Understanding Postpartum Anestrus and Puberty in the Beef Female

Management of the beef female for reproductive success, both before and after puberty, plays a major role in determining the efficiency of any beef production system. Two of the most critical physiological periods associated with female reproduction are the prepubertal and postpartum periods. Therefore, a general understanding of the processes that underlie developmental changes in the heifer during pubertal development, and in the sexually-mature female during and after calving, can aid in understanding the basis of established management protocols. The prepubertal and postpartum periods are characterized, at least in part, by a state of anestrus or the absence of estrous cycles. Interestingly, many of the hormonal deficits limiting reproduction in the prepubertal heifer are similar to those observed in the cow during postpartum anestrus. However, the fundamental bases leading to reproductive inactivity differ. In the former, the hormonal and physiological changes preceding first ovulation occur as a result of maturational changes within the central nervous system, which ultimately trigger normal ovarian function, the onset of regular estrous cycles, and the potential to become pregnant. During the postpartum anestrus period of the sexually mature female, hormonal changes reflect the re-establishment of a process that is already fundamentally in place. The purpose of this communication is to review the basic physiological processes that control puberty and postpartum anestrus in female cattle and the genetic, nutritional, and managerial factors that influence them.