Suplementação de cordeiros em pastagem tropical na fase de terminação

Abstract

We assessed the effects of concentrate supplementation levels on productive performance, quantitative characteristics of the carcass, morphology and tissue composition of the loin of lamb Dorper x Santa Inês finished on Aruana grass pasture (Panicum maximum cv. Aruana). Used 18 lambs crossbred Dorper x Santa Inês non-castrated with 33 kg distributed at random into three levels of concentrate supplement: 1.25, 2.50 and 3.75% of body weight. The stocking was continuous, getting isoproteic supplements (18% CP) and isoenergetic (75% TDN), provided in the facility. Were slaughtered at 40 kg after fasting solid diet 18 hours. Proceeded to evisceration and measurements, after put in cold storage for 24 hours at 4° C.Later was held the commercial cuts (neck, shoulder, rib discovery, rib, loin, ham and low) in the left half carcass and measurements on muscle Longissimus lumborum. A completely randomized design with three treatments and six replications each, the data were subjected to analysis of variance. The variables of live weight at slaughter (39.62 kg), average daily gain weight (0.272 kg/d), body condition score slaughter (2.70 points), cold carcass weight (18.43 kg) loss by cooling (4.00%), commercial carcass dressing (46.77%), carcass compactness index (0.22 kg/cm) and leg (0.46) were not affected by supplementation levels (P>0.05). The weight of the left half carcass (9.68 kg), the proceeds from the palette (16.77%), neck (9.86%), rib discovery (7.02%), rib (9.72%), loin (10.10%), low (10.87%) and leg (28.61%) were not affected by supplementation levels. The variables loin weight (1.042 kg), loin eye area (12.64 cm2), percentage of muscle tissue (55.48%), adipose (20.37%) and osseous (20.21%), ratio muscle:bone (2.74), ratio of edible portion:bone (3.75) also were not affected by supplementation levels (P>0.05). The higher fat thickness was higher in the group of 3.75% supplementation in relation to the groups supplemented with 1.25% and 2.50% did not differ. The group of 3.75% showed lower thickness greater fat to other treatments, while 2.50% was higher than 1.25% supplementation. Supplementation levels did not affect the variables of productive performance, quantitative characteristics of the carcass, morphology and tissue composition of loin, except for the highest and lowest fat thickness were higher for animals supplemented with 3.75% of body weight.