The value of ‘fat-corrected’ conformation as an indicator of beef carcass composition within and between breeds

Abstract

Data for 805 carcasses, which were deboned and trimmed of fat to a standard specification, and 500 dissected carcasses from breed comparison trials were used to examine the relationships between conformation and beef carcass composition, when computed overall (ignoring breeds) and within breed. The sample included crosses out of British Friesian, Hereford × British Friesian and Blue-Grey dams by sires of the main traditional British beef breeds and by Charolais, Limousin and Simmental sires. The analysis was carried out within visually assessed fat classes (trimmed carcasses) or at constant subcutaneous fat percentage in carcass (dissected carcasses). Correlations between conformation and carcass composition were moderate to low, conformation rarely accounting for more than 30% of the variation. The overall and pooled within-breed standard deviations of carcass saleable meat percentage (trimmed joints) were 1.83 and 1.45 respectively, and the corresponding correlations with conformation were 0.38 and 0.15. Comparable overall and within-breed parameters for the percentage of trimmed higher-priced cuts were respectively 1.05 and 0.93 (standard deviations) and 0.32 and 0.12 (correlations). Similar results were obtained with the sample of dissected carcasses. The overall results were dependent on the sample of breeds involved, and breed generally provided a more precise prediction of composition than conformation. The results indicate that ‘fat corrected’ conformation is of value in commercial classification schemes particularly where breed cannot be identified. It is, however; less clear whether the relationships between conformation and composition are sufficiently precise to be of value within breed.