Efeitos do fornecimento de dietas contendo nitrogênio não-protéico(NNP) sem prévia adaptação, durante curto espaço de tempo e em diferentes fases do ciclo estral na produção, qualidade e grau de desenvolvimento de embriões de fêmeas bovinas superovuladas / Effect of short term non-protein nitrogen (NPN) feeding to superovulated beef cows without previous adaptation, at different periods of the oestrus cycle on yield, quality and development degree of recovered embryos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

High levels of crude protein (CP) in ruminant diets were associated with detrimental effect on fertility, mainly, due to the rise of plasmatic urea nitrogen (PUN) concentration. The aim of this study was to verify the effects of short term non-protein nitrogen feeding at different periods of the oestrus cycle in superovulated cows without previous adaptation on yield, quality and development degree of recovered embryos. Sixty eight Nelore cows with body condition score of 7.56 and body weight of 557.6 kg were divided in three different groups: control (C), urea before day 0 (UB; urea supply from day -5 to day 0) and urea after day 0 (UA; urea supply from day 0 to day 5). Animals were grazing in Brachiaria brizantha cv. Marandu pasture and received 3.0 kg/animal/day of concentrate during 16 days. Two concentrates were formulated and the total diets (concentrate + estimate forage intake) had 12.0% (control diet) and 14.6% of CP (NPN diet). The difference in CP between diets was the addition of 100g/cow/day of urea. Animals were synchronized, superovulated and inseminated. The embryos were collected seven days (day 7) after insemination (day 0) and quality and development degree were also evaluated. Blood samples were collected on day -5, 0 and 5 for measurement of PUN, glucose, insulin and progesterone. There was significant effect of treatments on average PUN concentration at day -5 (C = 16.18ab, UB = 17.72a and UA = 14.47b mg/dL; P = 0.0007), at day 0 (C = 18.95b, UB = 22.71a and UA = 21.15ab mg/dL; P = 0.0010) and at day 5 (C = 20.93a, UB = 19.08b and UA = 21.51a mg/dL; P = 0.0022). For glucose, insulin and progesterone there was no effect of treatments. It was observed neither effect of urea inclusion nor the moment of urea inclusion in diet on the total number of recovered structures, total number of fertilized structures and total number of viable embryos. However, it was observed effect of the moment of urea inclusion on the rate of fertilized structures in relation to the total number of recovered structures (UB = 75.3 vs. UA = 50.7%) and on the rate of viable embryos in relation to the total number of recovered structures (UB = 73.2 vs. UA = 39.4%). The UA treatment lead to lowest fertilizing oocyte capacity in relation to UB treatment with an approximate reduction of 32.7% on oocytes fertilized proportion over the total recovered structures in this treatment.

ASSUNTO(S)

embryo urea nelore nitrogênio uréico plasmático (nup) plasmatic urea nitrogen (pun) embrião nelore crude protein (cp) proteína bruta (pb) uréia

ACESSO AO ARTIGO

Documentos Relacionados