Genetic Parameters for Body Conformation Scores and Carcass Traits Measured by Real-Time Ultrasound in Nellore Cattle

Abstract Text: Data from 65,078 Nellore animals were used to estimate genetic parameters for visual scores of conformation (C), finishing precocity (P), and muscling (M), rib eye area (REA), back fat thickness (BFT), and rump fat thickness (RFT) measured by real-time ultrasound. (Co)variance components were estimated using a multi-trait animal model by REML. Heritability estimates were 0.19 (C), 0.21 (P), 0.22 (M), 0.34 (REA), 0.18 (BFT), and 0.39 (RFT). High genetic correlations were observed between visual scores (0.71 to 0.98) indicating that simultaneous inclusion of C, P, and M in a selection index does not seem to be necessary. Genetic correlations between REA with BFT and RFT were -0.02 and -0.17, respectively. Genetic correlation between BFT and RFT was 0.52. Genetic correlations between visual scores and carcass traits ranged from -0.04 to 0.28 indicating that selection for body conformation scores has little effect on carcass traits.

Keywords:

beef cattle
genetic correlation
heritability