The Natural Hoof: A Sign of the Times
The popular image of the American "wild" horse has gone through a lot of changes in recent years. Once the epitome of the wild and free animal in a Marlboro cigarette commercial, the wild horse soon was denigrated to the enemy of the Western rancher, a competitor for forage with valuable cattle during years of drought. Then came the Bureau of Land Management years, when wild horses were rounded up and "adopted" by well-meaning owners, soon followed by the sanctuary concept, indicating that the hope for wild horses was to find areas of the country that could be set aside for them. Recently, individuals within the BLM have been accused (but not proven guilty) of corruption and illegal sale of wild horses for slaughter. Throughout, humane groups have championed the wild horse's right to exist and live as (and where) it pleases. In the winter of 1996-1997, a tribe of wild burros invaded a California town and took over gardens, lawns, and trash cans as their rightful domain, as humane groups and law enforcement officials struggled for a solution.
Wild horses have captured the public imagination in books and movies for years. But lately, wild horses have stampeded into the intellectual pursuits of many vets and farriers in America, and as far away as Australia.Will the wild horse provide a model for study of what's wrong with our domestic horses' feet?
Wild horse feet first found an audience at the 1988 convention of the American Farrier's Association in Lexington, Ky., when author/researcher Les Emery of California shared the stage with farrier/horseman Jaime Jackson of Arkansas. The two presented a mass of data about wild horse feet that glazed the eyes of the assembled farriers. Tables, charts, and graphs filled the screen. Farriers rolled their eyes. Still, the two researchers insisted that they were onto what would become the biggest story in the horse world for years to come.
Coincidentally, Emery and Jackson were followed on that 1988 stage by British farrier and lecturer David Duckett, FWCF, who laid down his theory of three-dimensional "balance" of a horse's foot. The foot has a vertical center axis, Duckett told the farriers who were accustomed to thinking of only medial-lateral and anterior-posterior balance. The external point of the axis, known from that day forth as "Duckett's Dot" was located roughly three-eighths of an inch behind the point of the frog. Following the dot vertically through the foot, it would intersect the center of P3 and the articulation of the extensor process. Careful foot trimming and shoeing would keep this point at its maximum functioning for the horse; Duckett advised judicious shortening of the distance from the point of the frog to the toe, rockering and rolling toes on feet and shoes, and generally giving the foot a simplified breakover mechanism, much like rounding corners on a block of wood to make it roll more easily.
The farrier audience loved Duckett's treatise, and Duckett's Dot soon became a household word in the farrier industry, although Duckett insists that the name is merely a catchy phrase that people find easy to remember. Looking back in old farrier texts, Duckett's Dot was plainly marked for all to see, but it had never been given a name or really explained so clearly. "The center point of the foot does not change," Duckett instructed, indicating that no matter how flared the quarters or underrun the heels, the foot could always be successfully trimmed back to a point where the "dot" would be in the center of the newly trimmed foot.
Moreover, at the same time, American farriers were struggling to understand and learn to use the heart bar shoe, another anachronism from farrier archives that had been updated and publicized by Burney Chapman, the Texas laminitis guru. Chapman lived in frustration over why his shoe found such variable success when used by others. Duckett looked at Chapman's work and told people, "The heart bar shoe works because it re-establishes the center of the foot. The horse's foot is properly balanced. It can regrow, despite the laminitis, because the tip of the heart bar shoe is right there, on Duckett's Dot." He was right. Chapman's rule of thumb, as presented to the AAEP by George Platt and Chapman in 1982, called for the point of the heart bar to end right there. Chapman had never heard of "Duckett's Dot"; he merely found the point with experience, and designed his shoes to utilize it.
Fast-forward a few years, and enter farrier Gene Ovnicek of Montana, who joined forces with Duckett for a while, then turned his attention to applying a similar common-sense, anatomy-based treatment regimen for laminitis.
While Ovnicek, a sincere, thoughtful man, worked on foundered horses with startling success rates, it would not be founder that he would become known for. Instead, in his lectures, Ovnicek took the audience on a tour of the wild horse's foot. He found no evidence of founder in wild horses. What he did find was a uniformity of hoof shape that is not duplicated in the domestic horse universe, in any breed. He found that the wild horses maintained their feet with Duckett's Dot consistently in the center of the bottom of the foot.
While Ovnicek and Duckett were puzzling over the wild horse feet with their seemingly "flat" (albeit thick) soles and protruding, leathery frogs, Jaime Jackson re-emerged, with his tables of data translated into a remarkable text called The Natural Horse, published in 1992. With the aid of simple photographs illustrating the naturally "rockered" (bevelled) toes and a co-existing bevel to the medial and lateral walls, Jackson laid a foundation for thinking of the foot as an omnidirectional base for the leg above it. The hoof wall's circumference was rounded, unlike the domestic horse's. The frog was tough, dry, and flat, a completely different structure from the domestic horse's fleshy frog.
Jackson's book, while published in a small edition, not only sold a remarkable number of copies for a hoof-related book, but also found its way onto the bookshelves of perhaps more horse owners than farriers or veterinarians. At the same time, "natural horsemanship" and holistic horse products were gaining popularity, and veterinarians began to consult on acupuncture, chiropractic adjustments, conditioning routines, and nutrition in addition to medicine to help their clients. Veterinarians found their roles changing into being advisers in maintaining the health of athletic horses, as well as caring for the sick or injured. Many embraced injectible substances, including steroids and polysulfated glycosaminoglycan (Adequan), for hock and fetlock maintenance, while others questioned why the horses were doing so poorly; how could they give advice on how a horse could be conditioned to a peak, knowing that tendons, hoof walls, and flexion joints were likely to succumb to stress or injury before that peak was ever achieved? The term "disposable horses" began as a criticism of the racing industry, then moved to the show horse world, as riders rarely returned on the same horse the following year.
Meanwhile, the farrier world went in the opposite direction of the veterinarians in the early '90s, finding a plethora of high-tech options for imperfect domestic hooves more immediately gratifying than anything "natural." Most farriers poo-poo'd Jackson's work when queried by owners, opting instead for complex rebuilding of weakened walls and heels with composites, and the use of egg-bar-heart-bar-wedged-heel shoes in titanium or aluminum. Curiously, glue-on shoes, proven to reduce stress on hoof walls, never gained the popularity many had predicted. Price factors were often given as an excuse for not using glue-on shoes; at the same time, the price of complex maintenance shoeing for show horses rose astronomically, often far exceeding the cost of the glue-on products.
Farriers felt the pressure of the horse showing and racing worlds, which require horses to keep going, no matter what. Loss of condition is a high price to pay in the show world, worse even than lost prize money or points, since a return to peak condition may be potholed with re-injury risks. Farriers were blamed for a high incidence of underrun heels in many breeds, probably caused more by training and competing more days per year on harder surfaces; the heels were collapsing not because the toes were too long, but because they were unable to support the horse over time, distance, and stress. Heel bulbs sank to the ground before farriers' eyes. Wedge pads were hailed ("We need to realign the hoof-pastern axis.") and condemned ("The best use for a wedge pad is to hold your screen door open.") in alternate lectures at farrier seminars. "To wedge or not to wedge" was a horse-by-horse dilemma for farriers, but thousands of pairs were shipped from horseshoeing supply warehouses...and still are.
Not only do horses' hooves tend to deteriorate as the show season progresses; for many horses in the 1990s, the show season was extended to include a rigorous winter circuit in Florida, Arizona, or California. Show managers did not modify arena surfaces to accommodate the over-stressed horses; even non-jumping horses like Quarter Horse pleasure and low-level dressage mounts soon were having their feet patched, bonded, and "fillered." Everywhere, arenas were described as cement-like; finally, the US Dressage Foundation initiated a series of regional awards to shows with the best footing. Hunters and jumpers have not been so lucky.
As farriers cried for help, owners kept asking more of their horses. The farriers' cries were answered by the obliging manufacturers, who looked around the world for new composites, new shock-absorbing pads, new designs for quarter crack patches. Boots to support exhausted suspensories, lasers, massage therapists, and a wide spectrum of injectible joint compounds were all aimed at the horse's fetlock, hock, pastern, and coffin joints...
Still, the horses' feet crumbled. An unnerving phenomenon called "white line disease" reared an ugly head, as farriers found hoof walls totally undermined by some sort of bacteria, fungus, or just-plain-mean organism. Add this to the usual complement of laminitis, navicular disease, and angular or flexural deformities that farriers deal with on a daily basis, and you can easily see where and how the new "professional farrier" has earned his or her stripes.
At the height of the farriers' high-tech experimentation, at one of the popular annual Bluegrass Laminitis Symposiums in Louisville, Ky., held each January, Jaime Jackson again took the stage. He described himself as an advocate of the horse, a prophet of the natural hoof. The farriers found him entertaining, amusing, and interesting on the intellectual level...but nothing in his lectures seemed relevant to them. They shook their heads and winked at one another.
It was no coincidence that Dr. Ric Redden had invited Jaime Jackson to speak, along with a Belgian researcher who talked of something called "foot mass." The next year, Gene Ovnicek shared the stage with Redden, talking about laminitis and the wild horse foot. For most farriers, the connection was too tenuous, too far-fetched. Again and again, they dismissed Ovnicek, Jackson, and Redden, who was applying the "natural foot" principles to trimming hundreds of unshod broodmares in Kentucky. "We're dealing with real horses. They live in stalls. You can't even see their feet under all the shavings. Domestic horses have nothing to do with wild horses." End of subject, with most farriers.
No one really knows how, or where, or when, but a groundswell of support for Ovnicek's "four-point trim," as promoted by Redden, took shape in 1994. Ovnicek's seminars were sold-out affairs, often including many veterinarians of the holistic persuasion. His ideas, paired with Duckett's anatomy as taught at the American Veterinary Chiropractic Association seminars, made sense. Ovnicek pointed out that wild horses living on hard ground bore their weight on their soles; the hoof wall was often rounded or not even touching the ground. The sole is calloused and the frog like a patch of leather.
Practitioners like Judith Shoemaker, DVM, in Pennsylvania, and Kim Henneman, DVM, in Utah became advocates of the natural foot. Top farriers such as eventing/dressage specialist Dean Pearson of Pennsylvania successfully started using the four-point principles on leading competition and breeding horses. When that happened, people started to pay attention.
Then something went wrong. At the 1996 Bluegrass Laminitis Symposium, farriers watched, but might not have heard, the latest recommendations from Redden and Ovnicek. Redden, ever the radical innovator, brought fish-hooked (through the sole inside the white line) nails and serious sole pressure into the equation. Ovnicek's laminitis shoe utilized sole pressure. From Canada, the 5S shoeing system used a wall-relief system to transfer the horse's weight from the wall to the sole. Farriers were confused.
From the first day of farrier school, farriers are taught that "Sole Pressure Is Bad for the Horse." Now, America's big-name lameness veterinarian was telling them that sole pressure was good? And that toes and breakover should be cut back to the first nail hole? Apparently no one was listening when Redden talked about ensuring depth of sole before proceeding, or that it was breakover that should be at the first nail hole, not the toe. Was anyone listening when he recommended putting away the GE nippers and using only a rasp on the foot, and only to round the extra wall growth down? What resulted was little short of a bloodbath on the barn floors of America. Somehow, it was all misinterpreted as trying to create a wild horse's foot on a domestic horse. Shows were missed. Horses were lamed. Others thrived.
The phone at Hoofcare & Lameness rang off the hook. The Internet glowed with alternating success and disaster stories. Traditional farriers crowed that the four-point trim was creating plenty of work for them, in patching up the feet and trying to get the horses sound again. Trainers called, shocked when they saw their horses' feet sculpted into a strange, shorter shape with the shoe set far back under the foot. Farriers, taught that the hoof capsule is like a cone, wondered why they were being asked to carve out the quarters and the toes between the "pillars," creating the now-famous four points of support. Wouldn't weakening the base of the cone make the cone prone to collapse, they asked?
In a call for reason, Hoofcare & Lameness published an editorial asking for a cease fire, a chance to regroup the educational effort to properly educate the horse world on what the four-point trim was all about. Farrier and author Doug Butler, PhD, called for a return to sensible shoeing. But the momentum was underway.
Farriers are not in business to be put out of business; many ceased the radical aspects of four-point trimming when they saw the blood. Hundreds flocked to seminars given by Ovnicek. Articles appeared in horse magazines, explaining the four-point trim, but always giving the now much-maligned wild horse as a model. Farriers who went to the seminars were surprised at the new view they had of the foot. One Texas farrier commented, "I attended Gene's seminar as a total disbeliever and left there with answers to questions I've had about shoeing and its impact on the hoof. It was a paradigm shift for me. I couldn't go back to shoeing the conventional way and, after a year of doing it and learning it, I am eternally grateful that I have this knowledge."
Most traditional farriers continued to dismiss anything that discussed wild horses, but at the same time, a remarkable change began to appear in general horseshoeing. More rolled-toes, rockered toes, and set-back shoes were seen coming out of stalls. Four-point advocates figured out that they had to repunch the nailholes in machine-made shoes to the outside so that the nails wouldn't penetrate the sole. "I've helped more horses in the past two years than in all my fifteen (previous years of shoeing) combined," a Nevada farrier wrote.
When asked for a comment on the four-point, or natural trimming procedure, American Farrier's Association president Lim Couch of Tennessee responded, "We do not advocate any particular method of shoeing or trimming. We advocate using a trained, competent, AFA-certified farrier."
At the 1997 Bluegrass Laminitis Symposium, Redden tempered his presentations with instructions on how to build a sole under a horse, and how to prepare a foot for a four-point trim. Meanwhile, Ovnicek was renaming his work "natural" rather than "wild horse" or "four-point" trimming. His treatment for laminitis included the use of an impression material on the sole which, over time, seemed to help the sole develop thickness, expand the heels, and develop the frog. Was this uniform pressure on the sole simulating the support of soft dirt or grass on an unshod foot?
At the same time, Ovnicek introduced the "natural balance shoe," designed to help farriers place the shoe correctly on the bottom of the foot to ease breakover. This wide-webbed, rolled-toe shoe looks foreign to most horse owners, but farriers find them easy to use and to shape to the horse's foot.
Enter a key player, Robert Bowker, DVM, professor of anatomy at Michigan State University's College of Veterinary Medicine. Bowker had spoken on anatomy of the nervous system in the foot at the 1996 Bluegrass Laminitis Symposium, and he was fascinated by the idea that wild horses' feet might somehow be different from their domestic relatives. Joining forces with Ovnicek and Colorado veterinarian Barbara Page, he enthusiastically went to work on a preliminary study, dissecting and evaluating the feet of six wild horses.
Bowker's research was presented in March 1997 at the annual meeting of the Association for Equine Sports Medicine in San Antonio, Texas. "At the start of this project, I expected the feet to be the same," Bowker said as an introduction, "but the differences are not subtle. Some wild horses' feet look like a ruminant's foot; some look like domestic horses. We assume that the differences must be related to environment."
Bowker's thoughtful presentation raised many questions for future study: Are wild horses a separate species because of this anatomical difference? Or does the hoof wall structure change due to environment? Is this a case of external stimuli vs. genetics?
The wild horses in Bowker's preliminary study, for the most part, bore their weight on their soles and frogs, which were enormous compared to the frogs in domestic horses. Wild horses living in soft ground conditions tended to develop an almost spike-like hook in their heels. All the wild horses had very thick dorsal (toe) hoof walls, but unlike in the domestic horse, P3 (coffin bone) does not have a parallel relationship to the dorsal hoof wall.
By contrast, the domestic horse's dorsal hoof wall is thin amd the caudal (heel) area is less well-developed in terms of the digital cushion and the frog.
When the microscope came out and sections of the dorsal hoof wall were examined, Bowker found some interesting differences. The normal domestic horse has both primary and secondary lamella in the dorsal hoof wall. Some of the wild horse feet showed a lack of secondary lamella; this correlated to the hoof walls that were non-weightbearing, meaning that the sole and frog bore the horse's weight instead of the wall.
Wild horses which bore their weight on the hoof wall, as domestic horses normally do, had a full complement of secondary and primary lamella.
In addition, the lamella of the wild horses were completely uniform in length, while the lamella of the domestic horses varied around the circumference of the hoof wall, with the lamella at the toe measuring two times the length of lamella at the heel.
Bowker ended his lecture with the question: If they don't walk on the hoof wall, do the secondary lamella atrophy or were they not there to begin with?
At the same AESM conference, Texas A&M researcher David Hood summarized hoof balance in a concise lecture. He covered the pros and cons of traditional "symmetrical" and "dynamic" schools of balance, but for tht first time included "natural" balance as a separate and equal theory. Hood, lead researcher at A&M's Hoof Project, stated that too much focus had been placed on "four points" of weightbearing, and that they bear the horse's weight only when standing on hard surfaces; and that four-point trimming is inconsistent with shoes and tools currently available to farriers.
The farriers were right; wild horses and domestic horses are not the same. The feet of wild horses have been able to adapt to their environment, while the feet of domestic horses seem to consistently fail at adapting and instead collapse, crack, flare, and bruise.
"We've bred the feet right off these horses," has been the moan of many horsemen in recent years. They might be right. But with an enthusiastic legion of researchers on the job to look at the domestic horse's cousins in the wild, we might one day find a genetic, mechanical, chemical, or nutritional solution for the thin-walled, thin-soled, low-heeled horses so common in our horse world.
About the Author
Fran Jurga is the publisher of Hoofcare & Lameness, The Journal of Equine Foot Science, based in Gloucester, Mass., and Hoofcare Online, an electronic newsletter accessible at www.hoofcare.com. Her work also includes promoting lameness-related research and information for practical use by farriers, veterinarians, and horse owners. Jurga authored Understanding The Equine Foot, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.
POLL: Rehabbing the Injured Horse