Some effects of pregnancy in eight-month-old Merino ewes

Abstract

The effect of pregnancy in Merino ewes joined at eight months of age was assessed by comparing their subsequent liveweight, wool production and fertility with similar ewes first joined at 18 months. Of 305 ewes joined at eight months (30 kg average liveweight) only 19 per cent lambed. Pregnancy in these ewes was associated with a short term check to growth which was overcome by the time their second lamb crop was weaned. It was also associated with a 7 per cent reduction in hogget fleece weight, but had no effect on the next year's production. The proportions of ewes pregnant and giving birth to twins following the 18 month joining were independent of whether or not the ewes had lambed previously.