Genetic correlations between mature body condition, weight, and hip height and early fat-depth traits in Australian Angus cattle

The objective of this study was to estimate genetic correlations between mature cow traits: body condition (MBC), weight (MCW), hip height (MCH), and live animal ultrasound scan and carcass fat depth traits: P8 fat (P8) and rib fat (RIB) in Australian Angus cattle. Genetic parameters were estimated using univariate animal models, and up to four records per cow were used in the analyses for MBC, MCW, and MCH. The heritability estimates for MBC, MCW, and MCH were 0.21 ± 0.01, 0.43 ± 0.01, and 0.55 ± 0.03, respectively. The strongest genetic correlation was observed between the MBC and MCW (0.87 ± 0.01), followed by MCW and MCH (0.83 ± 0.01). Moderate genetic correlations were observed between MBC and ultrasound scan P8 fat (0.35 ± 0.03) and rib fat (0.31 ± 0.03) traits measured on heifers and steers. Genetic correlations between MBC and carcass P8 fat (0.19 ± 0.08) and rib fat (0.30 ± 0.15) were low to moderate. Progress from selection for MBC based on live animal ultrasound scan and carcass fat depth traits measured on young cattle would be slow due to low genetic correlations. Since MBC is adequately heritable, this trait could be used as a direct measure to improve cow condition through selection.