title: Effects of induction of ovulation with GnRH or HCG on follicular and luteal blood flow in Holstein-Friesian heifers.
abstract: The objective of this study was to compare the effects of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on follicular blood flow (FBF) during the pre-ovulatory period and on luteal blood flow (LBF) during dioestrus in Holstein-Friesian heifers. Twelve animals were randomly divided into two groups and treated with either intramuscular injection of 100 μg GnRH or intravenous (IV) injection of 5000 IU hCG on Day 0 (oestrus, 48 h after administration of PGF(2α) ) to induce ovulation. Follicular size (FS), FBF and time of ovulation were recorded with colour Doppler sonography at 0, 1, 3, 6, 12 and 24 h after GnRH and hCG treatment. Luteal size (LS) and LBF were investigated on Day 9 and 12 after ovulation. Plasma samples were taken to determine total oestrogens (E(tot) ) and progesterone (P(4) ) after each examination. Ovulation occurred between 24 and 48 h after treatment in all animals. No difference (p > 0.05) was observed in FS between the two treatment groups. Follicular blood flow was higher in the hCG group than that was in GnRH group at 1 h after treatment (p < 0.01). Total oestrogens were also higher (p < 0.01) in the hCG group than GnRH group; however, this difference was only obvious at 12 h after treatment. No difference (p > 0.05) was observed in LS, LBF or P(4) levels on Day 9 and 12 between treatment groups. In conclusion, the results suggest that induction of ovulation with hCG and GnRH has a temporary effect on FBF and oestrogen levels while no effect on the size of corpora lutea, LBF and P(4) levels was observed.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey. Selim.Aslan@veterinary.ankara.edu.tr
authors.forename: S
authors.initials: S
authors.lastname: Aslan
authors.forename: D
authors.initials: D
authors.lastname: Arslanbas
authors.forename: N
authors.initials: N
authors.lastname: Beindorff
authors.forename: H
authors.initials: H
authors.lastname: Bollwein
mesh_terms: D000818:Animals; D002417:Cattle; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003338:Corpus Luteum / Q000098:blood supply*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000098:blood supply*; D010062:Ovulation Induction / Q000662:veterinary*
chemical_list: D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone