A comparison of Romney and first cross border Leicester-Romney ewes for export lamb production

Abstract

The lifetime performance of first cross Border Leicester—Romney and pure Romney ewes mated to Southdown rams for export lamb production has been studied. In all aspects of lamb production—ewe mortality, lamb losses, barrenness, and twinning rate—the crossbred ewes were superior, the lambs weaned/ewe mated being 139 per cent and 112 per cent. Lamb growth rates and drafting percentage favoured the crossbreds. The carcass quality of the lamb from the crossbred ewes was slightly inferior in terms of conformation but slightly superior in leanness. The crossbred ewe fleeces were 0.6 lb heavier, two units of quality number stronger, and of the same grade as the purebred. Dental attrition was slightly worse in the crossbreds. It is calculated that 9 per cent fewer crossbred ewes could be carried/ac, primarily on account of higher liveweight, 136 lb v. 121 lb, and that the superiority of the crossbred of 25–30 per cent in lamb production and 4–8 per cent in wool production would be reduced on a per-acre basis to a...