Rundown on horse health

Six horses at the School of Veterinary Medicine have been getting a new high-tech workout on, what else, a horse
treadmill. Barbara Smith, a veterinarian and UC Davis postdoctorate researcher, is using the treadmill in a yearlong study looking at the effects of exercise on cartilage transplants in horses.

Horses who have had cartilage transplanted from one hind stifle, or knee joint, to the other are allowed to recover for two months. Smith then starts them on an exercise program using the treadmill to see how quickly they regain movement and flexibility in these joints.

"We gradually increased the time and speed during the last 89 months," says Smith. Like athletes in rehabilitation, the horses exercise on a schedule--three days a week for 1013 minutes. The first 10 minutes are spent at a comfortable trot until the speed picks up; then the horses run at a gallop for three minutes, reaching a pace of approximately 130 strides per minute.

So how does Smith get a horse to run on a machine? She begins by walking the horse onto the treadmill while it operates at a very slow rate. She holds a rope attached to one side of the horse's harness, while an assistant holds a rope attached to the other side. Sometimes a horse shifts its attention and forgets to walk or trot and comes off the treadmill backward, but none have been hurt.

Although the treadmill was initially designed for research purposes, it has been used for clinical applications as well. Racehorse trainers and private owners increasingly seek out the treadmill as a diagnostic tool in determining their horses' ailments and for rehabilitating horses after orthoscopic surgery.

Veterinarians and trainers also use the treadmill to assess respiratory and heart problems that are best diagnosed while a horse is running. Electrocardiographs attached to a horse's chest measure heart rate as the horse runs at various speeds.

To assess respiratory problems, an endoscope--a small tube with a camera attached--is passed through a horse's nasal passage into the larynx to provide a video of its movements. A common respiratory ailment, left laryngeal hemiplegia, which causes semi-paralysis on the left side of the larynx, is indicated by reduced movement on the left side of the larynx of a heavily breathing horse.

The treadmill is also helpful in identifying muscular-skeletal problems in a horse, such as lameness and muscle soreness. Some muscle problems may not be evident at a slow walk, but become more visible when a horse is pushed to run.

Smith says it is still too early to determine the exact results of her study, but using the treadmill for rehabilitation will benefit all horses with cartilage abnormalities, whether they are the result of developmental problems or stress and strain.

"The horses get a good workout here," Smith says. In fact, they seem to enjoy it.

Photo by Markus Pfitzner/UC Davis Creative Communications Services