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

Authors

Karol Fike, University of Nebraska-LincolnFollow
Michael Wehrman, University of Nebraska-Lincoln
Ellen G. M. Bergfeld, University of Nebraska-LincolnFollow
Freddie Kojima, University of Nebraska-Lincoln
James E. Kinder, University of Nebraska-LincolnFollow

Date of this Version

1-1-1998

Comments

Published in Nebraska Beef Cattle Report 1998, published by Agricultural Research Division, University of Nebraska Cooperative Extension, and Institute of Agriculture and Natural Resources, University of Nebraska–Lincoln.

Abstract

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.