Record Details
Some hormonal factors associated with the regulation of ewe reproductive patterns
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Some hormonal factors associated with the regulation of ewe reproductive patterns |
| Names |
Reeves, Jerry John
(creator) Ellington, Earl F. (advisor) |
| Date Issued | 1967-05-09 (iso8601) |
| Note | Graduation date: 1967 |
| Abstract | Twenty-eight Columbia ewes were made available for study during their breeding and anestrous seasons. After the regularity of the estrous cycles had been established, eight of the ewes were sacrificed in pairs at four different stages of the estrous cycle. Eight additional ewes were sacrificed during anestrus. Pituitary glands, ovaries, uteri, thyroids and adrenals were grossly observed, removed and weighed. The anterior pituitaries were lyophilized and assayed on a unit weight basis for gonadotropic content by the use of hypophysectomized, immature, female rats. Mean gonadotropic activity of the anterior pituitaries, as indicated by the ovarian weight response in the rats, was higher during the anestrous season than during the breeding season. Mean ICSH activity, as indicated by stimulation of the ovarian interstitial tissue of the rats, was simila for both seasons, while mean FSH activity, as indicated by ovarian follicle diameter in the assay rats, was significantly higher during anestrus than during the breeding season. Mean ovarian follicular activity in the ewes as indicated by measuring the diameter of the largest follicle appeared comparable between the two seasons. The pituitary gland was significantly heavier during anestrus, while the ovary and uterus were both significantly larger during the breeding season. Significant differences between seasons were not noted with respect to mean thyroid and adrenal weights of the ewes. The breeding season was found to be 235 days in length while anestrus was 130 days in length. |
| Genre | Thesis/Dissertation |
| Topic | Sheep -- Breeding |
| Identifier | http://hdl.handle.net/1957/47179 |
