Hormonal mechanisms regulating follicular wave dynamics I: Comparison of follicle growth profiles under different physiological conditions in heifers

Follicle diameter deviation has been identified as the pivotal morphological manifestation of follicle selection, however, many of the hormonal mechanisms leading to this key event and regulating variation between individual follicular waves remain undefined. This study compared circulating FSH, LH, and P4 with the follicular dynamics during three different physiological conditions. We hypothesized that these end-points would: 1) be similar for a spontaneous wave 2 vs one induced by follicular aspiration, 2) but would differ between wave 1 and 2, and 3) between conventional (F2 > 7.0 mm at deviation) vs undersized (F2