title: Metabolic and Endocrine Differences Between Dairy Cows That Do or Do Not Ovulate First Postpartum Dominant Follicles.
abstract: Most dairy cows develop the first dominant follicle postpartum within 2 wk after calving, but only about 40% of these follicles produce sufficient estradiol to stimulate ovulation despite having normal ultrasound appearance and growth. This study aimed to characterize metabolic, endocrine, and follicular fluid profiles of cows in which the first dominant follicle postpartum will become ovulatory and those with nonovulatory follicles. Luteinizing hormone pulse frequency, follicular fluid androstenedione, and follicular fluid estradiol concentrations were lower in nonovulatory cows suggesting that the function of theca cells is impaired. In addition, nonovulatory cows had more severe negative energy balance and greater insulin resistance postpartum. This study describes for the first time the steroid hormone profile of early postpartum follicles and shows that a steroidogenic defect most likely occurs in theca cells limiting the amount of androgen precursor available for estradiol production that impairs their ovulatory outcome.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York.
authors.forename: Soon Hon
authors.initials: SH
authors.lastname: Cheong
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York.
authors.forename: Ocilon G
authors.initials: OG
authors.lastname: Sá Filho
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Absalón-Medina
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York.
authors.forename: Susanne H
authors.initials: SH
authors.lastname: Pelton
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York.
authors.forename: W Ronald
authors.initials: WR
authors.lastname: Butler
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York rob.gilbert@cornell.edu.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Gilbert
mesh_terms: D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D050260:Carbohydrate Metabolism; D002417:Cattle; D004734:Energy Metabolism; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005298:Fertility; D015571:Follicular Fluid / Q000378:metabolism; D005951:Glucose Tolerance Test; D007333:Insulin Resistance; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D049590:Postpartum Period / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D013799:Theca Cells
chemical_list: D011506:Proteins; D000735:Androstenedione; D004958:Estradiol; D007986:Luteinizing Hormone
keywords: dairy cow; endocrinology; energy; fertility; insulin; ovulation