Genetic parameter estimates for feed efficiency and dry matter intake and their association with growth and carcass traits in Nellore cattle

This study estimated genetic parameters and (co)variance components for dry matter intake (DMI), average daily gain (ADG), feed conversion rate (FCR), residual feed intake (RFI), residual body weight gain (RWG) and residual intake and body weight gain (RIG) in Nellore cattle. We also estimated the genetic and phenotypic correlations between these traits with growth and carcass traits. We used data on feed efficiency of 1038 Nellore males (Bos indicus), being 147 castrated and 891 young bulls. The animals were progenies of 176 sires and 779 dams, composing a relationship matrix of 3521 animals. The (co)variance components and genetic parameters were estimated by GIBBS2F90 software, using the Bayesian approach. The heritability estimates for DMI, RFI and RIG were 0.40, 0.38 and 0.54, respectively. The genetic correlations between all feed efficiency and carcass traits were low. The traits analyzed showed enough genetic variability and heritability, thus the inclusion of feed efficiency in animal breeding programs of Nellore cattle is feasible. The RIG showed higher heritability and a selection for feed efficiency does not have a negative effect on carcass traits.