Artículos de revistas
Avaliação de um Sistema de Produção de Gado de Corte. 1. Desempenho Reprodutivo
Fecha
2000-11-01Registro en:
Revista Brasileira de Zootecnia-Brazilian Journal of Animal Science. Vicosa-mg: Revista Brasileira Zootecnia Brazilian Journal Animal Sci, v. 29, n. 6, p. 2209-2215, 2000.
1516-3598
WOS:000176458900008
WOS000176458900008.pdf
Autor
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Universidade Estadual Paulista (Unesp)
Institución
Resumen
Data from 1983 through 1991 on reproductive performance, collected from the Beef Cattle production system at Embrapa Gado do Corte, were analyzed. This system, based on exclusive grazing, presented a pregnancy rate (2-3 years old heifers and cows) of 75.9%. The others observed index were first calving reconception rate, 62.1%, total herd loss rate, 2.2%, and calf loss rate until weaning, 6.0%. The calf loss rate represented 53.7% of the total herd loss rate. For calf loss rate (CLR) data analysis, the used model included the effects of sex (S), calf birth year (ANB), cow birth year (ANV) and the interactions between S x ANB and ANV x ANB. Sex had a significant effect on CLR, with 8.1 and 3.8% for male and female loss rate, respectively. For calving interval analysis, the used model included the following fixed effects: ANV, birth month of cow (MNV), birth cow order when it was a calf (OPV) and the ANV x MNV interaction. The 205-day cow weight and her age at first calving were used as covariables. The calving interval was 463.45 days (15.2 mo), ranging from 388 to 543 days, and it was significantly affected by ANV. It is suggested that more research attention should be directed to the highest loss rate observed for male calves, which represent higher commercial value than females.