Nutrition and embryo survival in the ewe

T.N. Edey

University of New England, Armidale, Australia

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Proceedings of the New Zealand Society of Animal Production. 1976, 36: 231-239

Results published in the past decade permit reasonably accurate definition of the effects on embryo survival of various nutritional regimes. Severe undernutrition lasting 1 to 3 weeks during the first month of pregnancy often causes measurable loss of embryos. The induced loss rarely exceeds 15%, and is usually higher in twin than in single ovulators. In some experiments increased duration of undernutrition, and in others low ewe body weights have been associated with higher embryonic loss. Age of ewe appears relatively unimportant. The few studies extending into the second 21 days of pregnancy indicate that by this time embryos are more resistant to undernutrition. High plans of nutrition (eg. 200% maintenance) in the pre-implantation period can also cause increased embryonic loss. Little progress has been made in defining the physiological basis of nutritional effects on embryo survival. Progesterone insufficiency has been excluded as a likely cause, and the necessary biochemical studies of the endometrium have been slow to develop in any species, but are now gaining momentum.

Keywords: NZSAPAB;

Last Updated 24-08-2000