Bayesian estimation of (co)variance components for growth traits in tabapuã cattle

Abstract

Among the features of interest to the animal breeding, that can be measured repeatedly throughout an individual's life, are among other, growth characteristics, which are characteristic features called longitudinal or repeated. It was used 8193 Tabapuã breed records of animal weight raised in 25 farms distributed in the states of Bahia, Alagoas, Sergipe, Minas Gerais and São Paulo and born between the years of 1975 and 2001. Aiming to estimate the (co) variance and genetic parameters for weights at 120 (W120), 365 (W365), 450 (W450) e 550 (W550) days old. Variance components were estimated in a Bayesian context considering a multi-trait animal model with fixed effects for contemporary groups and ages of the mother and the animal. The random effects were considered direct genetic and maternal and maternal permanent environment and error. The effects mothers were included in the model only for W120 and W365. The direct heritability were 0.31, 0.38, 0.33 and 0.29 for W120, W365, W450 and W550, respectively. The fractions of genetic and maternal permanent environment effects on phenotypic variances were 0.06 and 0.01, 0.03 and 0.01 for W120 and W365.