A randomized controlled trial of dexamethasone as an adjunctive therapy to propylene glycol for treatment of hyperketonemia in postpartum dairy cattle

The objective of this study was to determine the diagnostic performance of an electronic beta-hydroxybutyrate (BHBA) hand-held meter (Precision Xtra) for use in dairy cattle. Specific objectives were to compare the electronic BHBA meter with serum BHBA concentrations determined photometrically and 2 commonly used chemical cowside tests (Ketostix, Ketolac) and to evaluate accuracy in a field study employing 35 investigators. Of the 196 blood samples collected in experiment 1, 17 (8.7%) contained > or =1,200 micromol of BHBA/L of blood and 10 (5.1%) contained > or =1,400 micromol of BHBA/L of blood. Pearson correlation coefficients were highly significant for all tests. The highest correlation coefficient (0.95) was found between measurements of whole blood BHBA determined with the Precision Xtra test and the serum BHBA concentrations determined photometrically. Correlation coefficients between serum BHBA and BHBA in urine using Precision Xtra and Ketostix, and milk using Ketolac were lower. The Precision Xtra test was both 100% sensitive and specific at > or =1,400 micromol of BHBA/L of whole blood. Using milk and urine, positive and negative predictive values were considerably lower for both chemical tests as well as for the electronic meter. In the second study undertaken with 35 bovine veterinary practices, 926 blood samples were collected. In this study, the Precision Xtra test had sensitivities of 88 and 96% at 1,200 and 1,400 micromol of BHBA/L of whole blood, respectively. Specificities were 96 and 97%, respectively. Level of agreement was lower in the second study employing multiple investigators. Considerable differences in variance occurred among investigators. We conclude that the electronic hand-held BHBA measuring system using whole blood is a useful and practical tool to diagnose subclinical ketosis. Sensitivity and specificity are excellent for a cowside test and higher than 2 commonly used chemical dipsticks (Ketostix and Ketolac).

The relationships between body condition score (BCS) and ketosis, and between BCS and reproductive performance in 732 moderate yielding, dual-purpose cows were studied. The cows were of the breed Norwegian Cattle. Farms with tie-stall barns and a history of high ketosis incidence were chosen for the study. Sixteen assessors visited the farms monthly and the same assessor assigned a BCS to each cow once a month. A BCS of 3.5 or higher at calving was associated with increased risk for ketosis. Cows that subsequently developed ketosis had higher BCS than healthy cows before the disease was diagnosed, and they lost more body condition than did the latter after ketosis had occurred. Summer calving cows and primiparous cows showed the lowest risk of ketosis. A history of ketosis before first service decreased the likelihood of conception to that service. Loss in body condition during the postpartum period was associated with decreased likelihood of conception to first service, prolonged calving to conception intervals and increased number of artificial inseminations per conception. Reproductive performance was not associated with BCS at calving. We concluded that BCS is a useful method of monitoring relations among nutritional management, reproduction, and ketosis in moderate yielding dual-purpose cows.