Prolonged Elevated Concentrations of Estradiol Do Not Affect Conception Rates in Beef Cattle

Following treatments causing either prolonged elevated concentrations of estradiol associated with development of persistent follicles or inhibited elevated concentrations of estradiol and development of persistent follicles, conception rates were compared. Beef females received either four norgestomet implants for 9 days (day 0 = treatment initiation; n=59) or one norgestomet implant for 7 days and three additional norgestomet implants for 2 days (n=60). All implants were removed on day 9 followed by estrous detection and AI for 7 days. Treatment and day interacted to affect estradiol concentrations from day 0 to day 9 with elevated estradiol in females treated with one norgestomet implant for 7 days. Conception rates to AI were similar across treatments. Prolonged elevated concentrations of estradiol associated with development of persistent ovarian follicles do not affect fertility when persistent ovarian follicles are not allowed to ovulate