Animal Science Department


Date of this Version

December 2007


Published for the Proceedings, The Range Beef Cow Symposium XX December 11, 12 and 13, 2007 - Fort Collins, Colorado.


Estrous synchronization and artificial insemination (AI) are reproductive management tools that have been available to beef producers for over 30 years. Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse superior genetics into their operations at costs far below the cost of purchasing a herd sire of similar standards. These tools remain the most important and widely applicable reproductive biotechnologies available for beef cattle operations (Seidel, 1995). However, beef producers have been slow to utilize or adopt these technologies into their production systems.

Several factors, especially during early development of estrous synchronization programs, may have contributed to the poor adoption rates. Initial programs failed to address the primary obstacle in synchronization of estrous, which was to overcome puberty or postpartum anestrus. Additionally, these programs failed to manage follicular waves, resulting in more days during the synchronized period in which detection of estrus was necessary. This ultimately precluded fixed-time AI with acceptable pregnancy rates. More recent developments focused on both corpus luteum and follicle control in convenient and economical protocols to synchronize ovulation. These developments facilitated fixed-time AI (TAI) use, and should result in increased adoption of these important management practices (Patterson et al., 2003). Current research has focused on the development of methods that effectively synchronize estrous in postpartum beef cows and replacement beef heifers by decreasing the period of time over which estrous detection is required, thus facilitating the use of TAI (Lamb et al., 2001, 2006, Larson et al., 2006). This new generation of estrous synchronization protocols uses two strategies which are key factors for implementation by producers because they: 1) minimize the number and frequency of handling cattle through a cattle-handling facility; and 2) eliminate detection of estrus by employing TAI.

Alas, the extensive nature of most beef cattle operations and labor intensity associated with reproductive technologies, such as AI and synchronization tends to drive people away from utilizing this technology, yet the financial and genetic advantages have been extensively documented. Ultimately, the single largest reason for the failure of an AI program is due to poor management, resulting in poor reproductive performance, which causes poor responses to reproductive management. Therefore, producers should use synchronization and AI to enhance the profitability of a well-managed operation, but should not use synchronization and AI to obtain a well-managed operation!! Focusing on the details to taking care of the health, nutrition, and other management factors are critical to the success of an AI program. As cattle producers we need to be aware that numerous short- and long-term factors contribute to females conceiving to a AI, maintaining the embryo/fetus to term, delivering the calf without assistance, and raising and weaning a healthy calf.