Comparison of expected progeny difference estimatives by three methodologies in Nellore beef cattle / Comparação de estimativas de diferenças esperadas de progênie por três metodologias em touros da raça Nelore

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The strong competition in beef market imposed an actual trend of searching for quality in beef production systems, trying to attend the consumersdemand. Due to the necessity of increasing productivity, animal breeding programs have been utilized to increase cattle efficiency, offering more profitability to the production system. The present study was carried out to contribute to knowledge about siresprogeny variability, using Expected Progeny Difference (EPD) from calves of 359 sires. EPDs were estimated by REML procedures. The prediction od bulls EPDs were performed by software SAS, using 45,014 data of weaning weight (PD), 45,014 of post-weaning weight (PS) and 45,014 of weight gain post-weaning (GP) from Nellore beef cattle, raised in a tropical area of Brazil. Those data were analyzed according with three methods: application of arithmetic mean, harmonic mean of EPD added by trait mean and only harmonic mean. Results suggested that estimation of EPDs using harmonic mean on condition that adjust sires additive genetic value to dispersion form its calvesgenetic values did not make difference to the prediction trough arithmetic mean in the population studied. Due to the implications and importance of alternative methods to adjust bulls EPDs to variability of progeny, further studies are necessary to search for better progenys uniformity.

ASSUNTO(S)

progênie epd progeny bovinos de corte média harmônica beef cattle ceip variabilidade ceip variability harmonic mean dep

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