, and 28) and skin lesions were scored (Days 0, 14, and 28) to establish a minimum effective dose. Once‐daily oral dosing occurred beginning on Day 0 through 28(+2). Fifty‐eight animals were randomized at an intended ratio of 1:1:1 into one of three treatment groups: T01 (0.0 mg/kg, placebo, n = 19), T02 (oclacitinib maleate, 0.1 mg/kg, n = 18), or T03 (oclacitinib maleate, 0.25 mg/kg, n = 21) at four veterinary practices in the United States. Horses were required to be >12 months and ≤ 20 years of age, weigh ≥200 kg, have at least “mild itching” (≥40 mm) according to the Owner Assessment of Pruritus Visual Analog Score (PVAS), have clinical signs of allergic dermatitis, and be otherwise healthy. The primary efficacy variable was the PVAS. A significant treatment difference (p ≤ 0.0938) was found for 0.25 mg/kg Apoquel compared to placebo beginning at Day 5 (i.e., Days 5, 7, 14, 21, 28). In addition, there was a significantly (p = 0.0844) greater reduction in the percent change from baseline in the PVAS compared to placebo for the 0.1 mg/kg Apoquel group at Day 28 (−43.4% vs −20.4%) and for the 0.25 mg/kg Apoquel group (p ≤ 0.0829) starting at Day 5 (−28.7% vs −12.4%) and continuing through Day 28 (−59.6% vs −20.4%). A comparison of the Lesion Score between placebo and 0.1 mg/kg Apoquel, and placebo and 0.25 mg/kg Apoquel detected no significant differences (p ≥ 0.1316). The Lesion Score mean percent change from Day 0 (baseline) was a decrease of 26.6%, 51.5%, and 63.0% at Day 28 for 0 mg/kg (placebo), 0.1 mg/kg, and 0.25 mg/kg, respectively, showing a dose‐dependent clinical improvement in skin lesions that was not significantly different (p ≥ 0.1495). Adverse events were considered typical for a population of horses with allergic dermatitis and no horses were removed from the study due to an adverse event. Clinical pathology summaries revealed no effects that appeared to be clinically significant or biologically important. The results of this study demonstrated the efficacy and safety of Apoquel for the treatment of pruritus in horses following oral administration of 0.25 mg/kg once daily for 28 days with onset of effect as early as 5 days after initiation of treatment. ABSTRACT E72 Effect of oral trazodone on intraocular pressure in healthy horses Alexandra Moss; Rachel Hritz; Rachel Hector; Kathryn Wotman Colorado State University Trazodone has been used successfully in other veterinary species to reduce anxiety and detrimental behaviors. It has been previously shown to elicit light sedation in horses when administered orally, therefore this medication may be used in horses that show anxiety while on stall rest. Prior literature regarding the effect of trazodone in humans and rabbits have identified potential ocular side effects; specifically, altered intraocular pressure (IOP) and vertical pupil diameter (VPD). This study evaluated the effect of oral trazodone on behavioral, physical, and selected ocular parameters in horses. Eight clinically normal horses (4 mares, 4 geldings, 9 ± 5) received a single 6 mg/kg oral dose of trazodone. Baseline heart rate, respiratory rate, rectal temperature, gastrointestinal borborygmi, level of sedation and IOP and VPD in both eyes were assessed prior to administration of the medication. All parameters were measured again at 0.5, 1, 2, 4, 6, 8, 12, and 24 hours post administration. Mild sedation was evident in 7/8 horses from 0.5 to 8 hours. Mean IOP was significantly decreased (7 to 4 mmHg) for the same period as sedation was apparent. Temperature was reduced from 1 hour to 8 hours. VPD was only significantly reduced (1.2 mm) at 0.5 hours after trazodone administration. All horses in this study reached plasma trazodone concentrations of >130 ng/mL, which is described for anti‐depressive effects in humans, and produced sedation in these horses. Trazodone alters ocular exam parameters in healthy horses, hence further research is warranted prior to its use in horses with ophthalmic disease. ABSTRACT E73 Fecal extract from obese horses induces inflammation in vitro Paige Roth 1; Jone Stanley2; Ana Chamoun Emanuelli2; Canaan Whitfield‐Cargile2 ; Michelle Coleman2 1College of Veterinary Medicine, Texas A&M; 2Texas A&M University The pathophysiology of obesity in horses is likely complex and multifactorial, though an association with an inflammatory state is postulated. The source of this inflammation, however, is unknown. Studies in human medicine suggest that the microbiome plays a role in mediating a chronic inflammatory response in obese people. The objective of this study was to evaluate whether the enteric microbiome from obese horses could induce an inflammatory response in murine macrophages. Feces obtained via rectal palpation from 14 obese (Body Condition Score (BCS) ≥7) and 14 non‐obese (BCS ≤5) horses residing on a single farm, with identical management practices, were included in the study. There was a significant (p < 0.05) increase in levels of lipopolysaccharide (LPS) and pro‐inflammatory cytokines Interleukin‐1β (IL‐1β), Tumor Necrosis Factor‐α (TNF‐α), and Interleukin‐6 (IL‐6) from macrophages treated with microbiome from obese horses compared to non‐obese horses. Overall, this study indicates that the microbiome likely plays a role in mediation of an inflammatory response. Further, the increased levels of inflammatory markers induced by microbiome of obese horses suggest important differences in the enteric microbial composition of these horses, compared to non‐obese animals, warranting further study. ABSTRACT E74 Effect of the proximal gastrointestinal tract on viability of equine probiotics: An in vitro study Ana Berreta; Trevor Alexander; Clark Kogan; Claire Miller; Jamie Kopper Washington State University Probiotics are defined as live microorganisms that confer a health benefit to the host when administered in adequate amounts, indicating that the presence of viable microorganisms is essential. Assessment of human probiotics indicates that without enteric coating few microorganisms survive the proximal gastrointestinal (GI) tract. The objectives of this study were to determine the effect of exposure to conditions consistent with the proximal GI tract on viability of commercially available equine probiotics, and to establish if increasing the gastric pH, consistent with use of a proton pump inhibitor, would improve viability of probiotics. We hypothesized that exposure to the proximal GI tract would decrease the viability of microorganisms in probiotics. A list of 53 commercially available equine probiotics was made, of which 11 were selected using a random number generator. The microbial contents were assessed using culture dependent techniques before and after exposure to a simulated equine proximal GI tract. Statistical analyses were performed using the Wilcoxon Rank Sum Test. Significance was set at p < 0.05. None of the products evaluated advertised the use of enteric protection. There was a significant reduction in the viability of microorganisms after exposure to conditions consistent with the proximal GI tract which, although still notable, was tempered by conditions consistent with use of a proton pump inhibitor. Results from this study suggest that, without enteric protection, the proximal GI tract has a negative impact on viability of microorganisms in commercially available equine probiotics. ABSTRACT E75 Pharmacokinetics of intravenous and intramuscular ceftazidime in neonatal foals Christina D. Marino 1; Clare Ryan2; Londa Berghaus3; Brenton Credille2; Virginia Fajt4 1Veterinary Teaching Hospital, University of Georgia; 2College of Veterinary Medicine, University of Georgia; 3University of Georgia; 4College of Veterinary, Medicine, Texas A&M University Cephalosporin antimicrobials are commonly used to treat septic foals when an aminoglycoside is contraindicated. Some cephalosporins have recently been unavailable because of manufacturing shortages. Ceftazidime is a third‐generation cephalosporin that has been used in clinical equine practice because of its expected coverage of gram‐negative bacteria, renal safety profile, and availability. However, the plasma disposition has not been evaluated in foals. The goal of this study was to estimate the pharmacokinetic parameters of single intravenous and intramuscular doses of ceftazidime in neonatal foals. Six healthy 2–3 day old foals were given single 25 mg/kg doses of ceftazidime intravenously (IV) and intramuscularly (IM) in a cross‐over design. The order of route of administration was randomly assigned with a 48‐hour washout period between doses. No adverse reactions were noted during treatment. Non‐compartmental analysis was used to estimate plasma pharmacokinetic parameters. The median T1/2 for IV and IM administration was 2.28 hours and 2.0 hours, and median AUC0 ‐ last was 317 (μg/ml)/hr and 350 (μg/ml)/hr, respectively. The median Cmax after IM administration was 100.6 μg/ml, with a median Tmax of 0.7 hours. There were no statistically significant differences between IV and IM pharmacokinetic parameters (p < 0.05). The 25 mg/kg dose of ceftazidime resulted in serum concentrations above the human CLSI Enterobacteriaceae susceptible breakpoint for 8 hours following IV and IM administration. Based on results of this study, IV or IM ceftazidime can be considered as an alternate third‐generation cephalosporin for use in neonatal foals. ABSTRACT E76 Pilot field study comparing the microbiome in horses with and without equine glandular gastric disease Linda J. Paul 1; Aaron Ericsson2; Frank Andrews3; Michael Keowan3; Michael St. Blanc3; Heidi Banse3 1School of Veterinary Medicine, Louisiana State University; 2University of Missouri; 3Louisiana State University The pathophysiology of equine glandular gastric disease (EGGD), a common disorder, remains poorly understood. A previous study using horses kept under identical management conditions showed gastric microbiome changes in association with EGGD. The objective of this study was to characterize the gastric microbiome in horses across multiple barns and differing management practices, to determine if differences between horses with and without EGGD persisted in a more varied population. It was hypothesized that differences in the microbiome would be associated with the presence of EGGD. Thirty client owned horses from various barns in the southern Louisiana area were enrolled. Gastroscopy was performed, EGGD grade was recorded, and pinch biopsies of endoscopically healthy glandular mucosa were collected. In horses with EGGD ≥2, biopsies of ulcerative lesions were also collected. Microbiome analysis was performed using the 16S rRNA gene. Microbial populations were compared by EGGD grade and barn. Biopsies with <1000 reads were excluded from analysis. No differences were detected between horses with and without EGGD, based upon similarity or diversity indices (p > 0.05). When horses were grouped by barn, differences were detected among groups using the Jaccard (p = 0.0001) and Bray‐Curtis (p = 0.0033) similarity indices. This was further supported by principal coordinate analysis. The influence of barn may be due to differences in management practices. Although no differences in microbial populations were observed with EGGD, this may be because of the small sample size and variability in gastric microbial populations among barns. Inclusion of additional horses may allow for identification of differences associated with EGGD. ABSTRACT E77 Pharmacokinetics of oclacitinib following oral and intravenous administration to horses Wendy Collard; John Thorn; Sarah Smith; Kenneth Feenstra Zoetis Apoquel® (oclacitinib maleate) is a Janus kinase inhibitor (JAKi) approved for the control of pruritus associated with allergic dermatitis as well as the control of atopic dermatitis (AD) in dogs. Allergic skin conditions can occur in other species such as cats and horses, with pruritus as a hallmark clinical sign that can lead to scratching and additional, self‐induced skin damage. The objective of this work was to characterize the single dose pharmacokinetics of oclacitinib in horses following intravenous (IV) and oral administration. Two studies were conducted. In one study four horses received intravenous 0.25 mg/kg oclacitinib. In the second study an average dose of 0.2 mg/kg was achieved in six horses dosed orally by administering multiple 16 mg tablets based on individual body weight. In both studies blood samples for plasma were serially collected for 72 hours post dose, and oclacitinib plasma concentrations were determined by LC/MS/MS. Following IV administration at 0.25 mg/kg, the clearance of oclacitinib was low (1.43 mL/min/kg), the volume of distribution was moderate (0.705 L/kg), and the half‐life was 9–10 hours. Following oral administration, oclacitinib was well absorbed with a mean Cmax of 204 ng/mL at a mean tmax of 3.7 hours. The oral half‐life of 9 hours was similar to the IV half‐life. In comparison to the half‐life observed in dogs (4 hours), the half‐life in horses is longer suggesting that once a day dosing could maintain the plasma concentrations needed to control pruritus in the horse. ABSTRACT E78 Safety of repeat gabapentin dosing (40 or 120 mg/kg) in adult horses Jenifer R. Gold; Tammy Grubb; Lais Malavais; Nicolas Villarino Washington State University Background: Neuropathic pain, as in laminitis, is largely refractory to standard analgesia. Gabapentin controls neuropathic pain in other species and may be effective in horses. Significant gabapentin‐mediated pain relief is unproven in horses, however, possibly due to insufficient dosing, as the effective dose is unknown. Our previous study showed that horses, like humans, have disproportional absorption of gabapentin. However, the absorption is more proportional than in humans, and the absorption disparities are likely due to inter‐horse variation. The proportionality is important as it allows a dosing recommendation based on linear pharmacokinetics but, single‐dose proportionality studies do not allow evaluation of safety using a valid therapy length for neuropathic pain. Prior to initiating pharmacodynamic studies in painful horses, safety of an appropriate dosing regimen for laminitis of at least two weeks is required. With repeat gabapentin dosing in other species, adverse effects include; sedation/ataxia in multiple species and rarely acute liver injury and exacerbation of chronic renal disease in humans. No adverse effects have been reported in horses. Methods: In a randomized cross‐over study using 6 adult horses, each. Horse received a dose of 40 mg/kg (Trial 1) and 120 mg/kg (Trial 2) of gabapentin orally twice daily prior to eating. The horses had a 3‐week washout in between doses. The horses had physical examinations, ataxia and sedation scores performed 3 times daily for 15 days. Biochemistry profiles were analyzed prior to initiation of (pregabalin), 7 and 14 days after the first gabapentin dose. Data were analyzed using Chi‐Square, student‐t tests and ANOVA, as required by data type. Significance was set at (p < 0.05). Results: Over the 2‐week study period none of the horses became sedate or ataxic with either dose of gabapentin. Biochemistry variables remained within normal limits. There were no significant differences within or between horses nor within or between trials for any variable. Conclusion: Repeat dosing of gabapentin is safe when dosed at 40 or 120 mg/kg twice daily for two weeks.   ABSTRACT E79 Pulmonary disposition of gallium maltolate after oral administration to foals Natalia Rodriguez 1; Noah D. Cohen1; Robert J. Taylor2; Lawrence R. Bernstein3; Angela I. Bordin4 1Texas A&M University; 2College of Veterinary Medicine and Biomedical Sciences, Texas A&M University; 3Gallixa LLC.; 4Equine Infectious Disease Laboratory, TAMU Emergence of isolates resistant to macrolides and rifampin creates great need for alternative antimicrobials for treating foals with Rhodococcus equi pneumonia. We have demonstrated in vitro, ex vivo, and in vivo activity of gallium maltolate (GaM) against R. equi. Although serum pharmacokinetics of GaM in foals have been reported, its pulmonary disposition following oral administration is unknown. It is important to determine the pulmonary disposition of GaM because virulent R. equi infect and replicate in alveolar macrophages after inhalation. Our objective was to characterize the pulmonary disposition of GaM in foals following a single oral dose. We hypothesized that oral administration of GaM would achieve concentrations exceeding the minimum inhibitory concentration (MIC) against R. equi in broncho‐alveolar lavage (BAL) cells. Eight university‐owned Quarter‐Horse foals 4 months of age were studied. BAL fluid and cells were collected at time 0, 4, 8, 24, and 48 hours after GaM administration. Concentrations of GaM in the serum, BAL fluid, and BAL cells were determined by inductively coupled plasma‐optical emission spectrometer or mass spectrometer, depending upon concentration. Time to maximum concentration (Tmax) for BAL fluid was 24 hours, and concentrations were below the MIC at all times. The Tmax in BAL cells was 48 hours and concentrations were above the MIC by 4 hours. Results indicated that GaM achieves therapeutic concentrations in BAL fluid cells, warranting evaluation for treating clinical pneumonia caused by R. equi in foals. If accepted for presentation, serum pharmacokinetics from these foals also will be reported. ABSTRACT E80 The value of transabdominal ultrasound in horses presenting with medical gastro‐intestinal disease Gayle D. Hallowell 1; Carolyn Bates2; Emma Peal3; Caroline Bullard3; James Bailey4; Adam Redpath4; Mark Bowen4 1School of Veterinary Medicine and Science, University of Nottingham; 2Defence Animal Training Regiment; 3Royal Army Veterinary Corps, Household Cavalry Mounted Regiment; 4SVMS, University of Nottingham To evaluate the frequency with which abnormalities are detected using transabdominal ultrasound in horses that present with weight loss, chronic diarrhea, pyrexia of unknown origin or recurrent bouts of abdominal pain. Clinical and ultrasound case records were searched for abdominal evaluations over the period of 2015–2020 in horses >1 year of age. Signalment, ultrasound findings and final diagnoses were recorded as was outcome. Abnormalities recorded from abdominal ultrasound included: increased small (SI) or large intestinal (LI) wall thickness defined as >4 mm, abnormal intestine, abnormal appearance or volume of peritoneal fluid or abnormal abdominal organ or other. Other information recorded included specific intestinal wall thickness, other tests performed, treatments administered and any further findings. Recurrent colic was classified as >3 episodes in 3 months and chronic diarrhea of >7 days duration. Images were obtained using a Vivid Q ultrasound machine (GE Healthcare) using both a 3 MHz convex and 7.5 MHz microconvex probes and saved as cineloops that were evaluated offline. 224 evaluations were found that had both abdominal ultrasound images and clinical reports or records. Horses ages ranged from 3–28 (13.5 ± 4.8 years), were predominantly TB/part‐breds (29%) or ID/part‐breds (29%) with 59% geldings and 41% mares. 61% of evaluations were for horses with weight loss, 24% with recurrent colic, 9% with diarrhea and 6% with other signs. Abnormalities were identified in 80% of examinations. Of those with abnormalities, 19% had thickened SI, 40% thickened LI, 21% thickened SI and LI, 4% abnormal motility, 8% abnormal peritoneal fluid and 8% with other abnormalities. Transabdominal ultrasound can identify abnormalities in a large percentage of horses that present with these clinical signs, making the time spent performing this technique worthwhile. ABSTRACT E81 Effect of neonatal dysphagia on subsequent racing performance in standardbred horses Barbara Delvescovo 1; Kathleen Mullen2; Steven Eicker3; Dorothy Ainsworth1 1Cornell University; 2Littleton Equine Medical Center; 3Valley Agricultural Software King Ferry We previously reported on a clustering of dysphagic foal cases occurring over a 5‐year period (2012–2016) on a Pennsylvania (PA) Standardbred broodmare farm located among fracking operations (Mullen et al., JVIM 33:2392, 2019). Another Standardbred broodmare farm located 250 miles away in New York (NY), owned by the same individual and operated identically, failed to experience similar cases of foal dysphagia over that same period. That investigation uncovered high concentrations of polycyclic aromatic hydrocarbons (PAHs) in the well water. We attributed the foal dysphagia to PAH exposure of late pregnant mares as the dysphagia prevalence was eliminated after a water filtration/treatment system (WFTS) was installed on the farm in August 2015. We were unaware of studies examining the effects of neonatal dysphagia on athletic performance and undertook the current investigation. We hypothesized that racing performance of formerly dysphagic foals would be negatively impacted. This prospective study was conducted from 2014–2017 evaluating foals born on the PA and NY farms; additional data were obtained from detailed farm records of foals born in 2012 and 2013. Foals (N = 8) with dysphagia attributed to causes other than PAH environmental exposure (e.g. prematurity, sepsis, neonatal encephalopathy, selenium deficiency, palatal congenital abnormalities) were excluded from our analysis. The proportion of foals from both farms that raced, their age of first race and two custom‐designed performance indices, Earnings Per Start Index (EPS) and Speed Index, were compared between the dysphagic and normal foals using Chi‐Square and Wilcoxon Rank Sum Tests with p < 0.05. 126 foals were born alive during the study period: 74 on the NY farm and 52 on the PA farm. Ten foals died prior to race training from causes unrelated to dysphagia, leaving 116 horses in the study. On the PA farm, 54% of unaffected and 72% (13/18) of the dysphagic foals raced; 70% (47/67) of the normal NY foals raced. Comparative analysis between the two farms revealed no significant difference in these percentages (p = 0.27). Installation of the WFTS on the PA farm did not affect the percentage of foals that eventually raced (p = 0.71). Performance analysis revealed no difference in the EPS, Speed Indices or age of first race between dysphagic and normal foals when either compared between (NY vs PA) or within (PA) farms (p > 0.05). Our results suggest that although treatment of neonatal dysphagia incurs a financial burden for the owners, the athleticism of formerly dysphagic foals does not appear to be negatively impacted as measured by EPS and Speed indices. ABSTRACT E82 Effects of supplements containing turmeric and devil's claw on equine gastric ulcer scores in horses Frank M. Andrews 1; Heidi Banse2; Michael St. Blanc2; Mary Retif2; Nicole Arana‐Valencia2; Michael Keowen2; Frank Garza2; Lydia Gray3; Chin‐Chi Liu2 1Equine Health Studies Program, Department of Veterinary Clinical Sciences, LSU; 2LSU School of Veterinary Medicine; 3SmartPak Equine Supplements commonly fed to horses to decrease inflammation and pain might cause or worsen gastric ulcers. The purpose of this study was to determine if a supplement containing turmeric (TUM; Curcuma longa) and devil's claw (DC; Harpagophytum species) caused worsening of gastric ulcer scores in stall confined horses. Twelve clinically healthy adult Thoroughbred horses with Equine Gastric Ulcer Syndrome (EGUS) scores >0 were included in a non‐crossover study design. Horses were stratified by EGUS score and assigned to either the treatment (TUM/DC supplement) or control (supplement without TUM/DC) group. The supplements were fed daily for 28 days. Gastroscopy was performed on days 0, 14, and 28. The EGUS score, non‐glandular ulcer number (NGN) and severity (NGS) scores and glandular number (GN) and severity (GS) scores were recorded. In addition, body weight, gastric juice pH, packed cell volume (PCV), total protein (TP), and results of a point‐of‐care blood analyzer were evaluated on Day 0 and Day 28. A mixed ANOVA model in SAS was used to analyze the variables measured with treatment, day and their interactions. Assumptions of these models (linearity, normality of residuals, and homoscedasticity of residuals) and influential data points were also assessed by examining standardized residual and quantile plots. When a fixed effect was detected, Tukey post‐hoc comparisons were performed with least square means for the effect. Significance was set at p < 0.05. Mean EGUS and NGS scores were significantly lower in both treatment and control groups by Day 14 and 28, when compared Day 0. Blood parameters, body weight, and gastric juice pH did not change significantly change during the study. In conclusion, a supplement containing turmeric and devil's claw did not result in worsening of gastric ulcers or alter health parameters after 28 days of feeding. ABSTRACT E83 Multidimensional analysis of bronchoalveolar lavage cytokines reveals interferon‐Γ as a key biomarker in equine asthma Jane S. Woodrow 1,2; Melissa Hines1; Carla Sommardahl1; Bente Flatland1; Kaori Davis3; Yancy Lo2; Zhiping Wang2; Mary Katherine Sheats3; Elizabeth Lennon2 1University of Tennessee; 2University of Pennsylvania; 3North Carolina State University Equine asthma syndrome (EAS) consists of two broad groups, defined as: mild to moderate (mEAS) and severe (sEAS). Each group remains a heterogenous population with continued need to clarify their pathogenesis. The role of pro‐inflammatory cytokines, both type 1 and type 2 cytokines, in addition to anti‐inflammatory cytokines, such as transforming growth factor (TGF)β‐1 and bone morphogenetic proteins (BMP), need to be further elucidated in EAS groups in order to best mange and treat the patient. The objectives of this study were to: (1) analyze the cytokine profile present in BALF that defines endotypes of equine asthma, and (2) analyze anti‐inflammatory molecule gene expression levels in immune cells of the BALF. Cytokine concentrations in BALF supernatant was evaluated with a commercially available multiplex immunoassay. Multidimensional scaling (MDS) analysis was performed in order to visualize on a two‐dimensional figure the clustering of samples based on age, sex, cytokine concentrations, and neutrophil percentage. Gene expression results were normalized to β‐actin and relative quantification was performed using 2‐ΔΔCt method. BALF multiplex showed that horses with asthma had significantly higher TNFα (mEAS: 6.54 [4.79–7.69] pg/mL, p = 0.013; sEAS: 11.31 [3.67–21.77] pg/mL, p = 0.0009) concentrations compared to healthy horses (2 [0.8–3.63] pg/mL); as well as significantly elevated CXCL8 (mEAS: 14.41 [8.74–22.48] pg/mL, p = 0.024; sEAS: 19.83 [16.86–27.82] pg/mL, p < 0.0001), concentrations compared to healthy horses (4.54 [1.26–8.88] pg/mL). Additionally, IFNγ was significantly elevated in sEAS (35.28 [21.08–75.45] pg/mL, p = 0.012) compared to healthy horses (21.08 [21.08–21.08] pg/mL). MDS analysis demonstrated that IFNγ differentiates severe from moderate asthma, and that TNFα and CXCL8 are key biomarkers of equine asthma endotype. Tgfβ1 was significantly increased in mEAS immune cells versus healthy (p = 0.02), and although statistical differences were not seen in BMP7 expression, a subset of horses diagnosed with sEAS had markedly elevated BMP7 expression. Elevated BMP7 in a subset of sEAS horses may signify over exuberant response to counteract airway remodeling and fibrosis due to BMP7's ability to block Tgfβ1‐driven fibroblast activation. These results will help further define EAS immunopathology, which could improve understanding of asthma endotypes, and potentially identify novel therapeutic strategies. ABSTRACT E84 A retrospective study of exercise‐induced pulmonary hemorrhage and asthma in barrel racing horses in Texas Laszlo Hunyadi 1; Munashe Chigerwe2; Emily Sundman3 1Texas Tech University; 2University of California Davis; 3Equine Sports Medicine & Surgery This study was to evaluate the bronchoalveolar lavage (BAL) fluid cytological results of barrel racing horses with exercise‐induced pulmonary hemorrhage (EIPH), asthma, or both. A retrospective study was conducted of 95 horses diagnosed with non‐infectious respiratory disease and BAL results at a private practice in Texas. EIPH only was diagnosed in 28/95 (30%) BAL samples, asthma only was diagnosed in 25/95 (26%) BAL samples, and EIPH and asthma was diagnosed in 42/95 (44%) BAL samples. A history of EIPH was not predictive of a diagnosis of EIPH, or asthma. Of the BAL results consistent with asthma only, the primary elevated cell type was mast cell; followed by samples with both elevated eosinophils and mast cells. No cytological differences in frequency of elevated inflammatory cell types were found between horses diagnosed with EIPH and those without a diagnosis of EIPH. The study showed a substantial percentage (44%) of the horses examined had evidence of both EIPH and asthma on BAL cytologic evaluation. Comorbidities of EIPH and asthma is a common diagnosis in barrel racing horses in this study. ABSTRACT E85 Clinical response in horses with severe equine pasture asthma to allergen specific immunotherapy Ann Chapman 1; Michelle Woodward O’Gorman2; Mike Keowan2; Frank Garza2; Frank Andrews2 1Louisiana State University; 2School of Veterinary Medicine, Louisiana State University Severe equine pasture asthma (EPA) is a debilitating respiratory condition of grazing horses in the southeastern U.S. The condition is characterized by airway inflammation, bronchial hyper‐reactivity, chronic cough and dyspnea. This disorder has a strong association with hot and humid climate and high environmental fungal spores and grass pollens. The goals of this study were to collect intradermal and serum allergy test results from horses with severe EPA, and to evaluate clinical responses to allergen specific immunotherapy, formulated based on both test results, over the course of one year while allowing continuous exposure to pasture aeroallergens. Seven university owned horses with severe equine pasture asthma were enrolled in the study based on BAL inflammation and clinical scoring system (presence of tachypnea, nostril flaring, abdominal lift, spontaneous or inducible cough, nasal discharge, abnormal tracheal sounds, and abnormal pulmonary auscultation during summer months). All horses underwent serum and intradermal allergy at the onset of expected clinical remission (November). Horses were randomly assigned to either treatment group (n = 4) or controls (n = 3) and were housed together on mature grass pastures for the duration of the study. Horses within the treatment group received subcutaneous injections of dilutions of selected allergens over the course of the study using a standard protocol (Table 1). Standing thoracic radiographs and bronchoalveolar lavage cytology were performed on all horses on prior to starting therapy, and then approximately at days 90, 180, 270, and 365. Horses were observed daily and evaluated at pre‐determined intervals using the established clinical respiratory scoring system by blinded evaluators. Horses that exhibited severe exacerbation of clinical disease were administered short term rescue therapy. Total clinical scores improved significantly in both groups (p < 0.05) during the remission period (Day 28) and worsened during the exacerbation season (Day 85–270). A time effect was noted in mean BAL neutrophilia (43.3% ± 30.6) in all horses (p < 0.05). There was no significant difference in total clinical scores and BAL neutrophilia between treatment groups. In conclusion, allergen specific immunotherapy alone did not improve clinical score or BAL inflammation in horses with equine pasture asthma following a year of therapy. Future larger studies examining allergen specific immunotherapy, potentially over longer periods of time in younger animals, along with environmental management in horses with EPA are warranted. Table 1. ASIT treatment protocol Day Vial 1 Vial 2 Vial 3 1 0.1 ml 3 0.2 ml 5 0.4 ml 7 0.8 ml 9 1 ml 11 0.1 ml 13 0.2 ml 15 0.4 ml 17 0.8 ml 19 1 ml 21 0.1 ml 23 0.2 ml 25 0.4 ml 27 0.8 ml 29 1 ml 39 1 ml 59 1 ml Continue every 3 weeks until respiratory flare. Every 14 days when flaring begins.   18 19 ABSTRACT F01 The effect of potassium levels on electrocardiographic data in calves with neonatal diarrhea Osman Safa Terzi 1; Erdal Kara2; Ece Irmak Alpsoy2; Demet Ayhan2; Bensu Merve Arikan2; Hasan Albasan3 1Department of Internal Medicine, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey; 2Ankara University; 3Pet Depot Veterinary Group Hyperkalemia in newborn calves with diarrhea can result in severe cardiac rhythm abnormalities. The purpose of present study was to evaluate the potassium levels along with electrocardiographic (ECG) data in 36 calves (age < 30 days) with neonatal diarrhea from 3 different dairy farms during December 2019 in Ankara, Turkey. Of 36 calves, 14 had hyperkalemia and 22 had normokalemia. Hyperkalemic calves (cK+: 5.84–8.33) had significantly (p = .0001) deeper T wave in lead II than calves with cK+ within the reference range. There was no significant difference in P, R, S amplitudes, P, QRS, T durations, PR intervals, or any other ECG findings between hyperkalemia and normokalaemia of calves with neonatal diarrhea. Acidemia and metabolic acidosis frequently evident in the calves with hyperkalemic diarrhea that were reported with cardiac rhythm abnormalities in the previous studies. On the other hand, in the present study, hyperkalemic neonatal calves with diarrhea had only deeper T wave but no other abnormalities; however, acidemia and metabolic acidosis were not severe. Holter monitoring should be warranted for hyperkalemic calves with diarrhea. ABSTRACT F02 Obstipation in pet pigs presented to a university teaching hospital: 20 cases Kallie J. Hobbs; Diego Gomez; Sally DeNotta; Aitor Gallastegui University of Florida The aim of this retrospective study was to describe the signalment, history, clinicopathologic and diagnostic imaging findings, and post‐mortem lesions in 20 pet pigs diagnosed with obstipation at a university teaching hospital. Treatments and clinical outcomes are also discussed. Medical records of pet pigs admitted to the Large Animal Hospital at the University of Florida between 2007 and 2019 were reviewed for a diagnosis of obstipation. Obstipation was defined as the absence of feces for 48 hours or greater, with evidence of intestinal distention from gas or fecal accumulation in the rectum and/or distal colon on either computed tomography (CT) or radiographs (RD). Data was collected regarding clinical signs, hematologic and biochemical profiles, blood gas analysis (BG), and diagnostic imaging findings from the date of admission. Information on treatments, if surgery was pursued, duration of hospitalization, and clinical outcome was recorded. Range and median were used to describe population characteristics. Twenty cases met the inclusion criteria. At the time of diagnosis of obstipation, the most frequently observed clinical signs were lethargy (n = 20, 100%), anorexia (n = 19, 95%), tachypnea (n = 16, 80%), vomiting (n = 12, 60%), tachycardia (n = 10, 50%) and decreased appetite (n = 2, 10%). Hematologic abnormalities included lymphopenia (<5.30 k/μL, n = 17, 85%), leukopenia (<11 k/μL, n = 8, 40%), and toxic changes in neutrophils (n = 8, 40%). Biochemical alterations included hypokalemia (<4 mEq/L, n = 12, 60%) and hypoglycemia (<65 mg/dL, n = 6, 30%). The most common diagnostic imaging findings included moderate gastric distention (n = 13, 65%), gas‐distended small intestinal loops (n = 10, 50%), and moderate amounts of ingesta throughout the gastrointestinal tract (n = 17, 85%). All 20 pigs had a combination of two or more of these findings. Medical therapy consisted of fluid therapy via intravenous/rectal/oral, combination intravenous/oral or combination rectal/oral in all cases. Additional therapies included antimicrobial therapy (n = 17, 85%), non‐steroidal anti‐inflammatory drugs (n = 11, 55%), carbonated soda beverage (n = 6, 30%), exploratory laparotomy (n = 6, 30%), and anti‐emetics (n = 3, 15%). Of the 20 pigs, 14 (70%) were discharged from the hospital and 6 (30%) were euthanized. The median time of hospitalization for surviving pigs was 3 days (range: 2–7 days). The median time of hospitalization for pigs that underwent surgery and survived was 5 days (range: 3–6 days) whereas the median time of hospitalization for pigs that were managed medically was 3 days (range: 0.8–7 days).The median time of hospitalization for non‐surviving pigs was 24 hours (range 0.5–3 days). Based on the observations in this study, obstipation in pet pigs carries a moderate to good prognosis. Diagnostic imaging findings such as moderate gastric distention and moderate amounts of ingesta throughout the gastrointestinal tract are commonly identified on CT or radiographs of obstipated pigs. Leukopenia, lymphopenia and hypokalemia were the most common blood work abnormalities present in the pigs included in this study. ABSTRACT F03 Influence of sample volume and time on rumen juice analysis in cattle Suzanne A. C. Clergue 1; Sarah Depenbrock2; Munashe Chigerwe2 1Large Animal Hospital, VMTH, UC Davis; 2School of Veterinary Medicine; UC Davis Literature describing rumen juice (RJ) analysis as a diagnostic tool is based on analysis of a 10 mL sample directly after sampling. However, it may be challenging to obtain 10 mL of RJ from some patients, and clinical circumstances may delay the RJ analysis. This study quantified the effect of sample volumes, 2, 5, 10, 50 and 100 mL; and time‐to‐analysis on RJ analysis after 30 and 60 minutes (min). Two liters of RJ were obtained from a cannulated donor cow 21 times. The samples were subdivided into 1 set per time point. A set was composed of 2 duplicates of each sample volume. Samples were analyzed at 0, 30, and 60 min after sampling. Analysis of RJ consisted of pH, methylene blue reduction time (MBRT), and protozoal motility scoring. At 30 and 60 min, pH of the 2 mL and 5 mL samples were significantly (p < 0.05) higher than pH of the 10 mL, 50 mL, 100 mL samples. The MBRT was significantly prolonged for 2 mL samples compared to 10, 50 and 100 mL samples at all time points. The pH and MBRT at 60 min were significantly higher than at 0 min for all sample volumes. There was no significant difference in protozoal motility for all sample volumes at all times. This study indicates that the interpretation of RJ analysis may be altered by sample volumes less than 10 mL or 30 to 60 min delays in analysis. ABSTRACT F04 An alternative approach to evaluating brix refractometer performance for assessment of beef colostrum quality Lisa Gamsjaeger 1; Ibrahim Elsohaby2; Jennifer Pearson1; Michel Levy Ibrahim Elsohaby1; Deborah Haines2; Edmond Pajor1; Claire Windeyer1 1University of Calgary; 2Western College of Veterinary Medicine The Brix refractometer is a practical tool that can be used to assess colostral Immunoglobulin G (IgG) concentration, but studies evaluating its performance in beef colostrum and identifying appropriate thresholds to detect low‐IgG colostrum are sparse. The objective of this study was to assess Brix refractometer performance for estimating beef colostrum IgG concentrations, focusing on determination of the threshold for identification of colostrum containing <100 g/L IgG. A total of 416 beef colostrum samples from 11 cow‐calf operations in Alberta, Canada, were available for this retrospective study. The IgG concentrations were measured by radial immunodiffusion (RID, Lab A = 416) and estimated by Brix refractometry in three different laboratories to allow assessment of interlaboratory agreement (Lab A = 364, Lab B = 271, Lab C = 220). A Spearman correlation coefficient was assessed between RID and Brix (Lab A) results. Interval likelihood ratios were calculated to determine the best Brix threshold for detecting colostrum containing <100 g/L of IgG. Optimal thresholds were also evaluated using the misclassification cost‐term term approach with different possible prevalences of low‐IgG colostrum and different plausible ratios of false‐negative to false‐positive costs. Test characteristics were calculated for the selected threshold. Concordance correlation coefficients (CCC) among Brix results of the three laboratories were determined and Bland‐Altman analysis was performed to assess interlaboratory agreement. The mean colostrum IgG concentration was 149.6 ± 38.7 g/L. Brix refractometry and RID results were positively correlated (r = 0.72). A threshold of <24% Brix was best for detecting colostral IgG concentrations of <100 g/L. For most considered scenarios, using a threshold of 24% Brix was also economically beneficial. Sensitivity, specificity and accuracy at this threshold were 88.9%, 91.3% and 91.2%, respectively. The CCC among Brix values measured at the three laboratories was high (Lab A/B: CCC = 0.89; Lab A/C: CCC = 0.96; Lab B/C: CCC = 0.96) and Bland Altman analysis showed small mean differences (−1.2 to 0.09% Brix) and narrow limits of agreements (−4.8 to 2.4% Brix) among laboratories. In conclusion, Brix refractometer performance for assessment of colostral IgG concentrations in beef colostrum was good. The use of Brix refractometry can therefore be recommended to aid colostrum management decisions on farms. Beef calves whose dams have colostrum Brix values of <24% may require larger volumes of colostrum and/or benefit from supplementation with colostrum from a different dam or a commercially available colostrum supplement. ABSTRACT F05 Bacterial culture and susceptibility of samples taken from septic foot lesions of adult beef cattle Kelsey E. Walker 1; Tamara Gull2; John Middleton1; Pamela Adkins1 1Veterinary Health Center, University of Missouri; 2Veterinary Medical Diagnostic Laboratory, University of Missouri Lameness in cattle can have a major impact on animal welfare and producer profits. The purpose of this study was to determine the most common bacterial species associated with sole abscess and deeper septic processes of the foot in beef cattle, and to determine antimicrobial susceptibility patterns of the cultured microorganisms. Adult beef cattle that presented to the University of Missouri Food Animal Clinic and were diagnosed with a sole abscess or deep digital sepsis were enrolled. Exudate was sampled using a bacterial culture swab (ESwab, Copan Diagnostics, Murrieta, CA) during assessment of the lesion. The exudate was aerobically and anaerobically cultured, isolates were identified using matrix‐assisted laser desorption/ionization time of flight mass spectrometry, and antimicrobial susceptibility was performed using Sensititre plates (Sensititre BOPO6F Vet AST Plate, Thermo Fisher Scientific, Waltham, MA). To date, 31 samples from 31 cattle have been collected, and 134 bacterial isolates have been grown in culture. Most samples (28/31) had polymicrobial growth, with a median number of five isolates per sample (range: 1–13). Trueperella pyogenes, Escherichia coli, and Streptococcus uberis were the most commonly isolated bacteria, but over forty species have been identified. Susceptibility profiles (n = 15) of the most commonly isolated bacterial species revealed that most (12/15) were pansusceptible to tested antimicrobials. Resistance to oxytetracycline and tulathromycin was noted in 3 of 9 Trueperella pyogenes isolates. Results suggest that bacteria isolated from septic foot lesions are primarily opportunistic pathogens that are generally susceptible to commonly used antimicrobials in food animal practice. ABSTRACT F06 Sudden death in weaned lambs and calves due to Strongyloides papillosus in the United States Toby L. Pinn‐Woodcock 1 ; Gerald Duhamel1; Manigandan Lejeune2; Belinda Thompson2 1College of Veterinary Medicine, Cornell University; 2Cornell Animal Health Diagnostic Center The Cornell Animal Health Diagnostic Center (AHDC) has confirmed two outbreaks of sudden death in apparently healthy weaned dairy calves in New York associated with the nematode, Strongyloides papillosus. While S. papillosus is known to cause symptoms of ill thrift and diarrhea in young ruminants, these are the first United States reports describing an association with sudden death of weaned calves raised in confinement housing. Researchers previously linked S. papillosus hyperinfection to sudden death in weaned calves and lambs in Japan, and suggested sudden death caused by S. papillosus is secondary to fatal arrhythmias, often without significant findings on post‐mortem exam. To further investigate the prior occurrence of bovine and ovine sudden death associated with S. papillosus in the United States, anamnestic animal data, post‐mortem and ancillary diagnostic results from ovine and bovine cases submitted to the AHDC with a history of sudden death and S. papillosus ova detection on fecal examination were evaluated from 2007 through 2019. A total of 10 cases were identified meeting the inclusion criteria, consisting of 2 bovine and 8 ovine cases. Five of these cases (50%) had open post‐mortem diagnoses and clinical presentations similar to those previously described in Japanese S. papillosus outbreaks, including weaned juveniles (3 lambs; 2 calves) during the late summer and fall. These cases originated from New York state (n = 4) and Massachusetts (n = 1) and had S. papillosus fecal egg counts ranging from 3,100 to 29,000 eggs per gram. The remaining 5 cases identified had definitive post‐mortem diagnoses, including bronchopneumonia, Clostridium novyii hepatitis, listeriosis, haemonchosis, urolithiasis, abomasitis, meningitis and enteritis, with S. papillosus fecal egg counts ranging from 2 to 1,250 eggs per gram. These findings suggest that cases of sudden death associated with the presence of S. papillosus may have been previously given an open post‐mortem diagnosis at the AHDC. S. papillosus should be considered a novel differential diagnosis for sudden death in weaned lambs and calves in the northeastern United States. ABSTRACT F07 Urine acidification using oral methionine in miniature pigs Rachel E. Oman; Pamela Adkins; Corrinn Bromfield University of Missouri Obstructive urolithiasis is a life‐threatening condition affecting miniature pigs yet there is limited information regarding medical management of the condition in this species. The objective of this study was to determine the effect of oral methionine on urine pH in miniature pigs. A prospective crossover study design was used. Methionine (VET Pharmaceuticals, Miramar, FL) was administered orally every 24 hours for six days at 100, 200 and 300 mg/kg to twenty male, juvenile, intact miniature pigs. All pigs were individually housed and fed Mazuri mini‐pig active adult diet (Mazuri Exotic Animal Nutrition, St. Louis, MO) at 2% of body weight. Urine pH was measured twice daily on free‐catch urine samples. Serum electrolytes and renal enzymes were monitored for evidence of systemic acidification or electrolyte abnormalities. The urine pH decreased significantly when administered at 100 mg/kg (p < 0.03) and 300 mg/kg (p < 0.02) with a mean decrease of 0.52 and 0.50, respectively. All pigs remained systemically healthy throughout the study. Oral methionine appears to be a safe and effective means of acidifying urine in miniature pigs. The degree of acidification achieved in this study may not be sufficient to dissolve uroliths in clinical cases of obstructive urolithiasis. However, oral methionine has potential to serve as a component of medical management of obstructive urolithiasis in miniature pigs. ABSTRACT F08 One‐year cross‐sectional study of dermatological lesions in 433 dairy cattle in a veterinary teaching hospital Eloi Guarnieri; Frédéric Sauvé; David Francoz Faculté de Médecine Vétérinaire, Université de Montréal Little literature is available on the prevalence of bovine skin diseases. The objective of this study was to describe the dermatological lesions (DL) in dairy cattle admitted at the Faculty of Veterinary Medicine (FVM), Université de Montréal, from July 1, 2018, to June 30, 2019. A study‐dedicated dermatological lexicon was first developed by the authors. Over a year, all dairy cattle admitted at the FVM were included in the study. Dairy cattle readmitted or without integumentary examination within 48 hours of admission were excluded. DL involving feet and ear canals were also excluded. The morphological and location of the skin and the oral mucosal DL were recorded by a trained observer. On the 610 cattle admitted at the FVM, 433 dairy cattle were included. Most of them were Holstein breed (90%) and females (98%). The mean age was 3.3 years old (+/− 2.8 years). Of these 433 cattle, skin and oral mucosal lesions were observed in 91% and 9% of the cases, respectively. Most cattle had at least one hock (55%), one carpus (47%) or one stifle (23%) affected. Crusts (55%), callus (54%) and alopecia (51%) were the most common skin DL. Erosions (43%) and ulcers (20%) were the most common oral mucosal lesions. This cross‐sectional study highlighted the high prevalence of the DL in this specific cattle population. Considering these results, further studies would be important to determine etiologies, economic and clinical impacts of these DL. ABSTRACT F09 Arrival risk factors associated with morbidity in milk and grain fed veal calves in Québec Abdelmonem Mohamed; Julie Berman; Sébastien Buczinski; Simoun Dufour; David Francoz Faculty of Veterinary Medicine, Montreal University Inadequate transfer of passive immunity (TPI), arrival weight, seasons, purchase price and calf suppliers are important determinants of morbidity and mortality in veal calves. The objective of this prospective cohort study was to identify the risk factors, already present at arrival, and associated with subsequent individual treatment in Québec's veal calves. Thirty calves were randomly enrolled in each of 59 milk and grain fed veal lots. Blood samples were collected during the 1st week after arrival and evaluated using the brix refractometer (adequate TPI if ≥8.4%). Data regarding arrival weights, purchase price (CAD/pound), origin, arrival season and feed (milk‐fed or grain‐fed veal) were recorded upon arrival. Mortality, individual treatments and slaughter weights were obtained at the end of each production cycle. Generalized linear mixed models were used to analyze the association between morbidity (1 or more individual antimicrobial treatment) as a dependent variable and the different risk factors as predictors while controlling putative confounders. A total of 1,668 calves were included, and 432 calves were individually treated. In the multivariable model, treatment odds were higher in calves with failure of immunity transfer with odds ratio [OR] 1.5 (95% confidence interval [CI] 1.15–2.15, p = 0.004). An interaction between season and arrival weight was found. Interestingly, calves weighing between 42.5 and 45.5 kg arriving in winter had lower odds of treatment than heavier calves arriving in the same season (p = 0.01). We will evaluate the impact of those different risk factors on odds of mortality and on average daily gain during the feeding period. ABSTRACT F10 Clinical and necropsy findings associated with increased risk of natural death in critically‐ill neonatal crias Erica Dorsey 1; Daniela Bedenice2 1Becker College; 2Cummings School of Veterinary Medicine, Tufts The study purpose is to identify conditions associated with natural death of critically‐ill neonatal llamas and alpacas, for which a decision of euthanasia was not reached during hospitalization. The specific aim was to improve targeted diagnostic evaluation and treatment recommendations in neonatal crias, where clinical signs of illness can remain insidious or vague. A retrospective cohort analysis of necropsy and clinical data was performed, including 61 critically‐ill crias admitted to a university hospital for intensive care management under 2 weeks of age. All data were presented descriptively and compared between patients that were euthanized and those which died naturally, using univariate and multivariate analyses (SPSS‐22). In the cohort of 61 non‐surviving crias (57 alpacas, 4 llamas; 32/61 females), none of the measured clinical or laboratory admission parameters differed significantly between crias that were ultimately euthanized (31/61, 50.8%) or died naturally (30/61, 49.2%). Similarly, median duration of hospitalization did not differ between mortality groups. Pulmonary (46/61, 75.4%), hepatic (26/61, 42.6%) and cardiac pathology (20/61, 32.8%) was most commonly observed on necropsy, with a site of infection identified in 39/61 (63.9%) animals. Multivariate analyses determined that suppurative pneumonia (OR: 4.6, 95% CI: 1.2–17; p = 0.023), prematurity (OR: 6.7, 95% CI: 1.4–32.6; p = 0.019) and older admission age (OR: 1.15 per day increase in admission age, 95% CI: 1.002–1.33; p = 0.046) significantly increased the risk for natural death. These data suggest that advanced diagnostic modalities to facilitate early, etiological identification of infection and pulmonary disease should be explored to enable improved, targeted treatment and illness outcome. ABSTRACT F11 A survey of coccidiosis shedding among small ruminants on St. Kitts and the Appalachian area Jerry Roberson 1; Ninian Cameron‐Blake2 ; Phippa Gibbons1; Jennifer Ketzis2 1College of Veterinary Medicine, Lincoln‐Memorial University; 2School of Veterinary Medicine, Ross University The purpose of these two similar studies was to determine the presence of coccidiosis and contrast the shedding of coccidia in sheep and goats by age group on the island of St. Kitts and in an area of the Appalachia. Small ruminant producers in both locations were contacted in person, by telephone or email until 50 farms in both locations agreed to participate. Convenience fecal samples were collected across age groups on each farm. A modified McMasters test was performed to determine the coccidia per gram. Simple descriptive statistics were applied across four age groups: <six months, six months to <1 year, yearlings and adult (two years and older). The coccidia shedding was highest among those <6 months of age in both regions (Table 1). There was a clear linear trend in decreased shedding as age increased in the Appalachia region. This linear trend was not apparent for small ruminants of St. Kitts. Although some farms utilized coccidiostats, the same linear trend can still be noted. Overall, coccidia shedding on St. Kitts was lower across all species and age groups when compared to the Appalachia region. Because shedding of coccidia decreases substantially from young to old, it appears that a natural immunity develops by adulthood. Coccidiosis control via coccidiostats was not an option on St. Kitts but may be of value in the Appalachia region in young stock but of little value in adults. Table 1. Average coccidia shedding (coccidia per gram) by small ruminant species, location, coccidiostat usage and age group Category <6 months 6 months–<1 year Yearling Adult (>2 years) Appalachia (AP) 5319 2610 1278 281 St. Kitts (SK) 1722 547 303 458 AP ovine 4128 2581 585 188 SK ovine 1433 676 253 428 AP caprine 8847 2708 2292 404 SK caprine 2525 380 378 516 AP coccidiostats 4639 1525 498 299 AP no coccidiostat 8492 4632 2660 280   ABSTRACT F12 Preliminary investigation of xenotransfusion as a therapeutic modality for anemia in goats Joe Smith 1; Austin Viall2; Ryan Breuer3; Paul Plummer2; Amanda Kreuder2; Rebecca Walton2 1College of Veterinary Medicine, Iowa State University; 2ISU; 3University of Wisconsin Treatment of anemia is a common and challenging clinical condition to treat in goats. Despite being a common sequelae of gastrointestinal parasite infection, some veterinary clinics do not have access to caprine whole blood or packed red blood cells. Xenotransfusion is the administration of blood or blood products from one species to another, and is used successfully in small animal emergency situations. Since cattle are more readily available in most teaching hospitals, and can donate larger volumes of blood, the objective of this preliminary study was to evaluate the suitability of donor bovine blood for caprine recipients. This study was divided into 2 phases. For the first phase blood samples were collected under informed consent from 15 bovine and 15 caprine patients. For compatibility evaluation of each combination, the plasma in the centrifuged tube was for major and minor cross matching. For the second phase two goats were then transfused with bovine whole blood and monitored for reactions. Transfused blood cell kinetics were subsequently evaluated. Both goats were euthanized 14 days post transfusion and necropsied. The majority (11/15) of cross matches were compatible between caprine recipients and bovine donors. The live goat transfusions were well tolerated, although an anaphylactic event was observed in 1 goat. No abnormal changes were noted on postmortem examination. Transfused cells were easily recognizable on blood film analysis 5 days post transfusion. Xenotransfusion with bovine whole blood may provide a therapeutic modality for emergency treatment of goats with anemia. ABSTRACT F13 Validation of a predictive model for downer cows presented to a hospital Alexandra Gariépy 1; Maria Puerto Parada1; Juan Carlos Arango‐Sabogal1 ; Marie‐Ève Bilodeau2; André Desrochers1; David Francoz3; Sylvain Nichols1; Gilles Fecteau1 1Faculté de Médecine Vétérinaire, Université de Montréal; 2Hôpital Vétérinaire Victoria; 3Université de Montréal Establishing an early prognosis would help reducing unnecessary treatments on downer cows with a low chance of survival. In a previous study, a multivariable logistic regression model used data from 1471 down cows presented to the Centre Hospitalier Universitaire Vétérinaire to predict the outcome. Variables included were: age, days of recumbency, PCV (%), heart rate, endotoxemia, AST (U/L), creatinine (umol/L), phosphate (mmol/L) and total CO2 (mmol/L). This study objective was to assess the predictive ability of the model on a new series of downer cows treated at the same referral hospital. The study population included all recumbent dairy cattle older than 15 months presented between 2017 and 2019 (n = 137 cases). Information regarding lactation status, hospitalization (outcome, diagnosis) and blood analysis results (CBC, biochemistry) were obtained. The sensitivity and specificity of the model were computed at various probability threshold. For all predictors, the mean and 95%CI (exact or Poisson when required) were estimated. The study population was similar to the previous population except for the following variables that had a statistical difference of the mean: days of recumbency, PCV, AST, creatinine and total CO2. The overall survival was 61%: survival (n = 83) and non‐survival (n = 54). Model sensitivity was 89%, specificity 46% and positive and negative predictive values 73% and 71% respectively, using the optimal probability cut‐off point for the model (50%). The model appears to be an interesting tool, if combined with a complete physical examination to rule out fatal condition. Study limitations include possible selection bias. ABSTRACT F14 Clinical safety data for the use of pantoprazole in hospitalized cattle: A retrospective study Joe Smith 1; Amanda Kreuder2; Austin Kosusnik2; Jonathan Mochel2 1College of Veterinary Medicine, Iowa State University; 2Iowa State University In human patients, multiple adverse effects have been reported from the use of pantoprazole including hematologic and electrolyte abnormalities, as well as anaphylaxis and edema. However, currently no data exists regarding these adverse effects after administration of pantoprazole in cattle. To evaluate the clinical safety of pantoprazole in cattle, medical records of all cattle administered pantoprazole at the Food Animal and Camelid Hospital of Iowa State University over an approximately five year period were retrospectively analyzed for adverse effects. Records were scrutinized for animals with CBC and/or blood chemistry data available immediately before and after administration of pantoprazole and analyzed for percent change in observed values between the testing timepoints. Paired data were then evaluated by paired T tests or Wilcoxon testing. Forty‐three eligible patients were identified. Pantoprazole was administered intravenously (1 mg/kg) or subcutaneously (2 mg/kg). Mild hypomagnesemia was observed post‐pantoprazole administration in ten cattle (<2.1 mg/dL); however, no significant changes were noted when compared to baseline (p = 0.7241). Significant changes were noted in markers of hepatic (p = 0.0059) and renal function (p = 0.0293), however, these were not clinically significant (decreased BUN, AST). Anaphylaxis post‐pantoprazole administration was not observed, however seven cattle displayed edema after dosing. Clinicians should be aware of the potential for adverse events in hospitalized cattle being administered pantoprazole and monitor patients accordingly. While these preliminary retrospective results indicate that pantoprazole may be a safe adjunctive therapy in cattle, additional studies are warranted to further determine the safety and toxicity for cattle. ABSTRACT F15 Change of antimicrobial prescriptions in calves in Switzerland after the launch of antimicrobial use guidelines Alina Hubbuch 1; Ruth Peter1; Barbara Willi2; Sonja Hartnack3; Cedric Muentener1; Hanspeter Naegeli1; Christian Gerspach4 1Institute of Veterinary Pharmacology and Toxicology, Vetsuisse Faculty, University of Zurich; 2Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, University of Zurich; 3Section of Epidemiology, Vetsuisse Faculty, University of Zurich; 4Clinic for Ruminants, Department for Farm Animals, Vetsuisse Faculty, University of Zurich The increasing threat of antimicrobial resistance promotes the need for antibiotic stewardship programs to foster responsible antimicrobial use. Therefore, guidelines for prudent antimicrobial use supported by an online antimicrobial stewardship tool (AntibioticScout.ch) were introduced in Switzerland in December 2016. The objective of the present study was to evaluate antimicrobial prescriptions for Swiss calves before (2016) and after (2018) the launch of these guidelines. To that end, cases of calves with pneumonia, diarrhea and otitis from a university hospital and eight private practices in Switzerland were included. Data on anamnesis, clinical findings, diagnostic work‐up and antimicrobial treatment were collected. Type and percentages [95% CI] of antimicrobial prescriptions were compared between 2016 and 2018. Of the total number of calves, 88.2% [85.4–90.6] in 2016 (n = 625) and 88.4% [85.7–90.7] in 2018 (n = 655) were treated with antibiotics. The use of highest priority critically important antimicrobials (HPCIAs) decreased from 52.7% [48.6–56.9] in 2016 to 38.0% [34.2–41.9] in 2018; this decrease was found at the university hospital and in private practice and in cases with pneumonia and diarrhea. Particularly the use of fluoroquinolones decreased (2016: 43.1% [39.2–47.2]; 2018: 31.1% [27.6–34.8]). Overall, the number of first line treatments increased from 12.8% [10.4–15.6] in 2016 to 20.2% [17.3–23.4] in 2018. In cases with pneumonia, first line treatments increased (2016: 15.3% [11.6–19.9]; 2018: 26.5% [21.8–31.9]) and third line treatments decreased (2016: 43.5% [38.0–49.3]; 2018: 27.9% [23.1–33.3]); this was seen in cases treated at the university hospital, whereas in private practice only a decrease of third line treatments was observed. In cases with diarrhea, more second line at the expense of unjustified antimicrobials were prescribed at the university hospital in 2018. Antimicrobial treatment of calves with otitis did not change from 2016 to 2018. After the introduction of AntibioticScout.ch, more prudent use was observed in the treatment of calves with pneumonia and diarrhea as less HPCIAs, especially fluoroquinolones, and more first line treatments were prescribed. However, the overall frequency of antimicrobial treatment did not change and the use of HPCIAs was still common in 2018. Therefore, further antimicrobial stewardship activities are necessary. ABSTRACT F16 Effect of age and pregnancy status on pharmacokinetics of flunixin in dairy does Joe Smith 1; Tara Marmulak2; Joan Rowe3; Lisa Tell3 1College of Veterinary Medicine, Iowa State University; 2CSU; 3UC Davis The objective of this study was to investigate the effect of age and reproductive status on the pharmacokinetics of flunixin meglumine when administered by intravenous and subcutaneous routes to dairy goats The animals were 8 pregnant dairy does aged 3.75 ± 3.33 years (range: 1–9 years) and 20 nulliparous dairy does aged 0.71 ± 0.04 years (range: 0.66–0.79 years). Does were given flunixin meglumine via intravenous (1.1 mg/kg) and subcutaneous (1.1 mg/kg) routes. Blood samples for quantifying flunixin and 5‐hydroxy flunixin were collected prior to dosing and at predetermined time points. Plasma flunixin and 5‐hydroxy flunixin concentrations were quantified using liquid chromatography and mass spectroscopy. Pharmacokinetic parameters were estimated using noncompartmental methods. When comparing young does to older pregnant does there was an effect of age and reproductive status on pharmacokinetic parameters after intravenous administration for clearance (increased, p = 0.0019); area under the curve (decreased, p = 0.0001); mean residence time (decreased, p = 0.0001); and volume of distribution (increased, p = 0.0238). There were significant differences in time to maximum concentration (decreased, p = 0.0179); clearance (Cl/F) (increased, p = 0.0071); area under the curve (decreased, p = 0.0002); and mean residence time (decreased, p = 0.0012) when comparing the younger to older doe groups after subcutaneous dosing. No significant differences were noted for bioavailability between the groups (p = 0.6780) Age and reproductive status influence the pharmacokinetics of flunixin after intravenous and subcutaneous administration to dairy does.