Ovarian response to hCG in the postweaning sow.
Five non-cyclic postweaning sows were given intramuscularly 1,000 IU of hCG on day 2 (4 sows) and day 36 (1 sow) after weaning. Single or multiple follicular cysts were developed in ovaries in all cases. Plasma E2 fluctuated at low levels in 4 of 5 sows resulting in silent heat. The sows which exhibited neither estrus nor ovulation after hCG administration did not display any preovulatory LH surge, and plasma progesterone levels remained low (< or = 1 ng/ml). These results suggest that abnormal follicular growth or impairment of the ovulation process as a consequence of unsatisfactory LH release after hCG treatment in swine with ovarian inactivity may promote the formation of ovarian cysts.
Ogasa
A
A
Department of Animal Reproduction, Nippon Veterinary and Animal Science University, Tokyo, Japan.
Tsutsui
T
T
Kawakami
E
E
D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004958:Estradiol / Q000097:blood; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood; D010048:Ovarian Cysts / Q000139:chemically induced / Q000662:veterinary; D006080:Ovarian Follicle / Q000187:drug effects; D010053:Ovary / Q000187:drug effects*; D010060:Ovulation / Q000187:drug effects; D011374:Progesterone / Q000097:blood; D013552:Swine / Q000097:blood / Q000502:physiology*; D013553:Swine Diseases / Q000139:chemically induced; D014886:Weaning
D006063:Chorionic Gonadotropin; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone