Canker as unpleasant as it sounds
by Hannah Beers
Canker is a chronic infection of the frog. The frog is the soft, cushioned area at the rear of the sole of the horse’s hoof.
The infection is often anaerobic, meaning it doesn’t require oxygen to survive. As the body’s natural immune defense tries to ward off the infection, a white irregular tissue develops. The foot also produces a white smelly discharge, and the horse has difficulty walking because its feet are sore.
Dr. Erica Secor is completing a three-year residency program in equine surgery at the University of Illinois College of Veterinary Medicine. She explains that canker “is the horseman’s term for proliferative pododermatitis.”
Dr. Secor has a particular interest in horse hoof issues and care. She trained as a farrier before becoming a veterinarian. “The farrier may also notice that the feet will bleed easily and the horse may be less tolerant of the shoeing process because of pain from the infection,” Dr. Secor explains.
Draft horses most commonly suffer from canker, but veterinarians aren’t sure why.
“It could be because draft horses have large feet with deep crevices that are more susceptible to infection,” Dr. Secor adds. “Or they may have a genetic predisposition to this infection, or it could be a combination of these reasons.”
Horses exposed to a wet environment, such as damp bedding in a stall, are more likely to develop canker.
“Oral antibiotics don’t really touch proliferative pododermatitis because when giving a medication like that orally, not enough of it gets to the foot,” says Dr. Secor. “The mainstay of treatment is topical medications, such as benzoyl peroxide… This works well to dry out tissue.”
Veterinarians may also try surgical debridement, the process of cutting away the abnormal, infected tissue using a scalpel blade.
Dr. Secor says even when a significant amount of the frog is removed the horse usually adjusts well. The frog grows back within six months.
After the surgical debridement procedure, the horse’s hooves are protected with a pad and bandages. A hospital plate, which is a piece of metal cut to the size and shape of the horse’s hoof, is bolted onto the horse’s shoe. It keeps the bandages and medication in place.
Canker is often chronic. Relapses may occur after treatment. The best way to prevent canker is to keep bedding clean and dry. The owner should pick out the horse’s feet often.
“If you notice that your horse is sensitive to having its feet touched, has discharge, or has strange-looking tissue, call your veterinarian immediately,” advises Dr. Secor.
“The home remedies promoted on the Internet don’t often work and just allow the condition to worsen. Canker is most easily treated when it is caught early.”