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Fertility in Scottish Blackface ewes as influenced by climatic stress

Published online by Cambridge University Press:  27 March 2009

J. G. Griffiths ,
R. G. Gunn  and
J. M. Doney
J. G. Griffiths
Affiliation:
Hill Farming Research Organization, 29 Lauder Road, Edinburgh 9
R. G. Gunn
Affiliation:
Hill Farming Research Organization, 29 Lauder Road, Edinburgh 9
J. M. Doney
Affiliation:
Hill Farming Research Organization, 29 Lauder Road, Edinburgh 9
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Summary

Sixty-four Blackface ewes in moderately fat body condition, were divided into two groups at 17 days before a chemically synchronized mating. One group was penned indoors (sheltered group), the other group penned outdoors in a climatically exposed position and subjected to artificial wetting for 6 h daily (exposed group). The ewes were fed a maintenance ration of 1350 g pelleted dried grass/head/day indoors and 1500 g outdoors.

The treatment was continued from 17 days premating to 25 ± 3 day post-mating. Immediately after mating 16 ewes from each group were interchanged between the two environments. Matings and returns to service were recorded, and at 25 ± 3 days after first mating the ewes were slaughtered. Counts were made of active corpora lutea and embryos; retarded embryos were distinguished. Fresh weights of the ovaries, pituitary, thyroid and adrenal glands were obtained.

Body condition of the ewes within the two environments was maintained. The mean ovulation rates of ewes holding to first service were significantly different (exposed group, 1·52; sheltered group, 1·86). There was no difference between the treatment groups in the number of ewes returning to service, but there was some difference in partial embryo loss, most of which occurred outdoors on or about day 14 or 15 postmating. The results suggest that ovulation rate and possibly early embryo mortality can be influenced by cold stress.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 75 , Issue 3 , December 1970 , pp. 485 - 488
Copyright
Copyright © Cambridge University Press 1970

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