22
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Productive and reproductive performance of heifers fed different levels of urea in the diet Translated title: Desempenho produtivo e reprodutivo de novilhas alimentadas com diferentes níveis de uréia na Dieta

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The objective of the present study was to evaluate the nutrient intake, blood parameters, follicular diameter and performance of pre-puberty crossbred heifers fed isoproteic diets (14.1%CP) containing 0.0; 0.44; 0.88 and 1.32% urea on the total dry matter (DM) of the diet, with a 77:23 roughage:concentrate ratio. Twenty-four 18- month old heifers (Holstein x Zebu), 277.9 kg mean live weight (LW) were used, distributed in four treatments and six replications in a randomized complete design. The following were evaluated: dry matter intake (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), hemicellulose (HEM), plasmatic ureic nitrogen (PUN), plasmatic glucose, plasmatic total cholesterol, follicular diameter and daily weight gain (DWG). No influence of the urea levels in the diet was observed on NDF and HEM intake. A maximum intake was obtained of DM (8.75 kg day-1), CP (0.88 kg day-1), ADF (2.5 kg day-1) and EE (0.17 kg day-1) respectively for the levels 0.7, 0.8, 0.7 and 0.7% urea in total DM. The 0.6%; 0.77% and 0.6% urea levels in diet were the critical points for obtaining maximum response for the PUN (10.96 mg dL-1) and plasmatic glucose(84.97 mg dL-1) concentrations and, for follicular diameter (11.08 mm) on the 40th; 24th and 31st day, respectively. The plasmatic total cholesterol concentration and DWG were not influenced by the urea added to the diet, with averages of 119.39 mg dL-1 and 1.66 kg day-1, respectively. It was concluded that urea can be added up to 1.32% on the total DM of the diet for pre-puberty crossbred heifers.

          Translated abstract

          Com o presente trabalho objetivou-se avaliar o consumo de nutrientes, parâmetros sangüíneos, diâmetro folicular e desempenho de novilhas mestiças pré-púberes alimentadas com dietas isoprotéicas (14,1%PB) contendo 0,0; 0,44; 0,88 e 1,32% de uréia na matéria seca (MS) total, com relação volumoso:concentrado 77:23. Utilizaram-se vinte e quatro novilhas (Holandês x Zebu) com média de 277,9 kg de peso vivo (PV) e 18 meses de idade, distribuídas em quatro tratamentos e seis repetições em delineamento inteiramente casualizado. Foram avaliados consumos de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), extrato etéreo (EE), hemicelulose (HEM), nitrogênio uréico plasmático (NUP), glicose plasmática, colesterol plasmático total, máximo diâmetro folicular e ganho de peso diário (GPD). Não foi observada influencia dos níveis de uréia na dieta sobre os consumos de FDN e HEM. Obteve-se o máximo consumo de MS (8,75 kg dia-1), PB (0,88 kg dia-1), FDA (2,5 kg dia-1) e EE (0,17 kg dia-1) respectivamente para os níveis 0,7; 0,8; 0,7 e 0,7% de uréia na MS total da dieta. Os níveis 0,6%; 0,77% e 0,6% de uréia na dieta foram os pontos críticos para obtenção de resposta máxima para as concentrações de NUP (10,96 mg dL-1) e glicose plasmática (84,97 mg dL-1) e, para o diâmetro folicular (11,08 mm) nos respectivos dias 40º; 24º e 31º. A concentração do colesterol plasmático total e o GPD não foram influenciados pela adição de uréia, com médias de 119,39 mg dL-1 e 1,66 kg dia-1, respectivamente. Conclui-se que a uréia pode ser adicionada até 1,32% na MS total da dieta para novilhas mestiças pré-púberes confinadas.

          Related collections

          Most cited references26

          • Record: found
          • Abstract: not found
          • Article: not found

          Nutrient requirements of beef cattle

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Nutrient requeriment of dairy cattle

              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Effects of nutrition and metabolic status on circulating hormones and ovarian follicle development in cattle.

              Nutrition is a major factor affecting cow reproductive efficiency. Long-term moderate or chronic dietary restriction results in a gradual reduction in dominant follicle (DF) growth rate, maximum diameter and persistence. Animals become anoestrus when they lose on average 22-24% of their initial body weight. There is evidence of significant animal-to-animal variation in the interval from the imposition of dietary restriction to onset of anoestrus and from the recommencement of re-alimentation to resumption of ovulation. In contrast, acute dietary restriction to 40% of maintenance requirements rapidly reduces dominant follicle growth rate and maximum diameter and induces anoestrus in a high proportion (60%) of heifers within 13-15 days of dietary restriction. In lactating dairy and beef cows negative energy balance or reduced dietary intake in the early post-partum period, while not affecting the population of small-to-medium size follicles, adversely affects the size and ovulatory fate of the dominant follicle. Re-alimentation of nutritionally induced anoestrous heifers results in an initial gradual increase in dominant follicle growth rate and maximum diameter, followed by a more accelerated increase in dominant follicle growth rate and maximum diameter as the time of resumption of ovulation approaches. Increased dominant follicle growth rate and maximum diameter are associated with increased peripheral concentrations of IGF-I, pulsatile LH and oestradiol. Direct nutritional effects on ovarian function appear to operate through hepatic rather than follicular regulation of IGF-I, and on systemic concentrations of IGF-I BPs and insulin; cumulatively reducing follicular responsiveness to LH and ultimately shutting down follicular oestradiol production. Indirect nutritional effects are apparently mediated through altering the GnRH pulse generator and in-turn selectively reducing pulsatile LH secretion without any apparent adverse effect on FSH secretory patterns. Endogenous opioid peptides, NPY and glucose appear to play a role in the nutritional regulation of GnRH release and in turn pulsatile LH secretion.
                Bookmark

                Author and article information

                Contributors
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Journal
                rca
                Revista Ciência Agronômica
                Rev. Ciênc. Agron.
                Universidade Federal do Ceará (Fortaleza )
                1806-6690
                December 2010
                : 41
                : 4
                : 677-685
                Affiliations
                [1 ] Universidade Estadual Paulista Brazil
                [2 ] Universidade Federal do Tocantins Brazil
                [3 ] Universidade Federal de Minas Gerais Brazil
                Article
                S1806-66902010000400023
                10.1590/S1806-66902010000400023
                60d5bca4-e799-4cf3-9ad5-07f1d5b1169b

                http://creativecommons.org/licenses/by/4.0/

                History
                Product

                SciELO Brazil

                Self URI (journal page): http://www.scielo.br/scielo.php?script=sci_serial&pid=1806-6690&lng=en
                Categories
                AGRONOMY

                Horticulture
                Cholesterol,Feedlot,Plasmatic ureic nitrogen,Weight gain,Colesterol,Confinamento,Ganho de peso,Nitrogênio ureico plasmático

                Comments

                Comment on this article