Survey observations on the reproductive performance of both romney stud and commercial flocks throughout new zealand

Abstract

Abstract The results of a survey conducted during 1962–67, which examined the reproductive performance of commercial pure-bred Romney flocks in five geographical areas throughout New Zealand, are given. Within each area, flocks were grouped into one of four property-type classifications: unimproved hill, improved hill, rolling, hill, and intensive flat land. Overall, the reproductive performance of approximately 1 1/2 million ewes was examined. Significant between-area differences were demonstrated in the age structure of flocks, the time and duration of mating, and the percentages of barren ewes, ewes lambing, and ewes which lost all their lambs. Significant linear increases in lamb tailing and weaning percentages were shown from north to south. There were highly significant interactions between areas and property types in the time of mating and the percentages of lambs tailed and weaned. Significant between-year differences were demonstrated in the age structure and mean size of flocks and in lamb tailing and weaning percentages, which increased linearly from 1962–65 inclusive.