title: Endocrine milieu and developmental dynamics of ovarian cysts and persistent follicles in postpartum dairy cows.
abstract: Ovarian follicular cysts and persistent follicles are follicular pathologies involved in reduced fertility of dairy cows. Two separate experiments were performed on high-yielding Holstein cows to characterize ovarian cyclicity and evaluate the developmental dynamics of follicle pathologies postpartum. In experiment 1, 58 cows were monitored by ultrasonography twice weekly from d 18±1 to 69±2 postpartum. First ovulation occurred 38±3, 27±2, 20±1, and 25±3 d postpartum in cows with 1 cycle (n=11), 2 cycles (n=21), 3 cycles (n=13), and 4 cycles (n=7), respectively. Follicular pathologies were developed in cows that were either acyclic (n=6) or had 1 or 2 cycles, but not in cows with more than 2 cycles. In experiment 2, 47 cows were monitored twice weekly from 10 d postpartum to second ovulation. Follicles ≥17 mm in diameter in 2 consecutive scans were aspirated, and concentrations of various hormones were measured. Cows were defined as cyclic (n=30; 64%) or with the potential to develop follicular pathology (n=17; 36%). Aspirated follicles (n=27) were classified into 3 main groups based on follicular growth rate, follicular diameter, and ovarian activity before and after follicular aspiration. Dominant follicles (n=4) were defined as large follicles (20 mm in diameter) with growth rate ≤1 mm/d and normal ovarian activity. Persistent follicles (n=6) had the same growth rate and diameter as the dominant follicles, but persisted at the same diameter for ≥10 d. Ovarian cysts (n=17) were defined as the largest follicular structures (19 to 32 mm in diameter), with abnormal growth rate (>1 mm/d) and abnormal ovarian activity. Single or turnover cysts did not differ in their growth parameters and were therefore combined and further classified according to follicular-fluid hormone concentrations. Estradiol-dominant cysts (n=7) were characterized by normal estradiol (284 to 659 ng/mL) and progesterone (20 to 113 ng/mL) concentrations, similar to those of the dominant follicle (554 to 993 ng/mL and 44 to 106 ng/mL, respectively). Progesterone-dominant cysts (n=5) were characterized by low estradiol (0.06 to 330 ng/mL) and high progesterone (586 to 3,288 ng/mL) concentrations. Low-steroidogenic active cysts (n=5) were characterized by low concentrations of both estradiol (23 to 61 ng/mL) and progesterone (17 to 205 ng/mL). Characterization of spontaneously forming cysts might enable definition of the formation of ovarian follicular pathologies in postpartum cows.
authors.affiliation: Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University, Rehovot 76100, Israel. roth@agri.huji.ac.il
authors.forename: Z
authors.initials: Z
authors.lastname: Roth
authors.forename: D
authors.initials: D
authors.lastname: Biran
authors.forename: Y
authors.initials: Y
authors.lastname: Lavon
authors.forename: I
authors.initials: I
authors.lastname: Dafni
authors.forename: S
authors.initials: S
authors.lastname: Yakobi
authors.forename: R
authors.initials: R
authors.lastname: Braw-Tal
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D004958:Estradiol / Q000032:analysis; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry*; D006728:Hormones / Q000032:analysis*; D010048:Ovarian Cysts / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D006080:Ovarian Follicle / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D011374:Progesterone / Q000032:analysis / Q000097:blood; D011644:Puerperal Disorders / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D014463:Ultrasonography
chemical_list: D006728:Hormones; D011374:Progesterone; D004958:Estradiol