Pregnancy rates appear to improve when the injection is given at 19 days instead of 17. Most females will show estrus two to three days after the injection. Heat detection is required. This program requires the most planning as it begins 31 days prior to the breeding season. It is also important that each female consume the recommended amount of MGA every day.
Pregnancy rates are more variable on mature cows with calves.
Synchro-Mate B is a common protocol that consists of administering an injection and an ear implant on day 0. The implant is removed on day 9. The cows are watched for signs of standing estrus or are time inseminated 48-54 hours after implant removal. Select Synch is a newer method of estrus synchronization. Females are heat detected from 36 hours before and up to six days following the prostaglandin injection.