Slaughter performance and carcass and meat quality of Bergamasca light lambs according to slaughter age

This study was designed to evaluate the effects of slaughter age (40 vs. 60 days) on slaughter performance, carcass and meat quality, and fatty acid composition of intramuscular and subcutaneous fat of Bergamasca lambs reared according to the traditional transhumant system in central Italy. Lambs slaughtered at 60 days of age had higher carcass weight (12.44 vs. 10.36 kg), lower dressing percentage (47.68% vs. 52.16%), and higher proportion of non-carcass components and leg commercial cut (37.82% vs. 35.49%). Furthermore, after 3 and 6 days of storage, the meat of older lambs showed lower drip loss (3.69% vs. 6.16%; 5.73% vs. 9.36%, respectively). Slaughter age did not influence meat pH, cooking loss, or chemical composition while older lambs had meat with higher a* (19.43 vs. 18.91). The fatty acid composition of intramuscular fat was not affected by slaughter age, except for C:13 and C:14 fatty acids, which were higher in older lambs. Subcutaneous fat of lambs slaughtered at 40 days of age showed a better fatty acid profile, as lower saturated fatty acids (52.46% vs. 55.68%) and higher mono- and polyunsaturated fatty acids (34.06% vs. 30.16%, 6.46% vs. 5.79%, respectively), and n-6 and n-3 polyunsaturated fatty acids. Furthermore, subcutaneous fat of lambs slaughtered at 40 days of age had better polyunsaturated/saturated fatty acid ratio (0.12 vs. 0.11) and hypocholesterolemic/hypercholesterolemic ratio (1.42 vs. 1.03), and lower atherogenic index (1.32 vs. 1.82) and thrombogenic index (1.98 vs. 2.35). For light lamb production using the traditional rearing systems, slightly heavier lambs can be produced without worsening chemical composition and cooking loss and fatty acid composition of the longissimus lomborum muscle. However, lambs slaughtered at 60 days of age had lower dressing percentages and higher SFA amount of the subcutaneous fat than lambs slaughtered at 40 days.