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Soring (Part 4): Turning Up The Heat On Soring
The use of new technology is going to make it easier to detect soring and pressure shoeing violations during show inspections.
Whether soring is less of a concern than it used to be pretty much depends on whom you are talking with. But many of the folks who maintain that soring and pressure shoeing are still major concerns in the Tennessee Walking Horse (TWH) industry and with several other breeds, readily admit that the practice has gotten much more sophisticated and tougher for inspectors to identify.
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With limitations in the current physical examinations that are used to identify soring concerns, several new scientific technologies are being evaluated as to the role they might play in helping identify soring and pressure shoeing violations.
Rachel Cezar, a veterinarian and Horse Protection Coordinator with the U.S. Department of Agriculture (USDA) says the government agency is evaluating several new technologies to make it easier to identify soring concerns. This includes the use of themography, digital radiography, pressure gauge response to pain, new biofeedback developments and chemically evaluating swabs taken during inspections from the pastern area for foreign substances to identify soring concerns.
“As an example, foreign substances are prohibited from being applied above the hoof except for lubricants and oils that meet certain restrictions,” she says. “We’ve found even sunscreen can block the results from thermography when used to identify soring.”
Cezar’s goal is to find new ways to solve the soring and pressure shoeing concerns. “By all of us working together, my hope is that eventually the industry will self-police itself,” she says.
New Techniques Needed
Stephen O’Grady says relying on a combination of thermography and radiology could go a long way toward eliminating the soring problem. But the equine veterinarian from Northern Virginia Equine in Marshall, Va., says these techniques need to be used along with a thorough physical examination of the hoof and leg in evaluating soring concerns.
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The black arrows show the vertical “hot streaks.” |
He says the most important tool needed in doing a physical examination is a hoof tester. To look for soring concerns, O’Grady says a thorough physical examination by inspectors should evaluate the biomechanics of the hoof, hoof capsule distortion, sole thickness, the coronary band and digital pulse.
With interest growing in the use of more sophisticated techniques for determining soring and pressure shoeing, here’s a rundown on several techniques that are being evaluated by the USDA.
Thermography Looks Promising
Tracy Turner says thermography can measure local circulation, blood flow and local tissue metabolism and has proven valuable in diagnosing lameness.
“The actual thermal pattern is the key, much more so than the actual temperature,” says the equine veterinarian with Anoka Equine Veterinary Services in Elk River, Minn., who has worked with thermography in horses for three decades and made the images shown here.
“The leg should be relatively cold except for the coronary band and the laminar corium,” he says. “Between the bulbs of the heel is the warmest area.”
Turner says a diagnosis is not being made with thermography, but it finds areas that need to be checked further. “It can detect as much as 10 times the amount of heat that can be found with palpation,” he says. “It can be used to detect inflammation in hot spots and even cold spots where swelling in the hoof or foot can reduce blood circulation.”
At a mock TWH show last year, Turner used thermography on 15 actively shown TWH suspected of having soring problems. Among these horses, thermography evaluating indicated that one was normal, five had an abnormal pastern, three had abnormal hooves, five had both abnormal hooves and pasterns and one horse had an abnormal cannon bone.
Upon further inspection with palpation or digital radiography, 11 of the horses were confirmed as abnormal.
“I see the use of thermography as a big boost for inspectors at shows,” says Martha Day, the director of Designated Qualified Persons (DQA) for the National Walking Horse Association at Pleasant View, Tenn.
“I believe it could clean up this industry practically overnight. If thermography showed me a reason to pull a shoe during an inspection, I’m quite sure I would find a soring problem. But it will take plenty of training among the inspectors to make it work effectively.”
Turner says 2008 was a hands-on training year for thermography among the USDA staffers. The inspectors went through mandatory thermography training followed by a year of using the instrument and getting better acquainted with the technology.
“During 2009, USDA veterinarians will go through additional thermography training and the instrument will be used during the 2009 show season,” says Turner. “My understanding is that thermography will be a screening tool to raise suspicion for the inspectors. Final determination if a soring violation has occurred will still be with the USDA inspector.”
Pressure Algometry
Pressure algometry relies on the use of a gauge to judge a horse’s response to pain. This device can be used to measure the amount of increased mechanical pressure within the pastern region that occurs with soring, says Kevin Haussler.
The Colorado State University researcher says the technique measures the amount of force applied to a horse’s skin. It offers a more consistent means of identifying sored areas compared with having the inspector palpate the leg.
To establish, normal pressure thresholds, Haussler used an algometer to examine 25 TWH that had previously passed a routine Horse Protection Act (HPA) inspection for soring. These horses were evaluated for pain in the dorsal, lateral, medial and palmar areas of the pastern that are typically painful in sored horses.
His studies determined that application of thumb pressure, which flattens the flesh and blanches the nail as called for under current HPA regulations, equals 0.4 to 0.6 kg/cm of pressure. Most importantly, he found the horses in this study could tolerate 30 to 50 times more pressure than that amount in the pastern region without flinching.
Haussler says additional pressure algometry research needs to evaluate the impact of weighted shoes, stacked or wedged pads, chains and pressure shoeing.
“Pain does not stay in one place with a sored horse,” says Haussler. “It can move to other areas, which means you need to look at hoof conformation such as an irregular angles and long toes. With posture and locomotion concerns, you need to look at stance, gait and the rider.
“We can identify pain in horses, but we need to evaluate whether we can determine pain in the entire horse due to soring. We also need to be able to identify the presence of topical antiseptics and joint injections.”
Pastern, Coronet Band Swabbing
The USDA is also evaluating “chemical sniffing” as a way to check for foreign substances in or on a horse’s legs. During inspections, the front pasterns and coronet band are wiped with swabs. These swabs are then sent to a USDA laboratory for gas chromatography and mass spectrometry analysis for chemical compounds with results in 2 to 4 weeks.
In field tests at 14 TWH shows, USDA inspectors swabbed the legs of 353 randomly selected horses. Nearly 50% tested positive for foreign substances that included fuel components, irritants and even anesthetics used to temporarily mask sored legs.
Digital Radiography
Use of digital radiography offers both speed and convenience in providing detailed on-site imaging. It would be extremely useful in identifying objects inserted between the pad and hoof with pressure shoeing.
While the naked eye can see 256 shades of gray, Turner says digital radiography can see 4,000 different shades of gray, making it extremely valuable in detecting density differences within the foot or leg due to soring concerns.
Measuring Skin Response To Pain
A new technology called PainTrace is a noninvasive method of measuring skin response to pain. Similar to biofeedback devices used with humans, these units from Biographs, LLC, rely on electrode sensors placed on the animal to measure the skin’s natural electric charge. The manufacturer claims a 1-minute test will document moderate or severe pain lasting more than 20 minutes that might be the result of pressure shoeing or soring.
Nothing Comes Cheap
The cost of a thermography camera ranges from $8,000 to $20,000. Skin pressure devices to measure pain cost $3,600 and pressure algometers are priced at around $175.
It’s tough to get research and equipment dollars to investigate the pressure shoeing and soring problem, as this kind of funding normally comes from the involved industry. But with some folks maintaining that soring no longer exists, the chances of getting needed dollars from industry to help solve the problem is close to zero.
Even so, the use of more sophisticated equipment and techniques is certainly going to be part of future shoeing and pressure shoeing inspections.
