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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    4 lutea. These corpora lutea, however, do not in most cases prolong the diestrous phase of the cycle. The inare thus is sonewhat unique as con- pared to other large domestic species of animals, in that follicular de¬ velopment is not strictly inhibited by luteal phase levels of progestins— in fact, neither at times, is ovulation. Vfe have utilized the measurement of progesterone in the peripheral blood of mares as an indicator of formation of corpora lutea, maintenance of corpora lutea and regression of corpora lutea during the estrous cycle in the mare. The next slide [Slide #11] detects a composite, almost idealized profile of the corpus luteum of the mare during the estrous cycle. As can be seen in this slide, maximal corpus function is obtained by 6th or 7th day postovulation. Regression is very precipitous in the mare as in our other large species, in that it is complete in about 48 hours. It is not generally recognized that corpora lutea can be palpated for some period of time following ovulation. [Slide # 12] John Hughes has found that corpora lutea can be palpated on the average of 9 days post- ovulátion. In some mares they can be palpated the entire lifespan, par¬ ticularly if they are located on the poles of the ovary or if the ovary or the corpora lutea have a particularly resilient nature to them. The mare is also unusual corpared to other large domestic species in that spontaneous prolongation of the corpus luteum occassionally occurs. This is shown by the next slide. [Slide #13]. This prolongation can last from 30-90 days. Estrus is suppressed dixring this time, but not necessarily follicular growth and, at times, ovulation. The next slide JSlide #14J shows an ovary obtained fron one of these