Genetic correlations between visual scores and reproductive traits in Nelore cattle using Bayesian inference

Abstract

The aim of this work was to estimate the heritability and the genetic correlations between visual scores and reproductive traits of Nelore cattle. The traits evaluated were: finishing, muscling, and conformation scores at weaning (PD, MD, and CD, respectively) and yearling (PS, MS and CS, respectively); age at the first calving (IPP) and scrotal circumference (PE). The records of 66,244 animals born between 1990 and 2006 were used. The genetic parameters were estimated using bi-trait animal analyses with Bayesian inference. A linear model for IPP and PE and a nonlinear (threshold) model for visual scores were used. The heritability estimates were: CD, 0.19±0.02; PD, 0.23±0.02; MD, 0.20±0.02; CS, 0.26±0.01; PS, 0.33±0.02; MS, 0.32±0.02; IPP, 0.16±0.03; and PE, 0.36±0.02. Genetic correlation estimates between visual scores and IPP were negative, varying from -0.18±0.03 to -0.29±0.02. Positive genetic correlations were obtained between the visual scores and PE, from 0.19±0.01 to 0.31±0.01. Animal selection with the highest visual scores, mainly those taken after the yearling age, allows to improve herd reproductive traits.