Abstract

A Poll Dorset flock was mated naturally in spring for 4 years. As lambing date shifted from mid June to mid April overall flock fertility declined but fecundity did not change greatly. Ewes lambing in mid April were under less feed stress during lactation than ewes lambing in late May. Integration of the flock with spring lambing ewes was made easier with a more concentrated lambing pattern in autumn. As lambing date changed from 24 May to 12 April, lamb growth rates in winter declined. However, more than 84% of the lambs reached 30 kg live weight by mid November. High faecal egg counts were recorded in April born lambs before weaning.

MC, Smith, and KG Geenty

Proceedings of the New Zealand Society of Animal Production, Volume 43, , 43-44, 1983