Relationships between the antral follicle count steroidogenesis and secretion of follicle-stimulating hormone and anti-Müllerian hormone during follicular growth in cattle

摘要

Schematic of the experimental design. The estrous cycles and follicular waves of cows were synchronized using hormonal treatments and follicular ablation between days − 18 and 0 [ ]. On day 4, PGF was injected to induce estrus. After 40 h, a dominant follicle just before the LH surge was aspirated and collected follicular fluid was defined as the ovulatory phase (day 6). Soon after follicular aspiration, GnRH was injected to induce luteinization of the dominant follicle. After 7 days, a dominant follicle growing with a corpus luteum was aspirated and collected follicular fluid was defined as the luteal phase (day 13). All visible follicles were then ablated. Four days later, the largest follicle was aspirated, and collected follicular fluid was defined as the selection phase (day 17). In three cows (1 low AFC and 2 high AFC), follicular ablation was performed again on day 16 and follicular fluid was collected on day 20. During days 0 to 16, we collected blood samples and monitored ovaries by ultrasonography daily