The influence of the poll gene and of castration on production characters of male Merino sheep

Abstract

Two drops of lambs were produced in spring 1959 and 1961 by mating poll rams (Pp) to knobbed ewes (pp). At marking time (1-4 wk), a random half of ram lambs of the Pp group and of the pp group were castrated. The rams and wethers were grown together and the following measurements were made-greasy fleece weight, clean scoured yield, clean fleece weight, staple length, crimps per inch, fold score, body weights at weaning and 17 months, and mortality to 17 months. The analyses showed no evidence of significant poll-genotype x sex interactions caused by superiority of Pp rams and pp wethers. It was concluded that segregation of the poll gene had no influence on any of the production characters studied. Rams cut six per cent more clean wool than wethers, but due to the large difference in size, clean wool production per lb body weight favoured wethers by 19 per cent. The ram's wool showed six per cent finer crimping than the wethers' fleece.