Review of Estrous Syncrhonization Systems: Cidr Inserts

Introduction Although estrous synchronization has been cited over the past several decades to have significant impact on reproductive performance of beef cattle (Schafer et al., 1990), only a limited percent of beef cattle operations in the U.S. synchronize estrus. In a summary by the National Animal Health Monitoring Systems (NAHMS) only 3.3% of beef cattle in the U.S. were being synchronized (NAHMS, 1994) even though estrous synchronization and AI have been documented to increase production and profitability in beef operations (Lesmeister et al., 1973; Bellows and Short, 1990; Wiltbank, 1990). Estrous synchronization is a valuable reproductive tool for beef producers. A survey was conducted in Illinois in 2000 in attempt to understand why producers were not using estrous synchronization (Kesler, 2000). In completing the survey, producers were asked to indicate the reasons (listed in Table 1) they did not synchronize estrus in their heifers and cows. Although there was support for all provided reasons, one factor emerged as the primary reason: lack of time/labor. The second ranked reason was poor results. These are the two most important factors that must be considered in new product development and education. Products that were made available up until the 1990's were limited in efficacy and consistency and may have caused producers to lose interest in or question new developments.