Follicular activity and ovulation regulated by exogenous progestagen and PMSG in anestrous ewes

Abstract Follicular dynamics and ovulation were compared in 3 groups of anestrous ewes: those treated with medroxyprogesterone acetate (MAP) sponges for 12 d, then with 750 IU PMSG at the time of sponge removal (P4+PMSG, n=6), or PMSG alone (n=6) and untreated controls (n=6). Waves of follicular activity were observed in all the animals. In the P4+PMSG treatment group, MAP priming permitted more ovulatory follicles (P 4 mm when P4 levels were