Nutritional stress and pre-implantation embryonic mortality in Merino sheep

Abstract

1. Embryonic mortality and reproductive performance were studied in 150 mature Merino ewes, groups of which were restricted to approximately 15% of their maintenance requirement from days 0to7 (group 1), 6to13 (group 3) and 13to20 (group 4) respectively. Groups 2and5 were controls. Ovulation point counts, returns to service, pregnancy test by laparotomy at day 40 and lambing performance were used to assess and apportion the embryonic loss.