Use of concentrate or pasture for fattening lambs and its effect on carcass and meat quality

Two production systems, pasture and sheepfold based on lambs fed concentrates ad libitum was evaluated for carcass and meat quality of lambs slaughtered at body weights of 24 and 28 kg. There was no effect of production system on growth rate of lambs. In sheepfold, commercial carcass dressing values of slaughter lambs were heavier than in those raised at pasture with more dorsal fat thickness (1.6 nun vs. 1.1 mm), kidney knob and channel fat (1.6% vs. 1.2%) and a greater percentage of leg fat (8.5% vs. 6.6%). Lambs at heavier weights had more fat. Meat quality, pH, water-holding capacity and collagen content parameters were not affected by the production systems. The color of the longissimus dorsi muscle was somewhat darker in lambs fattened at pasture, but no color differences were seen in the rectus abdominis muscle. In both subcutaneous and intramuscular fat of the two cuts studied (leg and loin), sheepfold lambs presented a lower percentage of stearic acid (C18:0) and a higher proportion of palmitic (C16:0) and linoleic (C18:2) acids, and thus a lower percentage of SFA and a higher one of TUFA, while a better (n - 6)/(n - 3) ratio was observed in lambs raised at pasture. Lambs at heavier weights displayed a lower percentage of PUFA and PUFA/SFA ratio in the intramuscular fat of the longissimus dorsi muscle and higher levels of oleic (C18:1) and palmitic (C16:0) fatty acids and a lower one of myristic acid (C14:0) in both depots. (C) 2002 Elsevier Science B.V. All rights reserved.