title: Ovarian stimulation with follicle-stimulating hormone under increasing or minimal concentration of progesterone in dairy cows.
abstract: The objective of this study was to investigate the effect of the presence or absence of Corpus luteum (CL) on the follicular population during superstimulation in dairy cows (Holstein-Friesian cattle). Animals were divided into two groups as follows: (1) Growing CL group (G1): Cows (n=7) received a total dose of 28 Armour units (AU) follicle-stimulating hormone (FSH) through the first 4 d (twice daily) after spontaneous ovulation (Day 0). (2) CL Absence group (G2): Cows (n=10) received prostaglandin F(2alpha) (PGF(2alpha)) at 9 or 10 d after ovulation. After 36h, all the follicles (larger than 5mm) were aspirated (Day 0). The FSH treatment started 24h after aspiration and continued for 4 d. The number of small (3 to <5mm), medium (5 to <8mm), and large (> or = 8mm) follicles was examined on Days 1, 3, and 5 in all groups. Blood samples were collected daily for 5 d, and progesterone (P(4)), estradiol (E(2)), insulin-like growth factor-1 (IGF-1), and growth hormone (GH) in plasma were measured by enzyme immunoassays. The results showed that in G1, the P(4) level increased gradually from 0.5 ng/mL at Day 1 to 2 ng/mL at Day 5, whereas in G2, the P(4) level was completely below 0.5 ng/mL. All cows of the G2 group showed an increase of E(2) at Day 3 or Day 4 followed by an increase of IGF-1 within 24h, while GH increased concomitantly with the E(2) increase in 8 of 10 trials. On the other hand, cows of the G1 group showed neither E(2) nor IGF-1 increase. Moreover, at the end of the treatment, the number of follicles in the G2 group was significantly increased compared with that of the G1 group (22.8+/-2.0 vs. 11.6+/-2.0). In conclusion, low P(4) level during FSH treatment enhanced multiple follicular growth and E(2) secretion, which was followed by increase of IGF-1 and GH. Therefore, the absence of the CL may play a critical role in the superovulation response by controlling the number of growing follicles.
authors.affiliation: Department of Theriogenology, Assiut University, Assiut, Egypt. timorsherry@yahoo.com
authors.forename: T M
authors.initials: TM
authors.lastname: El-Sherry
authors.forename: M
authors.initials: M
authors.lastname: Matsui
authors.forename: K
authors.initials: K
authors.lastname: Kida
authors.forename: A
authors.initials: A
authors.lastname: Miyamoto
authors.forename: G A
authors.initials: GA
authors.lastname: Megahed
authors.forename: S H
authors.initials: SH
authors.lastname: Shehata
authors.forename: Y-I
authors.initials: YI
authors.lastname: Miyake
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D003338:Corpus Luteum / Q000502:physiology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage* / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D006080:Ovarian Follicle / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*; D011374:Progesterone / Q000097:blood / Q000378:metabolism*; D014463:Ultrasonography
chemical_list: D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone