Can Equine Ovariectomies Be Justified on Behavioral Grounds?

While removing mares’ ovaries can be successful in remedying aggressive behavior, other estrous behaviors can persist even following surgery.
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Can Equine Ovariectomies Be Justified on Behavioral Grounds?
content: %22While removing mares’ ovaries—via a surgical procedure called an ovariectomy—can be successful in remedying aggressive behavior, other estrous behavior can persist even following surgery. | Photo: Courtesy Dr. James Crabtree
When mares behave badly, we are often quick to blame their reproductive hormones. And, typically, we want a quick fix. Could removing these mares’ ovaries—via a surgical procedure called an ovariectomy—be a viable solution? James Crabtree, BVM&S, CertEM, MRCVS, director of Equine Reproductive Services, in the U.K., aimed to answer this question during a presentation at the 2017 American Association of Equine Practitioners convention, held Nov. 17-21 in San Antonio, Texas.

Undesirable behaviors clients often report in their mares, said Crabtree, include overt reproductive behaviors (e.g., squatting and peeing), aggression toward horses or people, and, in most cases, difficulty training or an unwillingness to respond to the rider.

To truly tie these to the mare’s hormones, he said the veterinarian must first demonstrate a relationship between behavior and cyclic ovarian activity. One of the best ways to do this is to have the owner keep a diary, said Crabtree.

The veterinarian must also rule out other sources of pain (e.g., back or sacroiliac problems, hind-limb lameness, saddle fit, dental pain, gastric ulcers, granulosa cell tumors, etc.) and perform a gynecological exam to detect abnormalities, along with an endocrine exam to measure hormone levels.

Once the veterinarian confirms hormones are to blame, “can we justify ovariectomy on grounds of behavior?” Crabtree asked

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Written by:

Alexandra Beckstett, a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as assistant editor of its book division, Eclipse Press, before joining The Horse. She was the managing editor of The Horse for nearly 14 years and is now editorial director of EquiManagement and My New Horse, sister publications of The Horse.

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