Meta-analysis of the comparison of the metabolic and contractile characteristics of two bovine muscles: Longissimus thoracis and semitendinosus

This study used the BIF-Beef data warehouse to determine whether semitendinosus (ST) was a muscle with a faster contraction speed and more glycolytic than longissimus thoracis (LT), regardless of the sex and breed of animals. With more than 500 animals from 7 breeds, we confirmed that LT was more oxidative than ST in males and females, but not in steers, and in all the breeds studied except Montbéliard. The LT had more slow oxidative (SO) and fewer fast oxido-glycolytic (FOG) and fast-glycolytic (FG) muscle fibres than the ST muscle, regardless of sex, in all breeds except Montbéliard and Holstein. SO proportion and the oxidative activity were negatively correlated to FG proportion and to the glycolytic activity. Similarly, FOG proportion was positively correlated to the glycolytic activity and negatively to FG proportion. However, these relationships are not consistent across sexes and breeds. In conclusion, differences in muscle types may be affected by sex or breed but to a moderate extent only.