Should I Consider Spaying My Mare?

Many mares can be difficult to work with when they are cycling. Most of us have experience with cranky, even aggressive mares that cause havoc when they are in heat.

These behavioral issues are commonly managed with daily oral altrenogest (Regu-Mate®), which, while effective, also carries human health risks. Other options, such as injectable hormones, hormone implants and intra-uterine devices, vary in effectiveness and cost, and the response differs considerably from horse to horse.

Most people spay their female dogs and cats for health reasons and population control. Likewise, it is standard practice to castrate male horses for behavioral reasons, safety and ease of management.

So why is it relatively uncommon to spay mares? One reason is perception. Most owners (and some veterinarians) view removing ovaries in mares as difficult and risky. Historically speaking, this was true. Ovariectomy usually involved general anesthesia and was associated with serious complications. Fortunately, this has changed in recent years. Laparoscopy has become the preferred approach for elective ovariectomy for behavioral reasons and most ovarian tumors.

Laparoscopy is a minimally invasive technique, performed with the mare sedated and standing. There are risks with any surgery; however, the potential benefits of laparoscopy include less surgical trauma, less blood loss and less discomfort. The hospital stay and recovery time are often shorter. Mares can usually return to work within approximately three weeks after laparoscopic ovariectomy (versus three months with a traditional approach).

So if you don’t plan to breed your mare, and you are tired of daily hormone therapy (and her bad attitude), ask your veterinarian about minimally invasive ovariectomy.

– Michelle Delco, DVM, Diplomate ACVS

Dr. Delco is a board-certified equine surgeon at Pilchuck Veterinary Hospital and one of the few surgeons in the Pacific Northwest with specialized training in laparoscopic surgery in horses.