According to a recent study from the U.S., removing the ovaries of mares can prevent unwanted behavior and reduce pain, even if hormone treatment has not worked before.
From March to November, mares are in heat, which means they are ready to mate for about two to twelve days every three weeks. Estrus is hormonally controlled and often leads to moody, sensitive and sometimes even aggressive behavior in mares, often making them extremely difficult to handle. In some cases, mares also suffer from severe pain in the abdominal area during the period when they are ready to mate.
Hormone therapy can prevent the heat
If the signs of estrus are particularly severe or last for a long time, one way to alleviate the symptoms is hormone therapy. Oftentimes Regumate, a liquid feed supplement to be taken orally, which will prevent estrus and, ideally, all of its related behaviors, is being used for this kind of therapy.
Success rate particularly high with ovariectomy
According to a study of 51 mares from the U.S. published in July, an ovariectomy is another particularly effective option for alleviating estrus symptoms. This surgical procedure removes the mare’s ovaries, making it particularly successful in relieving estrus-related behavior.
Ten horses in the study showed no estrus or unwanted behavior six months after surgery. Nine of the mares exhibited massive behavioral problems prior to treatment and suffered from tumorous changes in the ovaries. Five of the ten horses had failed therapy with Altrenogest prior to having their ovaries removed.
Overall, ovariectomy was successful in nine out of ten cases in the remaining 41 horses. This means that the symptoms were completely eliminated, even if the horse had previously been treated unsuccessfully with Altrenogest. According to assistant professor of equine surgery at the University of Tennessee, Knoxville, Elizabeth M. Collar, DVM, PhD, Dipl. ACVS-LA, some mares still showed minor signs of estrus after the procedure, but significant signs were no longer present.
Ovariectomies may become more important in the future
The surgery can take place without general anesthesia and with the mare being in a standing position. This low surgical risk and high success rate contribute significantly to the possibility that ovariectomies could become a routine procedure in the future.
According to Collar, this type of surgery can help horses live more comfortable lives and improve their relationships with people. In addition, she says, “We regularly geld stallions so as to have more manageable male horses, yet ovariectomy to remove the female sex organs and hormones is far less common in horses,” she said. “There are many sales posts out there looking for ‘geldings’ only. My hope is that people will realize they can buy a mare and have a ‘gelding’ by pursuing ovariectomy[…].“