Effects of feeding system and nitrogen source on lamb growth, meat characteristics and fatty acid composition

For this study, 28 lambs were allocated to four groups: two groups were raised in stalls and fed a hay-concentrate ration. The two remaining groups were reared on dry pasture and received concentrate in stalls. In each feeding system, two iso-nitrogen concentrates were used, soya bean and soya plus faba bean. At the end of the growth trial (77 days), all lambs were slaughtered. Samples of longissimus dorsi muscle were used for muscle analysis and fatty acid (FA) composition determination. Average daily gain (134g) was similar for all treatments. Stall lambs deposited significantly (p<0.001) more fat per day (13 vs 5g) and slightly more muscle (41 vs 35g) than pasture grazing ones; the first had more fat tissue (5.2kg) than the later (4.6kg). All these parameters were not influenced by nitrogen source. FA profile and meat characteristics were similar for all dietary treatments. It could be concluded that dry pasture did not affect meat quality but lead to the leaner lambs.