Using Proven Genetics in an AI Program*

Introduction The development of methods to synchronize estrus in beef cattle has been refined to a point that is feasible as well as reasonable to obtain pregnancy rates in mixed populations of cycling and anestrous cows that exceed 50% to a single fixed-time artificial insemination, provided a progestin based estrus synchronization protocol is used (Lamb et al., 2001; Kojima et al., 2002; Perry et al., 2002; Kojima et al., 2003a, 2003b; Bremer et al., 2004; Stegner et al., 2004; Bader et al., 2005; Schafer et al., 2005; and Larson et al., 2006). However, despite this level of success, recent surveys indicate that fewer than 10% of beef cows in the U.S. are bred artificially. Perhaps part of the reason for the low adoption rate of these technologies is due to the fact that there is little if any documented evidence of the economic value that is added as a result of this change in breeding management. Furthermore, to the knowledge of the authors there has been no published data regarding the differences in value that may be attained over time from both terminal groups of animals and replacement females, sired by bulls: 1) in a natural service setting; 2) the result of AI to older sires with predictable expected progeny differences; or 3) younger AI sires with limited data available to support their expected progeny differences. Therefore, the objective of this experiment was to determine the economic impact of using proven genetics in an AI program. Terminology & Abbreviations AI – Artificial Insemination EPD – Expected Progeny Difference High Accuracy Sires (HAS) – AI Sires with accuracies 0.85 for BW, WW, and YW EPDs at the time of synchronization and AI Low Accuracy Sires (LAS) – AI Sires with accuracies < 0.85 for BW, WW, and YW EPDs at the time of synchronization and AI Calving Ease Sires (CES) – AI Sires with high accuracies that were bred exclusively to virgin heifers NS – Natural Service used after one round of fixed-time AI