Owl Canyon Hoof Care and Rehabilitation

Blaine St. Peter Ft. Collins, Colorado             970-420-5496 

  

A very good article by my great friend Rachel Chao, MS


Why I don’t shoe my horses.

By Rachel E. Chao MS

Ó 2007 Natural Hoofworks, LLC. 

If you ask 3 different horse owners their opinions on any different subject, you’re likely to get 5 different answers.  It can be confusing and terrifying when the advice you receive is contradictory, and everyone giving the advice claims that if things are not done precisely their way your horse will inevitably colic/founder/smell bad/ lose a limb/grow a fungus/become a social pariah/etc. 

I believe that most people shoe their horses because they believe it is in the horse’s best interest.  I know that is why I used to keep my horses shod.  I trusted the advice I got from more experienced horse people and professionals.  It never occurred to me to question the use of horse shoes, because literally all the horses I ever came into contact with were shod.  My horses needed shoes to protect their feet from rocks and gravel and pavement, just like I needed my boots to protect my feet.  It would have been cruel to do the kind of hard, fast mountain riding I liked to do without giving my horses the benefit of shoes.  Not only that, my horses did not have the best feet to begin with.  Their angles always looked too low to me, I could never get them to grow enough heel to “stand them back up”.  Without the shoes to keep them from wearing away the heel, how could I ever get the angles better?  Also, when I did pull their shoes for a few weeks a year, the feet immediately started to crack and chip and lose chunks.  It appeared that the only thing holding my horse’s feet together was the shoe itself. 

Since those days I have learned a lot about the relationship between the feet and the overall biomechanical function of the animal.  The constant in this learning process has been that the more I know, the more I learn I don’t know.  I have however, since beginning serious study of the horse’s foot, learned certain facts that have led me to make the decision to no longer use affixed shoes for my horses.  I would like to share my reasoning with you, but before I do I think it’s important to make three points:  

  1. There is no shortage of misinformation about the hoof in circulation. In order to make educated choices, it is important to learn all you can, and question everything in order to protect yourself against wrong and potentially dangerous information.  Whenever possible depend on information that has actual verifiable, reproducible data behind it.  People may be passionate about their theories and opinions, but that doesn’t make them reliable. 
  2. Not all methods of hoofcare (barefoot or shod) are equal.  Just because a method is labeled ‘natural’, does not necessarily mean it is.  I would discourage the use of any method that does not leave your horse as comfortable and usable right after the trim as before.  The same goes for any method that is trying to trim for a certain ‘look’ or geometric proportions instead of correct movement.  Finding competent hoof care is a buyer beware process.  The best gift you can give your horse is to educate yourself!
  3. No one has all the answers and I do not intend for this article to give them all.  A man I met on the trail told me the story of his introduction to natural hoof care.  A friend introduced him to a ‘natural hoof guru’, who proceeded to read him the laundry list of things he saw wrong with his horse’s shod feet.  The conclusion the guru came to was that this man’s horse was in such bad shape that he would not be rideable without a long rehabilitation process, and even then the horse’s prognosis was iffy.  After this examination the man revealed to the guru that he had just finished 250 competitive endurance miles in the past several months, including the 100 mile Tevis cup with excellent vet scores.  Understandably, this experience made him very unmotivated to learn about natural hoof care.  It is not my intention that this information be used to bully anyone into my way of thinking, just to share the train of thought that led me to my conclusions about hoof care.

 

That said, the biggest areas of misconception that keep people in horse shoes are: 1). What the hoof’s capabilities are,  2). What the shoe protects, and 3). The physiological differences between a shod and unshod hoof.

Capability of hoof

 

Modern horse evolved about 3 million years ago, but has only been domesticated for the last 5000 years. Historically, horses were not shod until their natural lifestyle was compromised by a drastic change of environment as they were brought north into Europe.  The lack of movement (many were kept in tie stalls standing in their own waste) combined with the new unnatural diet (rich green cool weather grasses and cereals) rendered many horses unsound for use, so a “metal hoof wall” was invented to hold the hoof together and protect it against harsh terrain during warfare and draught work.  But what about the first 4000 years of domestication, before the advent of the horse shoe? 

Before the advent of the horse shoe Egyptians, Persians, Greeks, Macedonians, Romans, Mongolians and others all successfully used horses in terrain as harsh and varied as the lands they conquered.  The barefoot horse carried generals and armies across the expanse of the known world for thousands of years.  Bucephalus did not need an iron shoe to take Alexander the Great over hundreds of miles of treacherous mountain and desert and jungle. The horses that performed these feats are anatomically and physiologically the same animals today that they were several thousand years ago.   

Although the tradition of riding truly high performance barefooted horses was lost for a few hundred years (a short span of time in the history of the horse’s domestication), we are once again beginning to see equine athletes performing successfully in a variety of disciplines without shoes.  From endurance riding to dressage to reining, when living conditions, diet, and hoof care are reasonably natural, these horses are able to meet and exceed expectations of athleticism and longevity.  There is nothing a horse can do shod that he cannot do barefoot or booted (the horse shoe of the future!). 
 

What the shoe protects

 

Although for 80% of the horse’s domestication he performed for us unshod, is there any benefit in nailing a shoe on his foot? Is it possible to improve on nature? 

To answer that question, we have to look at what the shoe is actually designed to do.  As mentioned before, it was made as a sort of ‘metal hoof wall’.    In the natural healthy hoof, the horse’s weight is designed to be distributed across the hoof wall and the sole (Simons-Lancaster, 2004).  To prevent the hoof wall from overgrowing the sole and unbalancing the weight distribution of the horse, the hoof wall is designed constantly wear down a little with every step to maintain a balance with the rate of growth.  When we nail a shoe on, two things immediately happen: 1. The sole and frog are both raised off of the ground and taken out of function, but left exposed and unprotected (in standard keg shoes—in some shoeing set ups this is not the case). 2. The hoof wall no longer wears away at the rate it is meant to, and indeed does not wear away at all until the next time the shoe is pulled and the hoof is trimmed.  Therefore the shoe ‘succeeds in protecting’ the one part that is supposed to wear constantly.

 

The difference between shod and bare

Although it appears now that the shoe does not actually protect what we thought it did, and may not be necessary, is there any harm in it? 

Here are some of the effects of shoes that have been discovered so far: 

Decreased shock absorption. Studies which have measured the impact vibrations on the inside of the hooves of shod and unshod horses have found significantly less ability to dampen vibrations in the shod foot.  This is thought to be due to the more limited motion of internal and external structures of the foot while shod (Dyhre-Poulsen, Smedegaard, Roed, and Korsgaard, 1994).  Although the heels still do expand in the shod hoof on impact as much as in the unshod hoof, it appears that the rest of the hoof capsule is not as capable of natural flexion (Colles, 1989).  This is especially pertinent to horses working on hard terrain (Simons-Lancaster, 2004).  There are also anatomical differences in the structures in the rear of the foot responsible for shock absorption (see below). 

Faster breakover (less flexing of foot).

The shod hoof breaks over faster than the unshod hoof.  This means the foot has a “snapping” lever action as it leaves the ground, instead of having the flexibility to leave the ground in gradual stages (somewhat like the human foot rolls off the ground from the heel to the ball to the toe).  This is a drastically different movement pattern than the horse is designed to exhibit.  The result is that the foot has less time before it leaves the ground to dissipate energy, and may result in ossification of the lateral cartilages (Simons-Lancaster, 2004). 

Decreased circulation.

Whenever the hoof is peripherally loaded (i.e. the weight bearing is only around the outer rim) doppler radar studies have shown that the perfusion of blood in the hoof is only between 50 and 65 %.  This is in comparison to a horse with even loading over the sole (such as  barefoot standing on pea gravel), that has approximately 90% perfusion.  Even glue on or rubber shoes by their very design peripherally load the foot, thereby reducing the perfusion of the tissues while the horse is at rest (Bowker, 2007c).

The differences in circulation during movement are difficult to study for obvious reasons.  However, it has been shown that the negative pressure phase as the hoof becomes weight bearing (responsible for creating the vacuum to draw blood into the hoof) is shorter in shod horses than barefoot (Simons-Lancaster, 2004). 

Mechanical damage to hoofwall.

This has not been studied, but can be observed whenever a shoe is pulled.  Nail holes (opening tissue to fungal infection), chunks of hoof wall torn away, and in bad cases nails going through sensitive internal structures (quicking) are all examples of this. 

Thinning of sole (lowered P3 position). 

This is best observed in radiographic studies, although there are less precise ways to gauge sole thickness without these measures.  In order for a shoe to be nailed onto the hoof, the hoof must be flattened to make an adequate interface.  Rasping the foot flat necessitates the thinning of the sole.  The more the sole is thinned the less a healthy sole callous can develop. Less material is under the coffin bone to support, and  it can begin to sink in the hoof capsule.  This repositioning of the coffin bone is what makes it so dangerous to try and overly shorten a long hoof capsule in one session, when signs show the sole is thin.  The solution for this problem is to leave the sole alone to callous, regain concavity, and gradually reposition the coffin bone higher in the hoof capsule (Ramey, 2002). 

Unnatural distribution of weight (peripheral loading). 

In the discussion of what the shoe actually protects, we discovered that the weight bearing responsibility is shared by the hoof wall and sole.  When a shoe is nailed on, the effect is to ‘hang’ the weight of the horse from the hoof wall, placing undue stress on the wall and the lamina.  As the wall grows longer and is unable to wear away, this unbalance becomes worse (Simons-Lancaster, 2004; Ramey, 2002). 

When peripheral loading occurs, it can actually change the anatomy of the foot.  In areas of increased stress the lamina begin to bifurcate (divide into multiple, thinner weaker lamina).  Horses who are shod tend to have a greater amount of lamina, which are thinner than barefoot horses.  When the load is borne on the periphery of the foot, changes can also happen to the coffin bone.  Similar to osteoporosis in humans the bottom of the coffin bone does not receive enough load, and begins to demineralize.  The load from the shoe is reflected up the hoof wall and places unnatural pressure against the higher portions of the coffin bone and lateral cartilages and can cause bone to be laid down where it should not be (Bowker, 2007a, Bowker, 2007b).  

IMPAIRED DEVELOPMENT OF Digital Cushion and Lateral Cartilages!!!

This fact is perhaps the most damning against the use of shoes, especially on young horses.  The digital cushions (DC) and Lateral cartilages (LC) are soft tissue structures in the back of the foot which are responsible for cushioning the landing of the horse and allowing the back of the hoof capsule to flex for shock absorption and circulation (the front of the capsule is held rigid by the coffin bone).  The DC when it fully develops is a tough fibrocartilagenous mass, and the LC  is an inch thick highly vascularized  tissue.  When a shoe is placed on a horse, the development of these structures stops.  The DC remains a jello-like fat deposit, only capable of supporting a foal’s weight, and the LC remains thin and nearly devoid of blood vessels, impairing the hydraulic shock absorption system of the foot. The underdevelopment of these structures changes movement patterns, subjecting the horse to massive tendon and ligament damage, and greatly increasing the risk of disorders such as navicular syndrome and contracted hooves. (Bowker, Atkinson, Atkinson, and Haut, 2001; Bowker, Van Wulfen, Springer, and Linder, 1998; Bowker, 2007).    This is, in my opinion, one of the most important considerations in not shoeing horses, especially young ones.

Even if, in your heart of hearts, you do not believe that horses are capable of carrying a human barefooted, technology now exists (i.e. hoof boots) that protects the horse’s foot without the negative side effects of shoes.  This technology grows better every year. 

In conclusion, the choice to go barefoot was easy for me to make, when I was presented with the best current knowledge.  In the years I have tried it, I have not been disappointed, and I have learned to overcome the obstacles that kept me shoeing my horses before.  I hope that the information that helped me to come to my decision, helps you in some way to think about the decision you have to make about the care of your horse’s feet.  In the end, we are all responsible for doing our own research about what is the healthiest for our own animals.  I wish you the best of luck in this endeavor. 

Works Cited

 

Bowker, R.M.,  Atkinson,P.J., Atkinson, T.S., and Haut, R.C. 2001.  Effect of contact stress in bones of distal interphalangeal joint on microscopic changes in articular cartilages and ligaments.  American Journal of Veterinary Research 62, no.3: 414-424. 

Bowker, R.M., Van Wulfen, K.K., Springer, S.E., and Linder, K.E. 1998. Functional anatomy of the cartilage of distal phalanx and digital cushion in the equine foot and a hemodynamic flow hypothesis of energy dissipation. American Journal of Veterinary Research 59, no.8: 961-968. 
 

Bowker, R.M.  “Contrasting structures of good and bad feet.”  University of Colorado, hoof care seminar. Ft. Collins, CO. 5 August, 2007a. 

Bowker, R.M.  “Growth and Adaptive Capabilities of Hoof Wall and Sole: Functional Changes in Response to Stress.”  University of Colorado, hoof care seminar. Ft. Collins, CO. 5 August, 2007b. 

Bowker, R.M.  “Doppler Ultrasound on the Equine Foot and determining the normal physiological functioning of vascular flow during health and disease.”  University of Colorado, hoof care seminar. Ft. Collins, CO. 5 August, 2007c. 

Colles, CM. 1989. The relationship of frog pressure to heel expansion.  Equine Veterinary Journal 21, no.1:13-16. 

Dhyre-Poulsen, P.,  Smedegaard, H.H., Roed, J., and Korsgaard, E. 1994. Equine hoof function investigated by pressure transducers inside the hoof and accelerometers on the first phalanx.  Equine Veterinary Journal 26, no. 5:362-366. 

Ramey, P. 2002.  Making Natural Hoofcare Work for You. Star Ridge Publishing; Harrison. 

Simons-Lancaster, L. 2004. The Sound Hoof: Horse Health from the Ground Up. Tallgrass Publishers, LLC; Larkspur.