Effects of castration on growth performance and carcass characteristics of Awassi lambs fed high concentrate diet

Abstract New born male Awassi lambs were randomly assigned to one of two groups: intact (12 lambs) and castrated (12 lambs). After weaning (body weight = 21.0 kg) at the age of 70 days, lambs consumed a high concentrate diet ad libitum for 60 days after which all lambs were sacrificed. The metabolizable energy and CP content of the diet were 2.90 Mcal/kg and 16%, respectively (all in DM basis). Dry matter intake was higher for the castrated lambs as compared to intact animals. Castration had no effect on average daily gain (ADG). Feed to gain ratio for castrated lambs was significantly higher compared to intact lambs. Hot carcass weight, cold carcass weight and dressing percentages were all unaffected by castration. However, kidney fat for castrated lambs was significantly higher compared to the intact lambs. As a percentage of cold carcass weights, intact lambs had greater leg weights compared to the castrated lambs. Fat thickness on the loin area was higher for the castrated lambs. Castrated lambs’ legs had more total and subcutaneous fat compared to the intact lambs. Intact lambs had greater percentages of lean and bone in their legs as compared to the castrated lambs. In conclusion, castration did not affect ADG, cold carcass weight or dressing percentage of Awassi lambs. However, it reduced efficiency of feed utilization, increased subcutaneous fat and decreased carcass leanness. Therefore, due to local consumer preference of leaner carcasses with minimum subcutaneous fat, castration of Awassi lambs to be slaughtered approximately 130 days is not recommended under an intensive feeding system.