Effects of castrating lambs on growth and body composition

Abstract

Effects of castration on growth, wool production, carcass characteristics, and meat quality in sheep were investigated.The experiment included two flocks (similar in their effect on pre-weaning performance, but representing high and low planes of nutrition after weaning), two years, and two slaughter ages. Rams weighed approximately 5 % more thanwethers at weaning, and 15 % and 23 % more as yearlings on the low- and high planes of nutrition respectively. Differences in favour of rams in terms of skeletal and muscle size and wool production were also greater on the higher plane of nutrition. Carcass weight was approximately 4%, 8% and 19% higher for rams among lambs, low plane and high plane yearlings, respectively. Proportion of carcass weight in the forequarters was 0·5 %, 1·1 % and 2·3 % higher for rams in these three groups. Rams had less kidney fat and the same percentage of the carcass weight in loin and trimmed leg as wethers in all groups.Carcass grade and eating quality as evaluated by a taste panel did not differ between ram and wether lambs. Among the lighter yearling group, meat from the loin of ram carcasses was less tender. Quality was appreciably lower for rams in the heavier yearling group. Meat from ram carcasses had 1 to 2% higher cooking loss than that from wethers.