Expected progeny difference as a tool for selection for weaning weight in Brahman cattle

Objective. To determine the Expected Progeny Differences (EPD’s) for the weaning weight of the Brahman cattle as a criterion for selection of future sires. Materials and methods. 552 records of weaning weight (WW) of 33 sires belonging to the farm Mundo Nuevo, San Onofre, Sucre, Colombia, were recorded during 1997 to 2007. The statistical model included the fixed effects: year of birth, season weaning, sex of calf, the number of calving and the random effect of the sire. For the analysis of the environmental factors the method of least squares was used, through of the GLM procedure, contained in the Statistical Analysis System. The heritability was obtained through the variance components using the Varcomp procedure. The EPD’s were calculated using the method Best Linear Unbiased Prediction (BLUP). Results. The average for WW was 238.5 ± 31.6 kg. Sire, sex, number of calving, and year of birth were significant (p?0.05). Estimated heritability was 0.43 ± 0.15. EPD’s ranged between -16.9 and + 17 kg. Accuracies (ACC) ranged from 0.71 at 0.78. Conclusions. The significance of different sources of variation of WW showed no differences with most of the literature consulted. The estimated heritability indicates that genetic progress can be achieved for WW. The results of the EPD’s showed that 52% of the sires showed negative variations for WW.