Abstract

Three hundred Romney, Coopworth and Perendale wether lambs reared at the Whatawhata Hill Country Research Station were shorn in either December and April, February and April or only in April before slaughter in May and either well or poorly fed between December and May. Shearing did not affect carcass weight. GR fat depth or export fatness grade. Lambs shorn in December grew most clean wool. Well-fed lambs had a heavier, fatter carcass with more graded P. There was no interaction between shearing treatment and level of feeding. The trial was repeated on 11 commercial hill country farms in the northern half of the North Island using 150 lambs/farm. On 1 farm, where average growth rate exceeded 200 g/d, there was a positive effect on carcass weight from shearing lambs twice before slaughter. On all other farms (growth rates less than 150 g/d) there was no effect (9 farms) or a negative effect (1 farm) on carcass weight from shearing lambs at weaning. Export fatness grade was unaffected by shearing treatment. Wool production was unaffected by shearing treatment for 6 farms, greatest for 2 farms when shorn in December and April and greatest for 1 farm when shorn in February and April. Total net returns from meat and wool for the farm with the fastest growth rate were unaffected by shearing treatment. Total net returns for all other farms were greatest for the group shorn once prior to slaughter. Seventy four wether lambs and 105 ewe lambs were shorn either 3 weeks, 24 hours, or left unshorn before slaughter. Shearing treatment did not affect carcass weight, GR fat depth, export fatness grade or muscle pH.

JA, Metherell

Proceedings of the New Zealand Society of Animal Production, Volume 44, , 37-40, 1984