Lamb production from Merino ewes mated to Merino or Damara rams

Abstract

Damara sheep have recently been imported to Australia and are being crossed with Merino ewes as a diversification from wool to fat tail sheep production for live sheep export or meat markets. A comparison was made of the lamb outputs from Merino ewes mated to 2 Merino rams and 2 Damara fat tail rams. There were more multiple litters produced in the matings with the Damara rams than from the Merino rams (P = 0.01). The 5-month weights of the crossbred lamb groups (36.3 and 38.9 kg) were higher (P<0.05) than the Merino groups (33.4 and 32.3 kg). Ram lambs were slaughtered at 7 months of age and the carcasses dissected into 'trim lamb' lean portions, fat trims, bone and other oddments. Dressing percentage at slaughter of the crossbred lambs was 3–4% higher (P<0.001), reflecting lower wool production, than the Merino lambs. After adjustment for chilled carcass weight, there were no differences (P>0.05) between rams for the total amount of lean meat. However, the crossbred groups had more external carcass fat (2.59 and 2.64 kg) than the Merino groups (2.14 and 2.15 kg) and, in addition, had fat tail weights of 0.52 and 0.36 kg.