RESUMO
A common reproductive disease in dairy cattle is Cystic Ovarian Disease. To study its development, there was use of an experimental model of follicular persistence to detect hemodynamic changes occurring in ovaries by using Doppler ultrasonography. After estrous synchronization, control cows received no additional treatment and were evaluated at proestrus (CG), whereas treated cows (PG) received sub-luteal doses of progesterone for 15 days and were evaluated at proestrus, and after 0, 5, 10 and 15 days of follicular persistence. Spectral Doppler was used to evaluate blood flow in the ovarian artery, and power Doppler for evaluation of blood flow in the ovarian parenchyma and follicular wall of persistent and dominant preovulatory follicles. Findings using power Doppler signals indicated there were no differences between groups in the parenchyma of both right (Pâ¯=⯠0.455) and left (Pâ¯=⯠0.762) ovaries. In contrast, power Doppler signals of blood flow were less in walls of persistent follicles from day 0 to 15 when there was follicular persistence than in dominant follicles of the CG (Pâ¯<⯠0.001). Blood flow in ovarian arteries was less (Pâ¯<⯠0.05) in diastolic velocity and time averaged maximum velocity in all PG groups than in the CG. Peak systolic velocity was less (Pâ¯<⯠0.05) in all PG than in the CG, with the exception of P15 (Pâ¯>⯠0.05). These findings indicate there are marked changes in blood irrigation area of walls of persistent follicles during the 15 days of follicular persistence.