Abstract

Proportions of ewes having 1 to 4 lambs in 72 local breed flocks with mean litter sizes per ewe ranging from 1.07 to 2.30 were examined, and compared with the proportions recorded in 12 groups of Booroola and 8 groups of Finn type ewes. Below a mean litter size of 1.70, differences in litter size resulted from differences in the proportion of ewes having singles and twins. Mean litter sizes ranging from 1.70 to 2.30 were accompanied by changes in the proportions of ewes having singles and triplets, the proportion of ewes having twins or quadruplets showing no significant change. The proportions recorded in local breed flocks and groups of Finn-type sheep were similar over litter sizes of 1.70 to 2.30. Groups of ewes that carried 1 copy of the Booroola gene had more ewes with 1, 3 and 4 lambs, but fewer ewes with twins, than the local breed flocks.

TW, Knight, DRH Hall, and LD Wilson

Proceedings of the New Zealand Society of Animal Production, Volume 43, , 17-20, 1983