The effect of weight on carcass and meat quality of Serra da Estrela and Merino Branco lambs fattened with dehydrated lucerne

Abstract

Thirty-four ram lambs of the Serra da Estrela (SE) and Merino Branco (MB) breeds were used to evaluate lamb growth performance and the effect of carcass weight on carcass composition and meat quality traits. Five Iambs of each breed were slaughtered after weaning, at 16 kg average live weight (LW), and the remaining were fed ad libitum with dehydrated lucerne and minerals and slaughtered at 25 or 35 kg LW. The left sides of the carcasses were totally dissected. The Longissimus thoracis and Longissimus lunborum muscles were used for meat quality determination. MB lambs grew faster than SE lambs. The muscle/bone ratio was higher for SE lambs (2.84 vs. 2.63) and breed had no effect on meat quality traits, except for water-holding capacity that was higher for MB lambs. Dressing percentage was about 55% at weaning, decreased to about 53% at 25 kg live weight and remained unchanged afterwards. Muscle/bone ratio increased with slaughter weight, ranging from around 2.5 at weaning to 3.0 at 35 kg live weight. As carcass weight increased, muscle pH and water-holding capacity decreased but temperature and intramuscular fat increased. Juiciness scored better for higher carcass weights, however, the overall effect of carcass weight on meat quality traits was minimal, and probably without any commercial impact.