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Friday, July 29, 2011

Research: Clayton and Bowker's “Effects of Barefoot Trimming on Hoof Morphology” Focuses on Incremental Heel Recovery

"Lights, cameras, heel angles..." Dr. Hilary Clayton uses the most advanced data collection and analysis systems in the world to track how horses move, grow, stand or even sway. Her electronics matched with Dr Robert Bowker's anatomy studies have placed Michigan State University at the epicenter of global hoof research. Since both Clayton and Bowker espouse the advantages of barefoot hoofcare, it's natural that a study with both names as authors would be published. (McPhail Center photo)
Hilary Clayton, BVMS, PhD, MRCVS has an office in the airy, bright new Mary Anne McPhail Equine Performance Center, a state-of-the art equine sports and lameness facility at the Michigan State University College of Veterinary Medicine. It’s chock full of video equipment, sensors, high-tech saddles that need to be tested or patented, sensors, force plates, remote controls and did I mentioin sensors? There’s a feeling that if something is going to affect a change in the future for horses, its route passes through this building. You also have to wonder what the electric bill is. Everything plugs in and has a stand-by red light glowing in the dark. The sensors are always ready.

Across the parking lot looms the main vet college building and large animal hospital. You go inside and enter a labyrinth of corridors. You descend stairs. Pipes rattle. You walk down more hallways. Turn some corners. And at some point, you stumble into a place that is the antithesis of Dr Clayton’s futuristic electronic world.

You’re facing a mountain of coffin bones. Over here are some old farrier books, and through the microscope, you think you see what the classic professor Robert Bowker PhD DVM wants you to see, that a coffin bone can and does have evidence of osteoporosis.

In this lab, things pile up. They get dusty. The information is layered like the strata of a carefully dug herb garden. Deep historical reference compost and intellectual top soil combine here to make ideas grow. Theories and what-ifs sprout like weeds after a summer shower.

On weekends, Dr. Clayton's interest in dressage makes her showing schedule a living laboratory: she competes her horses unshod. Until last year, her veteran horse MSU MAGIC J competed at the grand prix level. Up-and-coming MSU FANFARE, shown here, currently leads the US Dressage Federation standings in dressage freestyle at second level. Both horses were bred by the university and selected by Dr Clayton for their movement characteristics, not their conformation. She looked for horses with good movement, instead of horses that looked like they could move.

Hilary Clayton calibrates a set of sequential video cameras and hits the “on” switch. Robert Bowker digs a little deeper, reaching for a certain specimen he knows is under the pile. He turns an idea around and realizes he forgot to stop for lunch. And that was hours ago.

Both these laboratories and both these professors study the horse’s the same university. Both are at the top of the game, and in spite of their proximity, they couldn’t be approaching the hoof from more different perspectives.

And what are the odds that if two professors at the same university were studying the same structure, they’d share a common point of view? Or that they could possibly collaborate on a research project?

College professors are often, by nature, protective of their turf. Someone else on the same campus studying the same thing should be a threat. But Clayton and Bowker have managed to put their well-stocked heads together on research for several years.

This week the latest product of their thinking-alike-but-acting-differently collaboration is a paper on how hoof morphology is influenced by a specific method of barefoot trimming. The paper was published in the Australian Veterinary Journal.

For anyone not familiar with the term, morphology is the study of shape, form and structure in nature. We use the word “morph” colloquially as a verb. When you “morph” into something else, you are changing shape or form.

Foot diagram for trimming protocol. The paper does not contain the word "breakover".

Make no mistake: this paper is not going to tell you how to rehab a horse's hoof. It is, however, going to give more credence to the idea that a specific method of barefoot trimming can successfully achieve a precise goal. Because it did, in the hands of Clayton, Bowker et al.

To be clear, Dr. Clayton is listed as the lead author, with Bowker's name fourth. His inclusion in the study is evident in the discussion section, where information on sensory nerves in the foot is shared. His inclusion also means the study is destined for wide readership among his many followers.

The paper begins with an important sentence that bears repeating. Memorize it: "There is little scientific data describing the effects of any type of barefoot trim, particularly in horses that participate in regular exercise in a riding arena, or how such trimming may affect the overall conformation and health of the foot for an extended period of time."

The problem: horses with mildly underrun heels. The goal: palmar/plantar migration of the heel area of the hoof, increase in heel angle and support length, and an increase in solar angle of the coffin bone. The hypothesis: it's possible.

Michigan State University's McPhail Center is where horses, data and electronics come together.
And not only is it possible, it's possible to do it with a rasp, not a wedge pad or a horseshoe. It's possible to do it so that the inside structures are not disturbed by cranking the hoof capsule into alignment in one shoeing, running the risk of creating separations and flares and adding strain to repositioned ligaments and tendons.

The research project achieved its goals, but it is important to note that this was achieved not by removing shoes, but by applying a specific trimming technique and repeating it, over and over and over.

In the end, the heel angle increased an average of almost nine degrees. The difference between toe and heel angle decreased from 13.8 to 7.2 degrees during the one-year maintenance period.

There are some key elements to this study that must be understood: The horses lived in a pasture, not in stalls. They received regular daily exercise (one to three hours) under saddle on a sand arena in a riding program five days a week. The horses were all Arabians of similar height and weight and age (average 13.6 years).

The horses in the study were barefoot before the research began, so they did not have to go through a transition-to-barefoot period. They were trimmed by one farrier (Cappi Roghan, who deserves some credit) throughout the study; he understood his assignment and acquiesced to stick to the program.

In the end, this study is not a victory for barefoot over shoes. This is a victory for showing that trimming alone can achieve a morphological change.

It just takes a lot of time, that's all.

The timeline of the study would not be considered a victory. It took four months of conscientious trimming to reshape the horses’ hooves, and then 12 additional months for the hoof to grow and stabilize in order to complete the study and prove the trim's effect. The authors felt that 16 months was required, based on the premise that a horse’s hoof grows an average of one centimeter per month, so that each horse, by the end of the study, would have had ample time to grow a completely new hoof.

The interesting aspects of the study are the way that the hoof morphology changed in one aspect then changed back. For instance, the area of the frog initially increased, then decreased.

The authors suggest that the horses’ feet at the beginning of the study illustrated the characteristics of wild horses living on soft sandy substrate, as documented by Brian Hampson PhD at the University of Queensland in his recently completed doctoral thesis, The Effects of Environment on the Feral Horse Foot.

The increase in toe angle during the initial transition period was an average of 2.7 degrees. Because this change was gradual, the authors commented that the trimming technique allowed the foot’s internal structures to gradually adapt, without any pathological consequences such as wall flares.

It should also be noted that the authors concurred that the goals of the trimming—palmar/plantar migration of the heels, increases in heel angle and support length, and increased solar angulation of the coffin bone -- are potentially beneficial to the health of the foot.

The key sentence to this study is found near the end of the paper: “Current knowledge of hoof structure and dynamics is incomplete and these ideas, while speculative, may provide a stimulus for further research.”

Note: The study was supported by the Bernice Barbour Foundation and the American Quarter Horse Association. The research team consisted of, in addition to Drs Clayton and Bowker, veterinary student Sarah Gray and MacPhail Center lab manager LeeAnn Kaiser.

Clayton, H., Gray, S., Kaiser, L. and Bowker, R. (2011), Effects of barefoot trimming on hoof morphology. Australian Veterinary Journal, 89: 305–311. doi: 10.1111/j.1751-0813.2011.00806.x

Dr. Clayton on biomechanics of footing for dressage horses, part 1

Dr. Clayton on biomechanics of footing for dressage horses, part 2

To understand the full spectrum of hoof science, it is necessary to consider that it is much more than anatomy and physiology. The hoof is in motion, and how it moves affects its shape, its health and the relative condition of its components. Biomechanics means much more than trying to judge if a horse is landing heel-first or not.

You may need to adjust the volume on your computer. Watch as Dr. Clayton describes the mechanics of how the hoof of a dressage horse interacts with the arena footing. Filmed at the 2007 Adequan/ USDF Annual Convention in Orlando, Florida, this video is available on DVD with several other lectures on hoofcare and lameness from the USDF web site.

The abstract for this article is available online: The Australian Veterinary Journal: Effects of barefoot trimming on hoof morphology. You can also purchase a download of the complete article.

Click on ad image for details; image from Dr. Bowker's research at Michigan State U.

 © Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site,, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to  
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Heidi Meyer said...

Awesome and needed discussion! If more people (farriers, vets, trainers, owners) understood how the hoof actually works....they would understand why shoes cause problems and how poor footing affects performance/health of their athletes.
Kudos to Dr. Clayton and Dr. Bowker for their dedication.

cheryl said...

Thanks for the great article Fran.

My horse was in the earlier phase of this barefoot trim study when they were calling it the physiological trim about 5 years ago. Back then we had a group of differeent breed, age, history, relatively sound, of various uses, privately owned horses we owners would each trailer in to be trimmed, X rayed, marked up and trotted over Dr. Clayton's force plate to gather the data. Being scientists I can see where they moved on to use a more controlled group of horses.

You may also be interested in Dr. Debra Taylor's study at Auburn University using basically the same trim but more or less unloading the hoof wall to rehab foundered horses. They're using a unique way to diagram the radiographs to chart progress.

Jon said...

Thanks for an informative article. Do you have any examples of Grand Prix Showjumping Horses barefoot?

I'm talking sustainability at the top level over a long period?

Fran Jurga said...

Hi Jon, sorry but I don't know of any grand prix show jumpers that compete without shoes. That doesn't mean there aren't any. There was a show hunter in Calfiornia who did very well last year; Erin Gilmore wrote an article about it in The Chronicle of the Horse, but I'm not aware of any of the grand prix horses competing without shoes. If you hear of any, let me know.

Fran Jurga said...

Jon, I should add that there is a gallery of barefoot performance horses on the anhcp Facebook page. It shows several jumpers but no details on what level, whether AO, GP, or breed shows. Still pretty impressive! The Zephyr horse (show hunter) from California that I mentioned is shown.