Current Concepts for Estrus Synchronization and Timed Insemination

Abstract

The cattle industries have a wide range of reproductive technologies that are available to producers and veterinarians to program reproductive management with the use of estrus synchronization and timed insemination protocols. It is of paramount importance that users of this technology have a thorough understanding of the systems as to how they regulate pituitary, ovarian and uterine function. Major advancements have come about because we now understand how to control and coordinate ovarian follicular, corpus luteum and uterine functions in a manner that is conducive to normal fertility in cattle under different physiological conditions i.e., non-lactation, lactation, anestrus, intensive and extensive management conditions etc. At this meeting in 1998, the various practical systems to control the estrous cycle in dairy animals were reviewed.³⁰ Objective of this presentation is to provide an update of current reproductive strategies for synchronization and timed insemination in dairy and beef cattle. The focus will be with the use of those pharmacological drugs available to the cattle industries in the United States. Effective estrus synchronization programs provide a number of advantages: cows or heifers are in estrus at a predicted time which facilitates AI, and embryo transfer; time and labor expense for detection of estrus are reduced; AI becomes more practical under extensive conditions; precise control of ovulation permits a timed insemination without the need for detection of estrus; and specific timed treatments to improve embryo survival can be implemented effectively.