When it comes to estrus suppression, is mare a four-letter word?

Abstract

Perceived misconduct in mares is often suspected of being associated with estrous behaviors and may or may not be directly connected to the estrous cycle. Mares are seasonally polyestrus and based on the presence or absence of reproductive hormones, specifically estrogen and progesterone, their behavior can vary throughout the year. Concerns pertaining to mares’ behavior are often attributed to their estrous cycle; however, undesirable behaviors need to be differentiated from other abnormal behaviors from nonreproductive causes. Although multiple treatments have been utilized by veterinarians for estrus suppression and manipulation, some of them are poorly effective whereas others may actually promote estrous behavior. Treatments can be categorized as progestogen supplementation, prolonging the luteal phase, suppression of ovarian follicular activity, and ovariectomy. This review details the individual therapies available for the potential treatment of estrous behavior and each therapy’s associated efficacy.