Application of the CIDR-B to Estrous Synchronization in Beef Cattle

Progesterone, or progesterone like compounds, (progestins) have been investigated and used for estrous synchronization for several decades. However, the success rates of programs that use progestins have varied considerably. A primary challenge to the use of this hormone for synchronization was the repeated observation in the past of reduced fertility at the synchronized estrus. Perhaps of even greater impediment to the development and adoption of this technology was that we did not understand why these negative responses were occurring or what modifications were necessary to make corrections. Research findings over the past decade have, however, helped to describe why fertility is impaired in some situations when progestins are used. More importantly, this knowledge has been applied toward developing systems that permit the use of progestins while avoiding some of the previously observed detrimental responses. Thus, we are now in a position to capture the benefits of the advantages of using progesterone without sacrificing fertility.