What is the impact of the rearing management applied during the heifers' whole life on the toughness of five raw rib muscles in relation with carcass traits?

The aims of this study were, analysing the effects of rearing managements, carcass traits, and muscle type (M. complexus [CP], M. infraspinatus [IF], M. longissimus [LM], M. rhomboideus [RH], and M. serratus ventralis [SV]) on toughness of raw meat; developing prediction models to act on their toughness. According to our results obtained on the data of 77 heifers, the IF raw muscle was the toughest and appeared the most sensitive to a change in the rearing management. The four other raw muscles had a similar toughness within heifers from the same rearing management. The five raw muscles were less tough when the carcass was heavier and had higher dressing percentage and conformation. The 3 models explained about 40% of the variability observed. Our models showed that it is possible to improve the potential tenderness of raw meat, acting on: age of the heifer's mother, growth rate during the growth and fattening periods, slaughter age, carcass weight and temperature 24 h post-mortem.