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The interaction of nutrition and body condition at mating on ovulation rate and early embryo mortality in Scottish Blackface ewes

Published online by Cambridge University Press:  27 March 2009

R. G. Gunn
Affiliation:
Hill Farming Research Organization, Bush Estate, Penicuik, Midlothian, EH26 0PY
J. M. Doney
Affiliation:
Hill Farming Research Organization, Bush Estate, Penicuik, Midlothian, EH26 0PY

Summary

One hundred and fifty-six Scottish Blackface ewes were differentially group-fed over a 2-month period to achieve three distinct levels of body condition (good, moderate and very poor). Over 5 weeks prior to mating, one group of good-condition ewes was maintained in that condition, one group of good- and one of moderate-condition ewes were brought down in condition by restricted feeding and one group of moderate and the very poor condition ewes were raised in condition by a high level of feeding. Ewes were therefore in good, moderately good or poor condition at mating. After mating, ewes were killed either on return to service or at 25 ± 5 days for counts of corpora lutea and viable embryos.

Poor body condition, irrespective of feeding level, was associated with a delay or suppression of oestrus and with a high return-to-service rate. Ovulation rate was positively related to body condition at mating but not to the level of pre-mating food intake at the condition levels studied.

Embryo mortality decreased as body condition at mating increased and the interaction between condition and the level of pre-mating food intake had a differential effect on mortality of single- and multiple-shed ova. The lowest rate of embryo mortality was found in ewes in moderately good condition which had been well-fed before mating.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1975

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References

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