Genetic association between residual feed intake and carcass traits in a herd of Nellore beef cattle.

• Heritabilities for carcass traits of beef cattle. • Breeding values of carcass traits according to residual feed intake. • Genetic trend of carcass traits in relation to different residual feed intake groups. Our objective was to verify if genetic differences (i.e., additive genetic variation) among animals classified in different residual feed intake adjusted for fat (RFI fat) groups occur, and if selecting for RFI fat impacts carcass traits. Ribeye area, backfat thickness, rump cap (' picanha ' in Brazilian Portuguese) fat thickness, subcutaneous fat thickness, and marbling score were evaluated in relation to the high, medium and low RFI fat groups. Tri-trait analyses were performed using the animal model. The estimated values for heritability were high and no difference was found between the obtained values according to the RFI fat groups, for any of the carcass traits evaluated. These results demonstrate that all traits evaluated in this study have the potential for genetic improvement, regardless of RFI fat classification. The genetic improvement capacity of the herd was confirmed by the genetic trends performed using the breeding value of each RFI fat group, and independently of the group a bull belongs. Therefore, regardless of whether the animals are more or less efficient in terms of RFI fat , it is possible to practice selection for RFI fat in conjunction with carcass traits. [ABSTRACT FROM AUTHOR]