Breeding Performance of Dorset Horn Ewes Augmented by Hormonal Treatment

Abstract

Summary: Thirty Dorset Horn ewes were put to the ram four times in two years; four ewes lambed four times to produce 22 lambs, and 21 ewes lambed three times, producing 100 lambs with satisfactory birthweights. The minimum interval from parturition to conception was 32 days and there was no decline in the liveweight of the ewes. Another 37 ewes were run with a teaser ram from 1 January to 1 August 1964 (when it was replaced by a fertile ram) and from 15 April to 31 August 1965 when it was again replaced by a fertile ram. There was a marked decline in oestrual activity in Flock 2 from the middle of March until the middle of July.