Symposium on Reproduction, September 6-7, 1973, School of Veterinary Medicine, University of California, Davis : sponsored by American Veterinary Society for the Study of Breeding Soundness, American College of Theriogenologists, School of Veterinary Medicine, University of California, Davis.

  • Symposium on Reproduction (1973 : Davis, Calif.)
Date:
[1973?]
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Symposium on Reproduction, September 6-7, 1973, School of Veterinary Medicine, University of California, Davis : sponsored by American Veterinary Society for the Study of Breeding Soundness, American College of Theriogenologists, School of Veterinary Medicine, University of California, Davis. Source: Wellcome Collection.

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    1 TITLE: The Mare as an Oddity in Reproductive Endocrinology SPEAKER: Dr. G. H. Stabenfeldt In this discussion I shall emphasize the oddities of equine repro¬ ductive endocrinology. Not to discourage the veterinary practitioner, but a recognition of the oddities of the reproductive cycle of the mare should help the equine practitioner to develop a more rational approach to the management of the cycle of the mare. First, I shall discuss the basic events leading to ovulation from an endocrine viewpoint. The relation¬ ships of endocrine events have been quite well established during the past few years in a number of species. [First slide] I'll use the dog to emphasize the relationship of these events. FSH, and possibly some LH, are first of all necessary for follicular development. The growing fol¬ licles then begin to secrete larger and larger amounts of estrogen, as shown on the slide. At a certain point in time, estrogen levels have a positive feedback on the release of LH, and probably FSH, which results in a short ovulatory burst of these gonadotrophic hormones. Ovulation usually follows this surge of gonadotrophins within 24 hours. The short¬ ness of this surge is emphasized in the next slide [Slide #2], which is from the work of Schalms and Karg in Germany. This slide shows that the LH surge in the cow is initiated and over with within a 12-hour period. The first oddity, then, of the mare's reproductive cycle concerns the breadth of the LH surge, which is seen in conjunction with ovulation. The next slide [Slide #3] is courtesy of Irv Geschwind, in Animal Science, and detects the LH surge in the mare at the time of ovulation.