ESTRUS SYNCHRONIZATION IN BEEF FEMALES WITH NORGESTOMET AND ESTRADIOLVALERATE .2. FACTORS LIMITING AND ENHANCING EFFICACY

Syncro-Mate B(R) (Rhone Merieux, Inc., Athens, GA) is an effective pro cedure to synchronize estrus in beef cattle. The procedure utilizes an injection that contains norgestomet, a synthetic progestin, and estra diol valerate and a norgestomet implant that is left in situ for 9 day s. Removal of the implant allows for expression of fertile estrus appr oximately 30 to 56 hours later. Females may be timed bred approximatel y 48 to 54 hours after implant removal with approximately 40% of the t reated females carving as a result of the timed insemination. Pregnanc y rates have been somewhat variable because of non-synchronization (14 % in this study), luteal dysfunction (9% in this study), stress, and o ther factors described herein.