If Your Horse's Feet Could Talk

EDITOR'S NOTE: This article gives horse owners a glimpse into the methods used by one experienced veterinarian to monitor the feet of his clients' horses. Your veterinarian might have developed his/her own special way to follow the normal/abnormal foot, or you might be looking for a place to start a program to track your horse's foot health.

It has been said that more than half of all lameness in horses is the result of pain within the hoof or is associated with the consequences of improper hoof wear. When you consider the size of a horse's foot in relation to his body mass, it seems incredible how much weight and concussion this structure can withstand. The average horse supports almost five times as much weight per square inch of foot surface area as a human and can move almost four times faster!

Human athletes are very particular about footwear that is not only very specific to their sport or application, but also that fits the individual athlete perfectly. Any defect in the shoe, or how it fits, is quickly reported by the athlete to the coach or trainer so an immediate remedy can be sought.

Now imagine the equine athlete; he/she cannot speak and describe pain or discomfort. The owner's or trainer's ability to detect a problem is a function of experience (seeing other lame or painful horses) and ability to observe the horse during movement. When you consider the ability of a human to detect problems, it must also be remembered that this can only be done accurately at the walk and slow trot. After the horse begins to move faster than about seven miles per hour, the images begin to blur and changes in foot flight become more difficult to detect. What this means is that typically for lameness to be noticed, it must be evident at the walk or slow trot.

How many horse's principal gaits of occupation are the walk and slow trot only? Is it possible that a horse would appear sound at the walk and slow trot, yet have a source of pain in his foot or body that would diminish his performance at a faster gait? Of course!

These issues face the modern horse owner and veterinarian in their pursuit of husbandry and training techniques that maximize the athletic potential of the horse and provide the highest quality of life during his athletic career.

In the last 10 years, tremendous advances have been made in our ability to detect causes of subclinical lameness. For many areas of equine athletics and exercise physiology, man has developed tools with which he can obtain information that previously would only have been available if the horse could describe how he felt. Most of these advances have come in two areas--the application of physiologic imaging tools such as nuclear scintigraphy and thermography, and the use of high-tech tools such as high-speed treadmills, videography, endoscopy, and musculoskeletal structural analysis software.

Many training centers and veterinary facilities now offer comprehensive analysis programs that allow for the early identification and treatment of health problems or potential areas of weakness that are capable of affecting the horse's athletic performance and well-being. Here are some of the tools you can expect to see in use if your horse's foot care is being evaluated.

Clinical Evaluation

This really isn't new, but without it all of the technology in the world would have little meaning in improving the performance of your horse. It all begins with a comprehensive evaluation of your horse in-hand, during movement in-hand, and during the performance of his principal occupation. From this, opinions are made and questions are posed which the remaining aspects of the examination address.

Physiologic Imaging

These imaging tools, primarily thermography and nuclear scintigraphy, produce a diagnostic image by measuring some metabolic activity of the body. In the case of thermography, the images are generally of changes in blood flow. Since blood is the hottest substance in the body, and its flow will change with pain and inflammation, the real-time thermal imaging camera is a very quick, non-invasive method of determining where abnormalities exist in the leg and foot (see examples above).

Nuclear scintigraphy, or bone scanning, is also a very accurate way to determine inflammation in bones and joints that is associated with lameness and abnormal foot wear. This imaging tool measures the radiation (gamma rays) from a radioactive isotope bound to a molecule that is normally present in the tissue you want to study. In the case of bone, the isotope technicium is bound to a phosphate ion (bone is primarily made up of a protein matrix of calcium and phosphorus), which then travels through the blood stream to the bones.

In areas where the bone is more metabolically active, more of the radioactive phosphorus will be extracted from the blood and deposited in the bone. This allows for an image to be acquired that clearly demonstrates the area of inflamed bone. The images at left are the bone scans of a horse with pedal osteitis (inflammation and demineralization of the coffin bone). The dark areas are the regions of highest radiation, which correspond to the areas of inflammation in the coffin bones of this horse.

See diagnostic foot images here

High-Speed Analysis

High-speed treadmills, combined with videography, allow faster gaits such as the trot, canter, and gallop to be recorded and played back in slow motion to help us better understand a horse's foot flight and landing. Areas of friction between the foot and the treadmill surface also can be identified, which can yield useful information about how the foot is landing and breaking over.

Computer-Aided Diagnostics

Computer software has been developed that brings a whole new realm of objective data to the maintenance and repair of damaged horse hooves. This computer program was developed by robotics engineers who were also avid horsemen. The program incorporates a series of measurements taken from two radiographs (X rays) and three photographs of each foot. Once entered into the computer, several measurements are made and compared to a database of other horses of similar breed or occupation.

With this information, very precise changes can be made by the farrier to correct any imbalances that might exist in the foot creating lameness, or potentially limiting performance. These images also serve as a record to monitor the foot. Because the images are stored on the computer, they are easily printed out or e-mailed so as the horse changes locations and farriers, a record of foot care can travel with him.

New Hope for the Future

With the incorporation of the tools mentioned in this article for the examination of the horse showing lameness or diminished performance, new levels of hoof care have become available. Although speech would still allow for the horse to describe his condition the best, modern technology now offers the highest level of diagnosis and treatment that has ever been available to the equine athlete.

About the Author

James K. Waldsmith, DVM

James K. Waldsmith, DVM, is the owner of Edna Valley Veterinary Medical Center, Inc., which operates The Equine Center in San Luis Obispo, Calif.

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