Comparison of Long-term CIDR-based Estrous Synchronization Protocols on Estrous Response and Pregnancy Rates in Postpartum Beef Cows

Abstract

Estrous synchronization and artificial insemination allow beef producers to maximize genetic improvement in their operations. However, many beef producers have been reluctant to incorporate this technology into their program due to the management requirements it entails. Therefore, any improvements to decrease time and/or labor inputs may increase the use of such technology. The CIDR-Select protocol is an effective method of synchronizing estrus in beef cows. This protocol involves 14 days treatment with a CIDR progesterone insert, GnRH treatment 12 days after CIDR removal, and treatment with prostaglandin F2alpha seven days after GnRH. The entire protocol requires over 33 days, from initial CIDR insertion to detection of estrus and insemination. Reducing the interval from CIDR removal to GnRH treatment would shorten the protocol and potentially make it more attractive for use by producers, providing effectiveness was maintained. The objective of this experiment was to characterize the estrous response and subsequent fertility of postpartum beef cows following synchronization utilizing the CIDR-Select protocol, in which the interval from CIDR removal to GnRH treatment was reduced from 12 to two days.