title: Relationship between metabolic hormones and ovulation of dominant follicle during the first follicular wave post-partum in high-producing dairy cows.
abstract: Recent studies suggest that IGF-I is a crucial regulatory factor in follicular growth during early post-partum period. The aim of the present study was to determine in detail the changing profiles of metabolic and reproductive hormones in relation to ovulation of the dominant follicle (DF) of the first follicular wave post-partum in high-producing dairy cows. Plasma concentrations of related hormones in 22 multiparous Holstein cows were measured from 4 weeks pre-partum to 3 weeks post-partum, and the development of DF was observed with colour Doppler ultrasound. Thirteen cows showed ovulation by 15.2 days post-partum. Anovulatory cows showed higher GH and lower IGF-I levels than those in ovulatory cows during the peri-partum period. Each DF developed similarly, and a clear blood flow in the follicle wall was observed despite ovulation or anovulation. In addition, detailed endocrine profiles were analyzed in 9 out of the 22 cows. Five cows showed an increase in plasma oestradiol-17beta (E2) with follicular growth followed by E2 peak, LH surge and ovulation. In these cows, plasma IGF-I concentrations remained high until 10 days post-partum followed by a gradual decrease. Subsequently, the insulin level increased together with the E2 peak towards ovulation. These profiles were not observed in anovulatory cows. In conclusion, our data strongly support the concept that IGF-I and insulin represent 'metabolic signals' of the resumption of ovarian function post-partum in high-producing dairy cows. Moreover, we provide the first visual evidence that both ovulatory and anovulatory DFs of the first follicular wave post-partum are similarly supplied with active blood flow.
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Kawashima
authors.forename: Saori
authors.initials: S
authors.lastname: Fukihara
authors.forename: Mayumi
authors.initials: M
authors.lastname: Maeda
authors.forename: Etsushi
authors.initials: E
authors.lastname: Kaneko
authors.forename: Carlos Amaya
authors.initials: CA
authors.lastname: Montoya
authors.forename: Motozumi
authors.initials: M
authors.lastname: Matsui
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Matsunaga
authors.forename: Katsuya
authors.initials: K
authors.lastname: Kida
authors.forename: Yoh-Ichi
authors.initials: Y
authors.lastname: Miyake
authors.forename: Dieter
authors.initials: D
authors.lastname: Schams
authors.forename: Akio
authors.initials: A
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D002417:Cattle / Q000502:physiology*; D005260:Female; D005298:Fertility; D005640:Follicle Stimulating Hormone / Q000097:blood; D005498:Follicular Phase / Q000097:blood; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D049590:Postpartum Period / Q000097:blood*; D011247:Pregnancy; D013004:Somatostatin / Q000097:blood*
chemical_list: D015415:Biomarkers; D007328:Insulin; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone