Endocrine milieu and developmental dynamics of ovarian cysts and persistent follicles in postpartum dairy cows

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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. © 2012 American Dairy Science Association.

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APA

Roth, Z., Biran, D., Lavon, Y., Dafni, I., Yakobi, S., & Braw-Tal, R. (2012). Endocrine milieu and developmental dynamics of ovarian cysts and persistent follicles in postpartum dairy cows. Journal of Dairy Science, 95(4), 1729–1737. https://doi.org/10.3168/jds.2011-4513

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