Date of Award:

1990

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Advisor/Chair:

Warren C. Foote

Abstract

The relationships of estradiol-17-beta, progesterone, and LH in the early postpartum St. Croix ewe were monitored during the breeding season in 1988. A second group of non-postpartum, ovariectomized St. Croix ewes were used to determine non-ovarian levels of progesterone for comparison. Results of this study indicate that:

1. The short duration rise in progesterone exhibited by some ewes is indicative of an ovulation.

2. Ewes that do exhibit a short luteal phase prior to the first "normal" luteal phase have a longer period from parturition to the first "normal" luteal phase.

3. Serum levels of LH increase beginning 3 days postpartum.

4. There is a strong relationship between the concentration of estradiol and the exhibition of behavioral estrus in the postpartum ewe.

5. There appears to be a definite but somewhat irregular pulsatile release pattern of estradiol from the follicle of the postpartum ewe.

The ability of the endocrine system of the St. Croix to return to functional levels of production and release during the first 15 days postpartum is likely related to their relatively short postpartum intervals and subsequent pregnancies.

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