I. Growth and carcass quality

Abstract

Abstract Some aspects of lamb performance and carcass composition were investigated using Suffolk cross (Border Leicester-Romney cross) lambs grown to produce carcasses weighing 20–30 kg. In one experiment wether lambs on pasture were compared with lambs receiving either barley-based pellets or a diet containing high levels of protected polyunsaturated fat. The pasture-fed lambs grew considerably more slowly than lambs in the other two groups. Lambs receiving the protected polyunsaturated fat did not grow as fast as those in the grain-fed group and their carcasses contained more fat and less muscle than those of pasture-fed lambs. The differences in overall fatness between the pasture- and grain-fed groups were difficult to assess because the pasture-fed lambs had significantly more fat in some depots (omental, kidney and pelvic, intramuscular), but significantly less in the subcutaneous depot. A second experiment comparing ram and wether lambs on pasture showed inconsistent growth advantages for the rams...