Comparison among Ile de France (IF), Gentile di Puglia (GP) and IFxGP (F1, F2, F3) cross-breed lambs. IV. Performances at slaughter.

The research was carried out, for 4 years, on 262 male and female lambs born from single birth of Gentile di Puglia (GP) and Ile de France (IF) ewes and IF for GP (F1, F2 and F3) crosses. Animals were slaughtered at 35 and 56 days of age, in order to quantify the possible effect of breed, birth season, sex, rearing system and age at the slaughter. The most important results show that F2 lambs were characterized by a live net weight higher than IF and a carcass yield higher than GP and F1. F3 lambs showed a higher stabled and net live weight in comparison with F2 lambs and a higher carcass yield than GP. Autumn lambs were characterized by higher performances at the slaughter in comparison with spring lambs. Male animals were characterized by a higher live weight at the slaughter than the females. Artificially reared lambs showed a higher incidence of hide+fleece, intestine and penk, conseguently, the carcass yield was lower than the natural rearing. Lambs showed higher performance if slaughtered at 56 days of age. The length of the small intestine was longer in F1 than in IF and GP. All the linear leasures of the intestine were significantly longer in artificially reared lambs.