Abordagem bayesiana multivariada para características de crescimento, fertilidade e escores visuais de rebanhos da raça Brangus

Abstract

The objective of this work was to estimate genetic parameters, and genetic and phenotypic trends of a Brangus breed population. Weight, scrotal circumference, and visual scores of conformation, precocity, musculature, and navel, adjusted to 550 days of age, were evaluated from records of 6,789 animals sired by 288 bulls and 5,949 dams, born between 1991 and 2001 in 49 farms located in the Center-West, Southeast, and South regions of Brazil. To estimate parameters, correlations, and genetic trends, a six-trait, linear-threshold animal model was adopted. Direct heritability estimates were 0.39 and 0.27 for weight and scrotal circumference, respectively, and 0.22, 0.20, 0.23, and 0.33 for conformation, precocity, musculature, and navel, indicating considerable additive genetic variation, and that it is possible to obtain genetic gain by selection. Genetic correlations between weight and scrotal circumference with the scores of conformation, precocity, and musculature show the possibility of correlated responses. Genetic trends indicate great contribution of non-genetic sources of variation in the evaluated traits, which leads to the necessity of improving environmental conditions, in order for the animals to fully express their genetic potential.