Biology of Reproduction, Vol 21, 1203-1207, Copyright © 1979 by Society for the Study of Reproduction

Seasonal Variation in the Nature of Cervical Mucus Response to Estradiol Benzoate in Normal and Clover-Affected Ovariectomized Ewes

¹ CSIRO, Division of Animal Health, Institute of Agriculture, University of Western Australia, Nedlands, Western Australia 6009

Seasonal changes in cervical mucus were studied in 16 ovariectomized ewes, 8 of which had permanent phytoestrogenic infertility. Each ewe was treated with 25 µg estradiol benzoate daily for 3 days every other month over a 16 month period. In all ewes, the total amount of mucus, the amount of dry matter and the spinnbarkeit of the mucus were less in collections made during the normal anestrous period than during the normal breeding season. The proportion of dry matter in the mucus and the degree of arborization were not influenced by season. Mucus from the infertile ewes was reduced in both total weight and amount of dry matter and in spinnbarkeit, but showed a seasonal variation in characteristics similar to that of controls. The seasonal changes in mucus are of a different type from those caused by varying doses of estrogen, suggesting that it is the type of cervical response rather than the degree of response that changes between the normal breeding season and anestrus.

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ACKNOWLEDGMENTS The assistance of M. R. Sanders is appreciated.