Temporal alteration in ovarian follicle fate with hormonal and hemodynamic perspectives during receptive phase of estrous cycle in endometritic cattle.

The present research was carried out to assess the serum progesterone (P₄) concentration and uterine hemodynamics at estrus till ovulation in cyclic cows (N = 130) with healthy or diseased uterus. At estrus, 85 cows were diagnosed with clinical endometritis (CE; n = 44) and sub-clinical endometritis (SCE; n = 41); whereas, 45 cows being served as control namely no endometritis (NE; n = 45) were included in the study. Serum progesterone estimation at 12 - 14 and 40 hr after the onset of estrus and Doppler sonography of both middle uterine arteries were done to envisage the uterine hemodynamics and ovulation. The serum progesterone concentration was significantly higher at 12 - 14 hr after onset of estrus in CE and SCE cows. At 12 - 14 hr after onset of estrus, a cut-off value of ≥ 0.48 ng mL^-1 P₄ was obtained, above which 22.72% CE, 26.82% SCE and only 8.88% NE cows failed to ovulate within 36 - 40 hr of estrus onset. Among the Doppler indices, pulsatility and resistance indices were significantly higher; whereas, volume and velocity indices were significantly lower in NE cows. In cows diagnosed with CE and SCE, a higher supra-basal P₄ concentration, and velocity and volume of blood flow to uterus at estrus negatively affected the duration to ovulation.