Who ever heard of shoeing a horse with plywood, screws, and a drill, especially a laminitic horse? It might sound like the worst kind of backyard farriery, but this method is finding favor with a growing number of veterinarians and farriers. The procedure has been presented twice at the American Association of Equine Practitioners Convention, three times at the International Hoof Care Summit, United Kingdom, Germany, Ireland, the International Laminitis Symposium and it was published in the April 2010 Laminitis issue of Veterinary Clinics of North America-Equine Practice.
They aren't high-performance shoes by any means, but these wooden clogs seem to provide the healing environment that many damaged feet need. "If sole impression material, screws, and cordless drills were readily available in 1887, this shoe design (suggested in Magner's Classic Encyclopedia of the Horse, 1887) and technique possibly would be standard procedure in the therapeutic treatment of laminitis," says Micheal Steward, DVM, of Shawnee, Okla., inventor of the clogs.
The Steward clog in action.
What Does a Horse Clog Look Like?
There are up to four components of the clog shoeing system: Plywood, deck screws, sole impression material, and glue or casting tape for further anchoring the wall to the shoe, if needed. These materials are easy to find and relatively inexpensive, which is one of the reasons why Steward came up with the concept. In his Oklahoma practice, he has had many clients come to him with laminitic horses, but not a lot of money to treat them.
The "shoe" consists of layers of plywood or plywood / ethylene vinyl acetate bonded together, beveled (with an angled ground surface) at both the heel and toe, with a flat surface ground surface allowing hoof stability. These three planes of the shoe allow the horse to shift the weight on his feet to nearly any angle if he's standing on soft ground. The flat ground surface also allows the horse to stabilize his hoof angle in one spot better than a curved shoe on hard surfaces.
The wood itself has advantages over metal shoes, according to Steward. "The most damaging / painful force to the hoof is the high-frequency impact forces (analogous to hammer hits), which occur during hoof landing" he says. "A natural product (wood) absorbs more shock than conventional metal shoes."
Also, the wood can be filed to shape or worn by the horse to a more comfortable shape much more easily than metal. All of this means a more comfortable horse--which is both the immediate and ultimate goal.
Laminitis: A Bloody Problem
Whatever the causative insult, laminitis often results in a great deal of damage to the foot's lamellae and vascular system. This compromises blood flow to the various hoof tissues when they can least afford it--when damaged, they need more nutrients from the bloodstream, not less.
One problem with blood flow in the damaged foot is due to the anatomy of the walls of the veins in the foot- they are extremely muscular, says Steward. "Every founder case exhibits varying degrees of venospasm (displayed with diagnostic venograms, in which contrast dye is injected into a blood vessel so the hoof's blood vessels can be seen on a radiograph)," he says.
In other words, the stressed vessels have contracted similar to a muscle spasm, so little blood can get through. This spasmodic contraction is under the control of a variety of chemicals and might lead to permanent damage to the vessels within the foot.
So how do you relieve muscle spasm and restore blood flow in a foot with damaged blood vessels? How might you relieve a muscle spasm in your own body? With massage, of course.
Massaging the Foot--Internally
"The full roller motion horseshoe (clog) is designed to provide CPR to the damaged hemodynamic (circulatory) system in the hoof," says Steward.
With its small, flat center surface and heel/toe rocker, the clog appears much less stable than a flat shoe. But that very instability is what allows the horse to continually readjust the angles of his feet, redistributing the load on the inner structures and thus massaging them. This may help cramped blood vessels relax and the increased mobility of the hoof encourages increased blood flow within the foot.
Sole impression material is used to redistribute the solar load to less painful areas of the bottom of the hoof. Primarily the palmar (back) of the hoof is filled with the conformable material (including the sulci, or grooves in the center of the frog and on each side). This unloads the damaged toe solar area allowing the compressed solar blood vessels to regenerate.
"One of the desirable results of correctly installed impression material is the apparent increase in solar blood flow as evidenced, oftentimes, by the tremendous growth of healthy sole," Steward notes. This sole growth is important to support the coffin bone and help correct rotation, if it has occurred. Its progress is measured by lateral radiographs taken each time the horse is shod; Steward estimates that sole growth doubles in most cases within 30 days of the clog's application.
Anything that compromises the circulatory system of the foot for a period of time (i.e., laminitis, or poor hoof balance that places focal areas of pressure on some areas so the blood flow is compromised) can result in permanent damage to starved tissues. The damaged vascular supply cannot provide all the nutrients needed for proper hoof growth, thus the condition often becomes a vicious cycle--damage or pressure hinders blood flow, which hinders healing and hoof growth, then poor healing or growth means the blood flow problem gets worse, further hampering healing. Rotation of the coffin bone (P3) is a good example. When the toe of P3 rotates down toward the sole, it crushes the blood supply beneath it. Sole growth in this area is poor due to the damage and decreased blood supply, and poor shock absorption from the thin sole increases the chance of further damage, when good sole growth here is sorely (pardon the pun) needed to reestablish proper P3 position.
Some problems like laminitis can be hard to prevent, but others like poor balance are not as tough to avoid. Keeping your horse's feet properly trimmed and balanced will stave off some of them. It's such an old adage--An ounce of prevention is worth a pound of cure--but it is still very true.
Think of standing around all day at a horse show--you will definitely notice where your shoes don't fit perfectly by the end of the day. But if your horse's previously healthy feet are improperly balanced and his hooves' blood vessels are compromised, he has to wait six to eight weeks for the next trim before he gets any relief. A lot of damage can occur in that time frame, let alone across several poor shoeings. And this doesn't even begin to compare to the effects of poor shoeing on a damaged foot that must have an ideal environment to heal.
You've always known that properly balanced feet were essential for health and performance, and proper blood flow is one of the biggest reasons why.
Protecting and Stabilizing the Foot
Increasing blood flow is important, but so is supporting and protecting the damaged hoof structures.
"The laminitic foot needs to be thought of as a broken bone in need of stabilization until the hoof can reattach the bone to the hoof capsule," says Steward. "The attachment is enhanced by the artificial stabilization a correctly applied therapeutic shoe will provide."
A therapeutic shoe for laminitis should reduce the forces spreading apart the "bone fragments" of our broken bone analogy--the hoof wall and coffin bone. Normally, the laminae are more than equal to the task of supporting the coffin bone within the hoof, but laminitis destroys their integrity and thereby their strength.
So how do we reduce the forces tearing the hoof apart? There are two major forces pulling the coffin bone away from the hoof wall: the weight of the horse primarily transferred through the deep digital flexor tendon (DDFT) that attaches to the bottom of the coffin bone and flexes the leg, and the force of the ground against the toe as the hoof breaks over during locomotion. Both of these forces are reduced by moving breakover toward the heels with the rockered toe on the clog.
"The facilitating or increasing of blood and lymphatic flow (as a result of using the sole impression material), combined with the enhancement of mobility (via the full roller motion shoe design) and weight redistribution, probably account for the immediate pain relief (with the clog shoeing system)," he adds. "Most of the time one should expect immediate and ongoing pain relief as evidenced by the horse's relaxed gestures and body language, more normal stance and gaits, and increased voluntary locomotion. The degree of pain relief varies from case to case, but relief should be evident in every case; otherwise, take the shoes off and rethink and redo the application."
Applying the Clogs
Steward says the clogs themselves are only part of the solution--they are tools, and just like any tools they need to be used correctly to achieve the desired effect. The key is reading the horse's body language to see how much pain he is in and what it takes to relieve it.
The shoeing process starts with the veterinarian and farrier watching the horse walk, conducting a physical examination, and taking radiographs to visualize the positions and conditions of the inner foot structures. Then the foot is trimmed carefully and correctly, any abscesses are cleaned out and packed, and the excess toe wall common to chronically laminitic cases is rasped off to realign the wall with the coffin bone.
"This allows the new hoof growth that begins at the coronary band to not follow the template of the forwardly displaced toe," explains Steward. "A hoof with more normal-appearing conformation will grow in a more normal fashion and will function in a more normal way."
This cutaway view of a hoof with a clog and impression material packed under the sole shows the entire system at work.
Next, the shoe is fitted by having the horse stand on the shoes (held on by two screws) and reading his comfort level. Then sole impression material is packed into the foot, taking care to unload sore spots by thinning the impression material or cutting it out. The horse is asked to stand on the foot while the impression material is setting up to better shape it, and he should appear more comfortable with it in place.
Then it's time to screw the shoe to the foot with 1 5/8-inch deck or stainless screws (1-inch screws for single-layer shoes). "I think the screw is a better system for foundered horses (than shoe nails) because it holds the wall where you put it," opines Steward. He generally uses two to three screws through the wall on each side, and places additional screws against the outside of the heel walls to further stabilize the foot. Glue, wraps, and/or fiberglass casting can provide additional stability.
"We hardly ever tranquilize or block, because we want to read the horse. He's the one who tells you what to do," states Steward. "If you don't ask the horse, with any system, you don't get the results you want. If he wants to stand on his toe, let him. Be not a horse whisperer, be a horse listener. This is all experimental."
Resets are done every four to six weeks on most horses. Anti-inflammatory medications to control pain, inflammation, and swelling are also used to facilitate healing.
Other Uses for Clogs
Laminitis isn't the only hoof problem that clogs can help--any condition in which blood vessels are compromised or the toe is stressed can be improved with these shoes, says Steward. These include heel pain, navicular disease, and white line disease. One can see additional benefit from the rockered shape of the clogs in horses with injured flexor tendons, arthritic knees, ringbone, or other joint dysfunction, he adds.
Also, the clogs can be screwed to the bottom of a fiberglass cast to reduce the forces on the cast, much like a walking cast or boot on a human.
Laminitis treatment will never be 100% because of the damage some cases have sustained, cautions Steward. "Economic and humane concerns often dictate euthanasia," he says. "The shoe works on all horses to help them walk easier, but let's say pain is on a scale of 1-100. Let's say a horse is at 100 and the shoe lowers him to a 76. He's still in a lot of pain, so the humane thing to do is to not go on with this horse. He's lost so much that the foot just can't recover."
On a less drastic note, there's also a concern of helping the horse feel a little too good, at least at first. "If you kill enough pain that they feel great, they run around do too much, and get very sore," Steward warns. "Restrict their area to run around so they can't hurt themselves."
Yet another concern is abscesses, which are localized pockets of infected and/or dead tissue and pus. They're unfortunately common in laminitic or otherwise damaged feet.
"Abscesses are a problem in many cases due to the damaged blood supply leading to dying areas of the coffin bone. These 'sequestra' need to be expelled from the hoof and (the abscess) often will erupt as the horse becomes more mobile," Steward says. "Some of these horses, you put on the clogs and they get along great, and about a month later here come the abscesses."
Clog Success Stories
Steward claims a great deal of success with using this shoeing system to treat laminitis of two months to six years duration, as well as other problems. He and his farrier apply around 1,000 sets of clogs per year, and he says many cases are able to return to regular shoeing methods after two or three resets. These include recoveries from mild problems and wildly successful stories, such as a barrel horse named Buster Brown competing in the 2006 International Youth Rodeo Finals. He was nearly put down after a botched nerve block resulted in a host of problems (coffin bone disintegration, ringbone, and a large avulsion or separated fracture). Then he was treated with the clogs.
"Now all you can hear is his five-year-old rider screaming as the horse blasts around the barrels," laughs Steward.
The bottom line is that, "The full roller motion shoe, solid base shoe and properly placed sole impression material can provide an affordable, efficient, and highly effective treatment to return many cases of laminitis to a satisfactory degree of soundness," says Steward. "These horses don't have to die."
Steward, Micheal. How to Apply the Therapeutic "Rocking Horseshoe" (Also Known as the Steward Clog) to Enhance the Healing of the Chronic Laminitic (Foundered) Hoof As Well As Other Hoof Conditions and Diseases. Proceedings of the International Hoof Care Summit 2005: 64-80.
Steward, Micheal. How to Construct and Apply Atraumatic Therapeutic Shoes to Treat Acute or Chronic Laminitis in the Horse. Proceedings of the American Association of Equine Practitioners, 2003: 337-346.
About the Author
Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.
POLL: Horse Height