Estimates of efficiency of Dorper and Rambouillet lambs.
Feed intake and body weight were recorded on thirty-seven Dorper ram lambs and forty-two Rambouillet ram lambs from weaning to 61kg of body weight to determine feed conversion efficiency. The data were collected over a two year period. Lambs were progeny of 6 unrelated sires per breed. Lambs were approximately 90 days of age and 31kg body weight at the start of the trial. Lambs were fed a commercially prepared, pelleted diet with an average crude protein content of 16% and TDN of 70.5%. Lambs were divided into groups of 10-11 containing both breeds, and fed using FIRE (Feed Intake Recording Equipment, Osborne Industries, Inc, Osborne, KS, USA). Lambs were identified using a unique electronic identification ear tag transponder. Feed intake was recorded electronically and lambs were weighed every two weeks. Data were analyzed using SAS PROC MIXED with a model that included breed and birth type as fixed effects, a random effect for sire, and starting weight as a covariate. In both years of the trial, breed was not found to have a statistically significant effect on ADG or FCE (p>0.05). Post weaning feed efficiency was similar between Dorper and Rambouillet lambs. The Dorpers’ total ADG was 340 g/d; the Rambouillets’ was 342 g/d. The Dorpers’ average FCE was 0.159; the Rambouillets’ was 0.158. Over the post weaning period studied there was no advantage shown by either breed.