Hormonal Problems In Show Mares

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218 – March/April, 2017

by Heather Smith Thomas

Mares often exhibit changes in behavior relative to their estrus cycles. These changes are usually hormone-related and the mare returns to her normal attitude and behavior after she goes out of heat. Sometimes the behavior is so extreme that it interferes with training or performance, which can be a frustration to mare owners and riders. They often ask their equine veterinarian about ways to manage the estrus cycle to keep these mares from coming into heat.

Complaints of poor performance, strong estrus behavior distracting a mare from her job or making her more difficult to handle, aggressive attitude or pain (even mild colic due to ovulation) are so common that many people just assume that mares perform below their potential when they are in heat. In a survey of veterinarians taken by the American Association of Equine Practitioners (AAEP) 20 years ago, 90% of the 751 respondents believed that a mare’s estrus cycle played a major role in her athletic performance and only 1% felt that there was no effect of the cycle on performance.

Dr. Ahmed Tibary, Professor of Theriogenology, Department of Veterinary Clinical Sciences, Washington State University, says mare behavior is a huge concern in show horses. “Clients tell me their mare is cranky, difficult to handle, or not performing well, and want to stop her cycles. But we first have to determine whether this behavior is actually due to her cycle, because the unwanted behavior or poor performance may be due to something else,” he says. It also helps to try to determine whether the mare is exhibiting normal or abnormal estrus.

Click here to read the complete article
218 – March/April, 2017