COW REPRODUCTIVE HORMONES
To understand the physiological bases of the bovine reproductive system, the generalities of the main reproductive hormones of the female bovine and their interaction are presented here.
GONADOTROPINE LIBERATING HORMONE (GnRh)
- Stimulates the production and release of FSH and LH by the adenohypophysis (anterior pituitary).
- Stimulates the growth and maturation of the ovarian follicle.
- It contributes to the last stage of maturation of the follicle (which has become dominant) to trigger its ovulation.
- It helps so that the clot formed after ovulation becomes a corpus luteum.
- It generates changes in the uterus that favor the transport of sperm.
- It helps to express sexual behavior of female (heat), acting on the central nervous system.
- It also stimulates the release of GnRH.
- It inhibits the release of FSH without altering the release of LH.
- It inhibits the release of GnRh, which will also reduce the levels of FSH and LH. This avoids new ovulations.
- Prepares the uterus to receive an embryo, generating changes in its mucosa so that it can be nourished during the first days of pregnancy.
- It produces the regression or destruction of the corpus luteum (favors luteolysis).
Factors to be considered
- The day on which the release of endometrial PGF-2alpha is given to lyse the luteal body, varies according to the literature:
-On day 16 or 17 (According to E.S.E. HAFEZ).
-On day 14 (According to Cunningham).
-It begins on day 14 after ovulation and produces a decrease on day 18 (According to García Sacristán)
- Low estrogen concentrations together with high concentrations of progesterone, constitute a strong inhibitor of Gonadotropins secretion.
– Cunningham’s Textbook of Veterinary Physiology.
– E.S.E. Hafez. Animal reproduction and artificial insemination.
– García Sacristán. Fisiología veterinaria.