Relationships between growth-related traits with carcass and meat quality traits in Spanish Assaf suckling lambs

Abstract

Suckling lamb meat is a relevant product in Mediterranean European dairy sheep farms, and the dairy breed Spanish Assaf is widely extended through the Iberian Peninsula. Knowledge of the influence of birth body weight (bBW) and growth rate on suckling lamb carcass and meat quality is scarce, but useful for breeding optimisation and product homogeneity. In turn, these growth-related traits of lambs might be affected by dietary restrictions of their dams. In this study, 34 male Assaf suckling lambs born from two groups of ewes that had been fed diets with different protein levels when they were prepubertal female lambs (17 lambs per group) were analysed. After birth, the suckling lambs were fed ad libitum on milk replacer until their sacrifice (10–12.5 kg live body weight). The quality traits evaluated in carcasses and meat were carcass compactness, fatness and jointing, meat composition, colour, texture and oxidative stability, and fatty acid profile. The dam group did not show significant effects on lamb growth characteristics or carcass and meat quality traits. The bBW factor showed a negative effect on leg subcutaneous fatness and a positive effect on the forequarter and shoulder percentages of the carcass. The bBW also resulted in increased moisture, lipid oxidation stability, and n-3 FA content (lowering the n-6/n-3 ratio) in the meat. Suckling lambs showing very low average daily gain (ADG) tended to present low carcass quality, i.e., higher bone percentage in the loin and low percentages of muscle or fat compared to those showing high ADG. Further studies are needed to confirm and explain the mechanisms of the significant effects reported here for bBW and ADG on the affected quality traits.