Genetic variability of residual variance of production traits in Nellore beef cattle

This study was carried out to provide an exploratory analysis of genetic variability of residual variance of fifteen traits in Nellore beef cattle. The possibility of considering, simultaneously, additive and environmental effects on residual variance was investigated by analyzing log squared residuals associated with each observation according to an animal model. There is evidence of genetic variability for residual variance of most investigated traits, such as birth weight, weight gain from birth to weaning, weight gain from weaning to yearling, scrotal circumference and visual scores (specially in the case of scores for conformation, muscling and sheath). Results suggest that uniformity of some beef cattle traits could be improved by selecting for lower residual variance, when considering large amount of information to predict genetic merit for this criterion. Further studies are needed to confirm the results obtained under the exploratory approach of this work.