Use of whole barley with a protein supplement to fatten lambs under different management systems and its effect on meat and carcass quality

This study involved 53 Talaverana-breed lambs fattened until reaching a slaughter weight of 28 kg. After weaning at 45 days of age, the lambs were divided into four study groups. The lambs of two of the groups were fattened at pasture, while those of the other two groups were kept on a drylot. One group at pasture and another on the drylot received a commercial fattening concentrate. The other two groups received whole barley with a protein supplement. Drylot lambs displayed better carcass dressing, greater carcass fatness, higher carcass conformation values and a superior refrigerated carcass weight than lambs fattened at pasture. Lambs fattened with concentrate displayed better carcass dressing, higher carcass compactness and less digestive tract development (due to a lower proportion of stomach and digestive content) than those fed barley. The fat colour of lambs fattened at pasture was lighter (greater L*) than that of the drylot lambs, and the lambs fed concentrate exhibited a higher redness index (a*) than those fed barley. The longissimus dorsi (LD) muscle was used to evaluate meat quality. The lambs fattened at pasture displayed a lower lightness value, lower cooking losses and greater pleasantness scores in the sensorial analysis than drylot lambs. The lambs fattened at pasture presented lower values of fatty acids with an odd number of carbon atoms and monounsaturated fatty acids and higher linolenic acid (C18:3) levels than drylot lambs in both the intramuscular fat of the LD muscle and in subcutaneous fat. The lambs fed barley exhibited a higher proportion of fatty acids with an odd number of carbon atoms and lower C18: 3 values than the lambs given the concentrate.