Estimating variance components for growth, feed efficiency and carcass merit traits in Angus steers using additive and dominance genomic relationship matrices

Abstract Text: Variance components were estimated in a purebred Angus population of 742 steers using additive and dominance genomic relationship matrices constructed from genotypes of the Illumina BovineSNP50 Beadchip. Traits studied were birth weight (BWT), weaning weight (WWT), feedlot dry matter intake (DMI), average daily gain (ADG), residual feed intake (RFI), hot carcass weight (HCW), lean meat yield (LMY), carcass marbling score (CMAR), rib eye area (REA), and backfat thickness (AFAT). Estimated narrow sense heritability ranged from 0.25 ± 0.08 for ADG to 0.56 ± 0.08 for DMI. Maternal heritability estimates were 0.15 ± 0.05 and 0.17 ± 0.05 for BWT and WWT, respectively. Proportions of phenotypic variances explained by dominance were zero for DMI, RFI, and CMAR, very small for HCW (3%) and REA (5%), low for WWT (10%), LMY (14%) and AFAT (11%), and relatively larger for BWT (24%) and ADG (25%). 

Keywords:

additive

dominance

genomic relationship matrix