Using ultrasound to predict fat deposition in growing lambs of different South African sheep breed types

Subcutaneous fat (SF) and Longissimus thoracis et lumborum muscle (LM) depths of growing lambs from six breeds were monitored. Ram ewe Dohne Merino, Dormer, Dorper, Meatmaster, South African Mutton Merino White Dorper reared together under optimal feedlot management conditions subjected to ultrasound scans every fortnight the point when attained 20 kg body weight up until 300 days age. Exponential linear functions fitted describe change in SF depth, using age respectively, while power curve was LM depth. Moderate good fits achieved for models describing increase depth various production groups with (R2 = 0.48–0.72) or 0.53–0.78) as predictor. These curves showed that hair sheep are early maturing relative wool breeds, should thus be slaughtered at lower live weights achieve uniform levels carcass fatness.