Influence of Crossbreeding of Ghezel Ram With Grey Shirazi Ewe on Growth Performance, Feed Efficiency and Carcass Traits of Fattening Lambs

In this investigation, performance, feed efficiency and carcass traits of 48 weaned crossbred Grey Shirazi × Ghezel and purbred Grey Shirazi fattening lambs (mean live weight, 28.5 ± 0.5 kg and age, 115 ± 5 days) were evaluated. Lambs were divided into 4 groups contain the GM group (12 purebred male lambs of Grey Shirazi ewe × Grey Shirazi ram), the GF group (12 purebred female lambs of Grey Shirazi ewe × Grey Shirazi ram), the CM group (12 crossbred male lambs of Grey Shirazi ewe × Ghezel ram) and the CF group (12 crossbred female lambs of Grey Shirazi ewe × Ghezel ram). The dry matter intakes (DMI), average daily gain (ADG) and carcass traits in the lambs were determined. The DMI was greater in CF lambs compared to GF lambs ( P  < 0.001). Feed conversion ratio (FCR) was higher in male lambs comparing to female lambs ( P  = 0.001). The final body weight, ADG, live weight at the slaughtering and hot carcass weight (HCW) were lower in GF lambs compared to another lambs ( P  < 0.001, P  = 0.003). Cold carcass weight (CCW) in CM lambs was higher than in other groups. The Longissimus dorsi (LD) area was higher in crossbreed male lambs ( P  = 0.001). Crossbreeding improved grow performance (final body weight and ADG) in male and female lambs. Carcass trait was improved by crossbreeding especially in male lambs. Sex effect on growth performance and carcass traits was noticeable and male lambs had superior growth.