Performance, carcass characteristics and meat quality of Timahdite-breed lambs finished on pasture or on hay and concentrate

Two experiments in two consecutive years were carried out in the Middle Atlas Mountains of Morocco to evaluate the effect of pasture or hay and concentrate feeding on performance and quality of meat. It involved 18 (Experiment 1) and 39 (Experiment 2) Timahdite-bre ed lambs fattened for 3 months to reach a slaughter weight of about 25 kg (Experiment 1) and 40 kg (Experiment 2). After weaning at about 6 months of age, the lambs were divided in each experiment into three groups. The first group of lambs was fattened on pasture (PP), the second group was kept on a drylot and received hay and a commercial fattening concentrate (CC) and the third was fattened on pasture and received half of the drylot group ration (PC). In Experiment 2, in order to avoid effects of growth rate on meat quality, amount of concentrate and hay was monitored to ensure similar growth rates between the 3 groups. Six lambs from each group were slaughtered to study carcass and meat quality. Carcass assessment was based on linear dimensions and meat quality measurements were made on semi-membranous muscle taken from Experiment 1 lambs. Average daily gain was not affected (P > 0.05) by diet in Experiment 2 (186, 203 and 189 g/d for PP, PC and CC groups respectively), while it decreased with increasing pasture in the diet in Experiment 1. Dr ylot lambs displayed better carcass dressing, and less digestive tract development than those fed on pasture. The other carcass characteristics were not significantly affected by diet. Meat from pasture-fed lambs was considered more favourable for human health because of higher poly-unsaturated fatty acid percentages, higher n-3 fatty acids, and lower n-6/n-3 ratio.