Tenderness Variation in two Bovine Muscles

Abstract

The longissimus dorsi and semitendinosus muscles from carcasses grading Good to Choice were analyzed for physical and chemical variation. Seventeen-month-old Hereford heifers of similar breeding were used. Even though treatment of the heifers from birth to slaughter was similar, variations in tenderness, chemical composition, pH, and cooking loss were evident. The mean shear force for the longissimus dorsi muscle was 17.4 lb. while the semitendinosus required 20.4 lb. force. The greatest resistance to shear in the longissimus dorsi was at the 13th thoracic vertebra. It is evident from these data that the longissimus dorsi muscle has varied shear value depending on the location of sampling. Measures of tenderness at the posterior portion of the longissimus dorsi may be useful in studies which are planned to show animal variation. The semitendinosus muscle appeared to be more uniform in its tenderness than the longissimus dorsi muscle. Consequently, this muscle may be more suitable for studies designed to demonstrate tenderness differences resulting from treatment, for example, freezing. The tenderness variation accounted for by carcass difference in the longissimus dorsi was large. Variation due to sample location, while exerting less influence than the carcass, was significantly different for percent fat, pH, and moisture. The shear force was less variable when sample location was the selected variable although the difference was not significant. Copyright © 1964. American Society of Animal Science . Copyright 1964 by American Society of Animal Science