Factors affecting conception after synchronization with Lutalyse® and timed insemination

Abstract

With heifers given two injections of Lutalyse 11 days apart, and inseminated 80 hours after the second injection, only 20% in heat before 48 hours conceived compared with 65% that were in heat 48 to 80 hours after injection. Those showing heat early may have been inseminated too late. Heifers receiving their second injection on day 7. 8, or 9 of the cycle came into heat earlier than those injected on days 10 through 15.