Produção Nacional
Revisado por pares
Eficiência produtiva em vacas da raça Nelore
2009; INSTITUTO DE ZOOTECNIA IZ/APTA-SAA/SP; Volume: 66; Issue: 2 Linguagem: Inglês
ISSN
1981-4100
AutoresVictor Eduardo Sala, Lúcia Galvão de Albuquerque, Maria Eugênia Zerlotti Mercadante, Arione Augusti Boligon, Sarah Figueiredo Martins Bonilha,
Tópico(s)Genetic and phenotypic traits in livestock
ResumoTo analyze the effects of the measurements of cow productive efficiency and verify if selection for yearling weight (YW) modified the measures of herd productive efficiency, data of Nelore herd, belonging to the Selection Project of Zebu and Caracu Breeds from the Beef Cattle Center APTA (Animal Science Institute - Sertaozinho - Sao Paulo - Brazil), were analyzed. The animals are selected for higher YW (NeS and NeT herds being considered as single herd in this paper) and for average YW (NeC) within contemporary group, since 1980. The ratio of birth weight (RPN), calculated by formula: (calf weight birth/cow weight at calving)*100 as the percentage of calf/cow weight at calving, and the ratio of weaning weight (RPD), calculated using the formula: (weaning weight of the calf/cow weight at weaning)*100 as the percentage of calf/ cow weight at weaning. Model included effects of herd (NeC and NeST), cow birth year and age class, calf gender and herd interaction x year of birth. Statistical analyses by minimum square method (GLM procedure of the SAS software) were used. The selection herds (NeST) showed higher (p<0.01) RPN than the NeC herd - 6.87(0.02)% and 6.59(0.04)% of cow weight, respectively. However, the effect of herd was not significant for RPD - 38.25(0.15)% and 37.96(0.25)% of the cow weight for NeST and NeC, respectively. Effects of cow age class and calf gender was significant for RPN and RPD. The selection for yearling weight did not change the productive efficiency of cows. Young cows are more efficient and produce heavier calf (kg%) in relation to its weight.
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