Estimation of co-variance components, genetic parameters and genetic trends of VIAscan carcass traits of New Zealand Romney lambs

Publication date: Available online 9 March 2019Source: Small Ruminant ResearchAuthor(s): Adel H.M.IbrahimAbstractThe aim of this study was to estimate co-variance components, genetic parameters and direct genetic trends of carcass traits of New Zealand Romney lambs assessed by VIAscan technology. Data for VIAscan carcass traits of 3389 lambs that included hot carcass weight (VHW); subcutaneous fat depth near the 12th rib (VGR) and meat yield (expressed as a percentage of VHW in the shoulder (SHY%), loin (LNY%), hind leg (LGY%) and whole carcass (TY%) were analyzed by employing different animal models for univariate and multivariate analysis using restricted maximum likelihood (REML) procedures with ignoring or including maternal effects. Year of birth, parity of ewe and type of birth were included in the model as fixed factors, as well as the linear covariate of age of lamb at drafting was fitted into the model. Based on the most appropriate model, estimates of direct heritability (h2a) ranged from moderate to high for VHW (0.29 ± 0.02), VGR (0.56 ± 0.09), SHY% (0.34 ± 0.07), LNY% (0.37 ± 0.06), LGY% (0.38 ± 0.08) and TY% (0.31 ± 0.02), however, the estimates of maternal heritability (h2m) ranged from low to moderate for VHW (0.10 ± 0.03), VGR (0.38 ± 0.08), SHY% (0.18 ± 0.02), LNY% (0.15 ± 0.04), LGY% (0.19 ± 0.02) and TY% (0.17 ± 0.02). VHW was positively genetically correlated with all VIAscan carcass traits (0.15...
Source: Small Ruminant Research - Category: Zoology Source Type: research