Reproductive Hormones

The cattle estrus cycle is a cycle of endocrine events associated with morphological changes in the cow's reproductive tract accompanied with certain behavioral traits.

Cows receive estrus in a carefully regulated cycle, which gives repeated opportunities to the animals to become pregnant. It is regulated by the hypothalamic-pituitary-gonadal (ovary) axis producing hormones that dictate reproductive events in cattle.

Hormone Activity in Female Cattle Hormone Activity in Female Cattle

Female Cow Hormones: Description and Function1

Hormone Source Target tissue Primary action
Gonadotropin Releasing Hormone (GnRH) Hypothalamus Anterior lobe pituitary Release of FSH and LH from anterior lobe pituitary
Follicle Stimulating Hormone (FSH) Anterior lobe pituitary Ovary (granulosa cells) Follicular development, estradiol synthesis
Luteinizing Hormone (LH) Anterior lobe pituitary Ovary (theca interna and luteal cells) Stimulates ovulation, formation of corpus luteum and progesterone secretion
Estradiol (E2) Ovary (follicle), placenta Hypothalamus, entire reproductive tract, mammary gland Sexual behavior, elevates secretory activity of the entire tract, enhances uterine motility
Oxytocin Hypothalamus and placenta, synthesized by CL Myometrium and endometrium uterus, mammary gland Uterine motility, promotes uterine PGF2α secretion, milk ejection
Progesterone (P4) Corpus luteum, placenta Uterine endometrium, hypothalamus, mammary gland, myometrium Endometrial secretion, inhibits GnRH release, inhibits reproductive behavior, promotes maintenance of pregnancy
Prostaglandin F2α (PGF2α) Uterine endometrium Corpus luteum, oviduct Luteolysis, promotes uterine tone and contraction, ovulation

References

  1. Senger PL. Pathways to pregnancy and parturition. 2005. ISBN:978-0965764827