Sheared Heels: Nature or Nurture?

Have you ever paid attention to the way people walk? Some are pigeon-toed, others are "duck-footed." Some wear the insides of their shoe heels; others do just the opposite. Yet, most are perfectly "sound" and healthy.

The same principle is true for most horses, asserts farrier Rob Sigafoos of the University of Pennsylvania’s New Bolton Center in Kennett Square, where he specializes in corrective and therapeutic shoeing and hoof care. Of course, horses don’t have the range of motion in their hooves that we do in our feet, so their hooves’ flight and landing patterns are less diverse than ours. Instead, the hooves themselves reshape and conform to the inevitable departures from the textbook descriptions of perfect conformation and movement--a testament to their remarkable ability to adapt, Sigafoos says.

Many hoof problems actually are "man-made," says Sigafoos. They are the result of someone’s attempt to make hooves look textbook-perfect, not realizing that certain hoof shapes or structural characteristics might, in fact, be necessary adaptive changes. These man-made problems can include such diverse conditions as underrun or contracted heels, navicular syndrome, and hoof cracks. Also symptomatic of "cosmetic shoeing" and trimming, he says, can be the condition known as sheared heels. It might not be a singular cause of lameness by itself, but it is a reason to have the horse examined to determine its possible source. It can cause problems which, at times, are not always easy to repair.

So far, sheared heels sounds pretty minor on the hoof-health scale. But in truth, it’s not that simple. Although many experts agree that improper trimming can lead to sheared heels, they hold differing views on other contributory factors and advocate different approaches to treatment. In this article, we’ll outline the theories of the causes of sheared heels, we’ll tell you which horses appear most susceptible to the condition, and we’ll explain the various therapeutic options. Most important, we’ll give you tips on how to prevent your horse from developing sheared heels in the first place.

Sheared Heels Defined

Sigafoos agrees with the definition of sheared heels as presented by Bill Moyer, DVM, and farrier Jack P. Anderson ("Sheared Heels: Diagnosis and Treatment," Journal of the American Veterinary Medical Association, Vol. 166, 1975): a displacement of the coronary band of the hoof, causing the corresponding heel to be pushed up and out. If you look at an affected horse’s hoof from the rear, you’ll see that the coronary band isn’t level as it follows the curvature of the heel; the line over the "sheared" heel is higher than that over the normal heel. Sheared heels can occur in hind feet as well as in forefeet.

In a bona fide case of sheared heels, the affected heel is at least 0.5 centimeters higher than its mate, writes Stephen O’Grady, DVM, MRCVS, of Northern Virginia Equine, The Plains, Va., in "Sheared Heels" on the web site. The University of Minnesota’s Tracy Turner, DVM, DACVS, also refers to the half-centimeter definition in his article "Objective Assessment of Hoof Balance," also published on The hoof wall on the affected side is straighter and the opposite hoof wall is more flared, O’Grady adds.

This condition shouldn’t be confused with another hoof problem that’s sometimes erroneously referred to as sheared heels, says Sigafoos--the formation of a deep cavity in the central sulcus (the cleft between the heels), which can lead to a serious case of thrush (a malodorous fungal infection) and can cause lameness.

In Sigafoos’ experience, sheared heels often occur in conjunction with other hoof conditions, such as heel and quarter cracks and contracted heels. (Which causes which? It’s a "chicken-or-the-egg question.")

What Causes Sheared Heels?

O’Grady, Turner, and Sigafoos agree that improper hoof balance can predispose a horse to developing sheared heels, but there appears to be some disagreement as to the origins of the imbalance. O’Grady begins by presenting the conventional wisdom, then disproving it. Previously thought to cause sheared heels was the following: "Improper trimming and shoeing have been blamed as the most common cause of sheared heels. Excess hoof wall is removed from one heel, creating an imbalance. Because the heels are a different length and height, a disproportionate force is placed on the longer heel during weight-bearing. This causes an abnormal shearing force between the heels, structural breakdown occurs, and the affected heel is driven upward." He successfully disproved this theory, he continues, by intentionally lowering one side of horses’ feet in an experiment; no horse developed sheared heels as a result of the deliberately uneven trimming.

Instead, he writes, conformation might be to blame--in particular, a base-narrow, toed-out conformation which causes the hoof to land first on the lateral side (the outside of the wall) rather than flat. The lateral heel suffers greater-than-normal pounding and can become bruised, while the "secondary impact" on the medial (inside) heel can cause the medial heel to shear, he asserts.

Although he agrees that conformation is the most likely culprit in a case of sheared heels, Sigafoos disagrees with O’Grady’s pinpointing certain conformational characteristics as predisposing a horse to developing the condition. Sigafoos says a sheared heel "doesn’t necessarily relate to the side of the hoof wall the horse lands on." Furthermore, he says, he believes the condition has less to do with a horse’s basic limb stance than with the relationship of the coffin bone to the long and short pastern bones. He says he’s observed "a correlation between an offset coffin bone and sheared heels. Most commonly, the coffin bone is offset laterally (positioned slightly to the outside, rather than directly underneath), and the resulting concussive forces cause the medial (inside) heel to shear."

Sigafoos cites a second possible cause of sheared heels that the other experts don’t mention--environment. "In my experience, moisture plays a role" in the initial appearance of the condition, he says. Sigafoos believes that if a horse lives or works in a very dry environment, especially if his hooves tend to be dry to begin with, he’s more likely to develop sheared heels, contracted heels, or both. This perhaps is because the dryness causes the heels to lose their fleshy, spongy properties and the resulting concussion exacerbates any existing, minor hoof imbalances. As evidence, he says he most often sees sheared heels in harness-racing Standardbreds. "They race on stone-dust tracks--very dry footing--and the friction between their hooves and the track surface produces so much heat that their hooves and shoes are actually hot to the touch when they’re done training or racing. To try to counteract the heat and the dryness, most harness track grooms apply heavy poultices to their horse’s feet after it works or races, often bandaging the entire foot in an attempt to rehydrate it. Hooves don’t absorb much moisture from the environment--most of it’s supplied internally, via the circulation--so you have to take a really aggressive approach to do any good."

Sigafoos says he also sees the condition in a number of Quarter Horses, perhaps due to their "upright feet and tendency toward contracted heels. It is not unusual to see this condition in sport horses (hunters, jumpers, event or dressage horses), it is just far more common in Standardbreds and Quarter Horses."

Treating Sheared Heels

The conventional treatment for sheared heels, says Sigafoos, is to trim the hoof to leave a small gap (the thickness of the width of a couple of pennies) between the sheared side and the shoe, and to apply an egg-bar shoe to encourage the hoof to land levelly. In theory, the higher heel will be able to drop back down into place, aided perhaps by warm-water soaks or poultices to help the hoof structures become moist and pliable. Unfortunately, he says, this approach "doesn’t work well."

To help correct extreme cases of sheared heels, he’s fashioned special horseshoes out of leaf spring (a spring made from banded, curved metal strips) to allow "give" over the sheared heel. After the hoof has assumed a more normal shape, he says, use of a bar shoe and frequent trimmings (as often as three to four weeks for horses with chronic hoof problems) can help prevent the problem from recurring.

Other treatment approaches include the removal of the shoe and an intensive period of soaking to encourage the hoof to assume a more normal shape, accompanied by the administration of "bute" to discourage inflammation and laminitis-like symptoms, according to O’Grady. Some specially designed rim pads, such as the Luwex pad, are marketed as a treatment for sheared heels because of the pads’ shock-absorbing qualities, according to EQ Inc., the pads’ manufacturer. (When Sigafoos was asked about the usefulness of such pads, he said he hadn’t had experience with such products.)

As with many other health problems, prevention appears to be more effective than treatment. "Keep your horse’s feet short, and don’t let his toes or heels get long," Sigafoos advises. "The common shoeing cycle, in which the foot is allowed to get long and to change shape before it’s trimmed back into balance, is very hard on your horse’s leg and hoof structures. It’s much better to maintain that balance with more-frequent trimmings."

Could this be just a way to pad farriers’ pockets? Sigafoos says no. "Most good farriers have far more work than they can handle, especially in the warm-weather months."

Another preventive measure that might be beneficial, Sigafoos adds, is to adopt the harness-track practice of regular poulticing if your horse’s feet are very dry. If you’re not sure whether his feet are dry enough to warrant poulticing, check with your veterinarian.

The Good News About Sheared Heels

"I may get in trouble for saying this," says Sigafoos, "but I don't consider sheared heels to be that big of a problem." He considers navicular syndrome, laminitis, hoof cracks and the like to be far more severe, and adds that sheared heels alone rarely cause lameness. With the implementation of a trimming and shoeing strategy that allows the horse to move and land in balance with his own unique conformation, he says, most cases of sheared heels clear up on their own.

About the Author

Jennifer O. Bryant

Jennifer O. Bryant is editor-at-large of the U.S. Dressage Federation's magazine, USDF Connection. An independent writer and editor, Bryant contributes to many equestrian publications, has edited numerous books, and authored Olympic Equestrian. More information about Jennifer can be found on her site,

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