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Abstract: The objective of this work was to evaluate the allometric growth, the correlation of the cuts with the half carcasses, and the muscularity index of the leg of ½ Dorper + ½ Santa Inês lambs slaughtered with 2.0, 3.0, and 4.0 mm of subcutaneous fat thickness (SFT). Twenty-four non-castrated male lambs were used, being distributed according to their weight into three collective pens. Slaughtering occurred as the lambs reached the SFT predetermined by ultrasound. The half carcasses were weighed, dissected, and separated into five cuts: neck, shoulders, rib, loin, and leg. These cuts were dissected and weighed into muscle, subcutaneous fat, intermuscular fat, and bone. In the shoulders, lambs with 2.0 and 4.0 mm SFT showed early growth. In the rib, this early precocity was observed in lambs with 4.0 mm SFT. The leg showed isogonic growth in lambs with 3.0 and 4.0 mm SFT and was the cut that best correlated with the half carcass, regardless of the SFT. The slaughter of ½ Dorper + ½ Santa Inês lambs with 4.0 mm of subcutaneous fat allows obtaining a better allometric growth of the shoulder, rib, and leg cuts, as well as a better leg muscularity index.

The objective of this work was to evaluate the effect of slaughter body weight on the quantitative characteristics of carcasses and the yield of commercial cuts of young Nellore bulls. Twenty-four non-castrated, 11-month-old, feedlot-fed Nellore bulls were distributed in a completely randomized design, in three treatments: 350 kg, 400 kg or 450 kg of body weight at slaughter (SBW). Slaughter was performed in a commercial slaughterhouse. The data were analyzed by an ANOVA followed by a Tukey test (p ? 0.05). SBW had no relationship with dry matter intake (6.05 kg/day or 75.74 g/kg BW0.75), feed efficiency (22.16) or feed conversion (4.67). Average daily gain was different depending on the SBW. Animal slaughtered at 350 kg had gained 1.17 kg/day, whereas animals slaughtered at 400 and 450 kg had gained 1.49 and 1.47 kg/day, respectively. Cold carcass weight increased with SBW (189.50, 209.33, and 242.39, respectively). Other carcass characteristics, like pH at 48 h (5.75), cold dressing carcass (52.61%), chilling losses (1.79%), fat thickness (5.54 mm), marbling (3.34 points), intramuscular fat (6.68%), longissimus muscle area (63.10 cm2) and sarcomere length (1.60 ?m), were not affected by SBW, but SBW increased cold carcass weight. The treatments had effects on the primary and commercial cut weights. However, the cut yields for the forequarter (39.84%), hindquarter (47.82%) and side-cut (12.34%), and the secondary cuts: chuck (14.38%), hump steak (1.94%), shoulder clod (16.97%), brisket point end (5.56%), neck steak (1.00%), striploin (7.77%), outside flat (5.30%), topside (9.36%), tenderloin (2.16%), flank steak (3.41%), eyeround (2.67%), rump tail (1.20%), rump eye (3.89%), shank (4.44%), knuckle (5.25%) and rump cap (1.40%), were not affected by SBW. SBW did not influence (p > 0.05) the commercial cut compositions for all cuts in the forequarter and hindquarter. Finishing young bulls in a feedlot is a strategy to produce beef with reduced feed costs. After all, the slaughter body weight (350, 400 or 450 kg) influenced the quantitative characteristics of the carcass; however, it did not affect the yield of commercial cuts from young Nellore bulls.