Carcass composition and meat quality in lambs reared indoors and on pasture

T. Popova, P. Marinova
Abstract. An experiment was carried out with 28 male lambs of Northeastern Bulgarian Fine Wool Breed (NBFWB) and lamb crosses of this breed with Ile de France (NBFWB x IDF) reared indoors and on pasture in the Institute of Animal Science – Kostinbrod. Carcass composition and quality parameters of m. Longissimus dorsi and m. Semimembranosus were studied in the lambs according to their rearing and breed. Most of the lambs reared indoors and on pasture belonged to O and R conformation classes. According to the breed the highest percentage of lambs of NBWFB were in the O class while the carcasses of the crossbred lambs were equally distributed between O and R classes. Lambs reared indoors or on pasture were in classes 2 and 3 according to their degree of fatness. The distribution in both breeds showed that the carcasses of the NBFWB were fatter than those of the cross. Rearing did not affect significantly the thickness of fat in different carcass locations as well as the content of muscle, bone and total fat in the half carcasses. Breed influenced the pelvic fat content which was higher in the lambs of the cross (P<0.05). No significant effect of rearing on the content of meat, bone and fat in the separate parts of the carcass was observed while breed affected significantly the percentage of pelvic fat (P<0.05) and intermuscular fat (P<0.01) in the loin, as both were higher in the lambs of NBFWB x IDF. Rearing influenced the meat colour of m. Longissimus dorsi. It was brighter (P<0.05) in the lambs reared on pasture, compared to the indoors reared lambs. Breed affected significantly the colour of both m. Longissimus dorsi and m. Semimembranosus (P<0.05) and in the lambs of the NBFWB x IDF it was darker. The way of rearing the lambs led to significant differences in the content of myoglobin in m. Longissimus dorsi (P<0.05).