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Metabolic and Endocrine Differences Between Dairy Cows That Do or Do Not Ovulate First Postpartum Dominant Follicles.
Cheong, Soon Hon; Sá Filho, Ocilon G; Absalón-Medina, Victor A; Pelton, Susanne H; Butler, W Ronald; Gilbert, Robert O.
Afiliação
  • Cheong SH; Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York.
  • Sá Filho OG; Department of Animal Science, Cornell University, Ithaca, New York.
  • Absalón-Medina VA; Department of Animal Science, Cornell University, Ithaca, New York.
  • Pelton SH; Department of Animal Science, Cornell University, Ithaca, New York.
  • Butler WR; Department of Animal Science, Cornell University, Ithaca, New York.
  • Gilbert RO; Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York rob.gilbert@cornell.edu.
Biol Reprod ; 94(1): 18, 2016 Jan.
Article em En | MEDLINE | ID: mdl-26632612
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.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Ovulação / Período Pós-Parto / Folículo Ovariano Limite: Animals Idioma: En Ano de publicação: 2016 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Ovulação / Período Pós-Parto / Folículo Ovariano Limite: Animals Idioma: En Ano de publicação: 2016 Tipo de documento: Article