The Auburn Study: Thermography in Diagnosis of Inflammatory Processes in Horses in Response to Various Chemical and Physical Factors
Thanks, American Horse Defense Fund, for posting this study!
The Auburn Study is well known throughout the industry. Unfortunately, it’s pretty obvious that most people have never even read it, or they would know what it was really done for. The opening sentence states: "To study the effects of acute and chronic inflammatory responses of the horse’s thoracic (front) and pelvic (hind) limbs, several studies were done over a seven year period at the School of Veterinary Medicine, Auburn University, Alabama." It says nothing about studying the effects of pads in this sentence at all. However, while they don't actually study the effects of pads, the conclusions they make after doing the work ends up showing us that pads are bad, and that they can cause problems for the horse.*
The study was done in a total of 18 phases. The phases can be read on the study itself, but overall, there is absolutely nothing in this study that talks about the pads themselves. The study itself is titled Thermography in Diagnosis of Inflammatory Processes in Horses in Response to Various Chemical and Physical Factors. This means that what they did was study the effects of using chemical irritants and different sized chains using thermography. Thermography itself is a pretty neat science. Here’s a great definition on how it works from Wikipedia.
Infrared thermography, thermal imaging, and thermal video are examples of infrared imaging science. Thermal imaging cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 9000–14,000 nanometers or 9–14 µm) and produce images of that radiation, called thermograms. Since infrared radiation is emitted by all objects above absolute zero according to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become easily visible against the environment, day or night. As a result, thermography is particularly useful to military and other users of surveillance cameras.
Inflammation in a horse’s limbs can easily be detected using a thermal imaging camera. So what the vets at the Auburn Study did was take a base reading of the horse at rest to show the level of heat that horse’s legs produce. Then they ran separate experiments with different types of chemicals and different chain weights to the pasterns and then worked each horse for a certain amount of time. Then they did new scans with the camera and recorded the results.
The results showed that chemical soring and pressure shoeing do cause pain, that chains combined with chemical soring does cause pain, and that 10 oz chains or heavier without chemicals caused pain. This study also pointed out that 2, 4 and 6 oz chains without chemical soring did not cause any detectible pain or tissue damage, with the exception "to some loss of hair from 6 oz. chains in the pastern areas." So hair loss is possible with 6 oz chains. Since this study, there is a rule that only chains up to 6 ozs are allowed in the ring, but I certainly don't see DQPs weighing chains when horses are being inspected.
One part of the study is particularly notable. This is Phase XV, as posted below.
Phase XV. Preliminary Studies to Evaluate the Effects of Change in the Heel to Toe Ratio
The objectives of this study were to determine if deviation of hoof angle will alter the gait of Tennessee Walking Horses and to determine if tendonitis or other inflammation were caused by deviation of hoof angle. Two horses, # 22 and # 23 were placed under observation on 4/9/81 and monitored before and after 15-20 minutes of exercise with thermography, pressure device, Micron, rectal thermometer and visually by rider, technician and veterinarian. Horse # 22 was shod from ‘barefoot status to wedges, pads and shoes on 4/13. Horse # 23 had been shod similarly before 4/9/81. On 4/29 the heels of both horses were raised 8 degrees, before exercise and monitoring. On 5/11 the heels were dropped 12 degrees by removing wedges and the horses exercised and monitored. Horses were then exercised and monitored on 10 separate days during the period of 5/12 - 6/1. No action devices or chemicals were applied to the feet or legs during the study.
Thermography study suggests that shoeing of the forefeet in pads and wedges from a barefoot status (horse # 20) causes a 1—2 degree rise in temperature in the superficial and deep flexor tendon area.
Similarly, inflammation in this area was observed on thermography when the angle of the hoof was raised or lowered (both horses). When the heels were lowered on 5/11 and observed until 6/1 there was a gradual decrease of inflammation in the f1exor tendon area.
Pressure readings taken at the usual 6 points on the foot fluctuated to a minor degree, reaching their lowest levels 2 days after the heels were elevated 8 degrees in both horses. Raising the heels 8 degrees caused both horses to stumble and tire easily. They did not regain a sound gait for about 7 days. When the heels were dropped 12 degrees the horses gaited more soundly although there was swelling in the flexor tendons for about 7 days. Raising or lowering the heels of Tennessee Walking Horses and shoeing one with wedges and pads from barefoot status causes thermal patterns in the flexor tendon area that can be distinguished on thermography. These changes cause less fluctuation in pressure readings than the use of action
devices or chemicals. Inflammation subsides about one week after the heels are raised or lowered 8 and 12 degrees respectively. Raising the heel causes a more observable change in the horses’ gait than lowering the heel after it has been raised.
If anything, this part shows that pads ARE bad for the horse. When raising the heel, it caused swelling in the flexor tendons. This can lead to tendonitis, which is a bowed tendon, which is very painful and takes a long time to heal. And over time, a bowed tendon that is not treated can lead to damage and tearing of the fibers of the tendon itself. Click here for more information. If anything, this should show us that horses should be off pads when he’s not being shown, and this means off pads after each show, to prevent the horse from getting tendonitis in the long run. If the horse shows this swelling after 7 days, imagine what kind of swelling could be present after wearing stacks for months on end during show season.
Plus, raising the heel in general caused the horses to “stumble and tire easily,” and "they did not regain a sound gait for about 7 days." Perhaps it’s because the tendons were swollen?
February 19, 1982
Dear Dr. Schwindaman:
We have yet to carry out the formal steps to determine the effects of built-up pads on Tennessee Walking Horses. Over the years, however, we have experienced what the group considers a high rate of thrush in the horses we have shod with pads and used in tests. Although it is not readily apparent on clinical observation we have observed with thermovision varying degrees of abnormal inflammation on the posterior aspect of the metacarpal area where the flexor bundle is located. This usually occurs the day after a horse has been freshly shod, whether or not he is exercised daily, and lasts from a few days to two weeks.
Attached are some questions we asked of our farrier and four clinic veterinarians who devote their professional time almost exclusively to equines. They all answered 'yes' to the first two questions and suggested sheared heels, quarter cracks, and laminitis as other abnormalities of the forefeet of Tennessee Walking Horses shod with conventional pads. They all answered 'yes' to the fourth question, giving their reason that they could not adequately examine the feet unless the sole was exposed.
R.S. Sharman, DVM
1. Do you associate , from your observation, increased incidence of thrush with pads covering the sole of horses hooves? [YES]
2. Contracted Heels? [YES]
3. Other abnormalities? [YES - sheared heels, quarter cracks and laminitis]
4. Would you consider it necessary to remove pads and shoes from a horse to do an adequate foot examination? Why? [YES - The foot cannot be adequately examined without the sole exposed.]
Clearly, even without doing a specific study on the effects of pads,* the Auburn Study has a lot of evidence that pads are not good for the TWH. Hopefully we'll see more evidence in the future of the damage pads do. However, I don't think the industry can hinge their hopes that pads are okay by this study.
*Added for clarification 8/11/11