Beef carcase characteristics that may be of value in selecting for genetic merit

Commercially important carcase characteristics that may be used for the genetic improvement of Australia's beef cattle were evaluated using, predominantly, published data. Conclusions are based on the relationship of carcase measurements to the anatomical and commercial dissection products of 690 sides of beef and on other Australian and overseas work. Many measurements used as the basis for genetic selection are cost-effective but unlikely to lead to significant genetic gain. Some of the cost-effective measurements chosen will confound and impede genetic change. The commonly used saleable beef yield varies so widely in composition because of fat content that it is unlikely to be a reliable measurement for genetic purposes. Because of its homogeneous composition, estimated lean meat yield (muscle), which is seldom used for descriptive purposes in the cattle and beef industries, is a much more reliable measure of genetic merit than saleable beef yield. Eye muscle area, used alone or in conjunction with carcase weight and fat thickness, is of limited value in quantifying muscle, particularly in carcases of similar size. Butt profile, which is strongly influenced by subcutaneous fat deposits, is often negatively associated with beef yield. Subjective muscle score, assessed by competent muscle scorers, when used alone or together with carcase weight and fat thickness did not improve the estimation of saleable beef yield. A second subcutaneous fat thickness measurement generally does not improve upon the accuracy of a single fat thickness measurement for quantifying carcase muscle. Specific breed equations give significant improvements in the prediction of carcase muscle and should be used where possible. For meat quality characteristics, visual marbling score is so poorly correlated with actual marbling fat as to be of no practical value for genetic improvement. Tenderness measurements, because of their low variation between breeds and their susceptibility to slaughter and chilling stresses cannot be used for genetic selection