Phenotypic and genetic correlations of fatty acid composition in subcutaneous adipose tissue with carcass merit and meat tenderness traits in Canadian beef cattle

Beef cattle traits can be improved through genetic selection. However, genetic selection on one trait can lead to changes of other traits depending on magnitude and direction (i.e. favorable or unfavorable) of genetic correlations between traits. Therefore, the most effective way to improve beef cattle traits is to select cattle based on an index (i.e. multiple trait selection index), which considers the economic impact of the traits under selection and their correlations. Beef fatty acid composition, carcass and meat quality traits are economically relevant traits. The purpose of this study was to evaluate how genetic selection of fatty acid composition in subcutaneous adipose tissue of beef cattle will lead to changes in carcass merit and meat tenderness traits based on measures of these traits in 1366 finishing steers and heifers. The results showed that genetic correlations between fatty acids, carcass and meat tenderness were low in general. However, moderate to moderately high genetic correlations were detected and some genetic correlations are not favorable, including genetic correlations of omega-6 and omega-3 fatty acid ratio with overall tenderness (genetic correlation = 0.41) and total conjugated linoceic acids (CLA) with hot carcass weight (genetic correlation = -0.34). These correlations suggest that genetic selection for a lower or healthier omega-6 and omega-3 fatty acid ratio will reduce overall tenderness of beef while genetic selection for a higher or healthier CLA content will compromise hot carcass weight. Due to these unfavorable correlations, multiple trait economic indexes are recommended when genetic improvement on fatty acid composition, carcass merit and meat tenderness traits is considered simultaneously in the breeding program.