Biology of Reproduction, Vol 21, 537-544, Copyright © 1979 by Society for the Study of Reproduction

Ovarian Effects of Bovine Follicular Fluid Treatment in Sheep and Cattle

¹ Department of Veterinary Science, University of Wisconsin, Madison, Wisconsin 53706

Study was made of effects of administration of bovine follicular fluid (FF) on the ovaries of sheep and cattle. The FF was obtained by aspiration of follicles from ovaries obtained at a slaughterhouse. Diestrous ewes treated with prostaglandin F₂ (PG) had an increased interval to estrus when treatment with PG was followed by treatment with whole FF (7.0 ± 0.8 vs 2.0 ± 0.0 days for controls, mean ± SEM). Treatment of diestrous heifers with PG and FF resulted in similar increases in the interval from PG to estrus and ovulation. Laparotomy of ewes and palpation of heifers after treatment with PG indicated no differences in diameters of corpora lutea. Laparotomy of ewes after 8 days of treatment with FF indicated significant follicular inhibition: diameter of largest follicle, 6.3 ± 0.8 vs 2.5 ± 0.3 mm; number of follicles greater than 3 mm, 2.5 ± 0.5 vs 0.0 ± 0.0, for control and treated ewes, respectively. The delay in return to estrus, therefore, was due to inhibition of follicular development rather than to an interference with luteolysis. Crude fractionation of whole bovine FF in an attempt to attribute the biological activity to either a charcoal extractable substance (steroid) or a substance denaturable at 100°C (protein) had mixed results. In the ewe, both charcoal extracted FF and heated FF were as effective as whole FF in delaying estrus. In one experiment with heifers, neither preparation was effective alone, but the combination was as effective as whole FF. When treatment with charcoal extracted FF was repeated in a second experiment, it was found to be effective alone. It was concluded that the bovine FF contained a nonsteroidal substance that had follicle inhibiting activity in cattle and sheep.

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ACKNOWLEDGMENTS This work was supported by the College of Agricultural and Life Sciences and the Graduate School, University of Wisconsin, Madison. Prostaglandin F₂ was donated by Upjohn, Kalamazoo, MI. The authors express their appreciation to Oscar Mayer and Co. for allowing collection of ovaries. The authors thank Dr. B. C. Wentworth for helpful advice and Mr. T. E. Ladell for excellent technical assistance.