HealthWatch: Colic Surgery for Older Horses

Topics include colic surgery, glaucoma, and adoption services.

Colic Surgery for Older Horses
Geriatric horses have lower survival rates than younger horses following exploratory colic surgery, but a year later there’s no significant difference in survival rates between the age groups, report Florida equine veterinarians in a new study. Most horses discharged from an equine hospital after surgery were still alive one year later, regardless of age.

As age is often a consideration when deciding whether to proceed with colic surgery, Drs. Kathryn Krista and Leann Kuebelbeck collected data on both geriatric (20 years of age or older) and younger horses that had colic surgery at the Surgi-Care Center for Horses in Brandon, Fla.

“The survival rate at the time of hospital discharge for geriatric horses was 50%, significantly lower than the 72% survival rate in nongeriatric horses,” said Krista. “This difference in survival rates was thought to be due to the higher number of (older) horses euthanized during surgery.”

While this finding is not particularly encouraging for owners of geriatric horses, additional data generated by this study are not as bleak.

“Of the horses that survive surgery and recover from general anesthesia, survival rates in geriatric and nongeriatric horses were 82% and 89%, respectively,” said Krista, who went on to explain that the difference was not significant and that no difference in survival rates was noted one year after surgery. “The information obtained from this study may serve as an important reference for veterinarians to share with the owners of geriatric horses as they are trying to make the difficult decision about whether to pursue surgery as treatment for colic,” she said.

Alterations in the formation and drainage of aqueous humor (clear eye fluid) can cause glaucoma in the horse, a rare condition that’s characterized by increased pressure within the eye. This pressure potentially interrupts normal function of the retina and optic nerve, causing loss of vision. Dr. Dennis Brooks, professor of ophthalmology at the University of Florida College of Veterinary Medicine, discussed this issue at the recent AAEP Focus on Ophthalmology meeting.

In glaucoma cases the owner generally notices corneal edema, which appears as a bluish tinting to the cornea, along with dilation of the affected eye. Unlike in humans and small animals, glaucoma in horses does not seem to cause pain, but blindness stemming from atrophy (partial or complete wasting away) of the optic nerve can often develop.

The veterinarian treating a horse with glaucoma often focuses on keeping intraocular pressure (IOP) at a level to maintain retinal and optic nerve health. Controlling the production of aqueous humor and increasing its outflow are crucial.

Surgical options, including laser surgery, implants, and removal of the ciliary body (the part of the eye responsible for production of aqueous humor), might be viable when medical therapy is not enough to control elevated IOP.

Adoption Service
In a little more than a year, more than 230 Thoroughbreds and Standardbreds have found new homes via free listings on’s adoption service.

The service is a free bulletin board where owners can list any horse offered free to a good home. It also features resources on horse adoption. Interested individuals contact the horse’s owner directly. More than 150 horses are currently available, including experienced riding horses, new prospects, and pasture pals.

To list a horse, see

Excerpted from The Horse: Your Guide to Equine Health Care. Free weekly newsletters at