Animal Science Department


Date of this Version

December 2003


Published for Proceedings, The Range Beef Cow Symposium XVIII December 9, 10, and 11, 2003, Mitchell, Nebraska.


Estrous synchronization has become a powerful tool in managing breeding seasons to compliment niche markets. Synchronization of estrus, along with the use of AI, has become a popular technology that can introduce new sire genetics along with control of the breeding and calving season. Cattle producers have long searched for methods to efficiently and effectively synchronize females for artificial insemination without compromising conception or pregnancy rates versus conventional natural service breeding. Over the past 40 years, research scientists have developed and tested many synchronization protocols to synchronize estrus and ovulation in beef and dairy cattle with a goal to consistently produce acceptable pregnancy rates. Success in meeting these goals has been limited. Current approaches to synchronization have included the use of progestins (MGA & CIDR-B), prostaglandins (PGF2_), and gonadotropin-releasing hormones (GnRH; Table 1).