The response of the 2 largest follicles, identified at day 10 or day 14 of the estrous cycle in ewe, was determined by injecting exogenous gonadotropins. The largest follicle marked on the 10th day of the estrus cycle ovulated only when the ewes were given gonadotropins (control 0/5; treated 4/5), while when marked on the 14th day, it did not require gonadotropin injection to ovulate (control 4/5; treated 3/4). The 2nd largest follicle marked on the 10th or 14th day ovulated in 60% and 50% of the treated ewes respectively, while nontreated ewes did not ovulate any of the 2nd largest follicles at the ensuing estrous.