EFFECT OF THE ESTROUS-CYCLE ON PERFORMANCE IN ATHLETIC MARES

Caring for performance horses is an important facet of equine practice . A great deal of research relating to the estrous cycle and reproduct ive performance in brood mares has been published, but little informat ion is available concerning the effects of the estrous cycle on athlet ic performance in mares. Trainers who are involved in various componen ts of the equine industry frequently report that variations in the per formance of a mare are apparently related to the estrous cycle. These concerns involve the aggressive nature of a mare, difficulties in trai ning or riding mares, the presence of back pain or hindquarter pain, o r undesirable estrus behavior in performance situations. Some problema tic behavior traits have been associated with the estrus phase of the cycle, but problems have also been noted during diestrus. In some mare s, it is difficult to associate problematic behavior with either phase of the reproductive cycle. This article discusses the physiologic and endocrinologic events of the mare's reproductive cycle. The most comm on abnormal behavioral problems associated with the estrous cycle are considered. The advantages and disadvantages of treatment options are outlined. Each treatment method discussed has been used successfully. The most common therapy involves the use of altrenogest. Field trials with progesterone implants have also been successful.