Potency in male rhesus monkeys: effects of continuously receptive females.

Ejaculations decreased and mount latencies increased when intact males were paired regularly over a 3.5-year period (3180 tests) with ovariectomized females made constantly receptive by daily injections of estradiol. The deterioration in potency was abruptly and completely reversed by substituting a group of new but similarly treated females for the original ones.