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Volume VIII: Shoeing Essentials

Volume VIII
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Shoeing Essentials
How will you know if your horse’s shoes fit? A top farrier explains what to look for to be sure.

By Rodney King, CJF, AWCF, with Elaine Pascoe

Your farrier has come and gone, leaving your horse with a new set of shoes. His feet look great, but you can’t help wondering: Was the job done right?

That’s an important question, because good shoeing is essential for every horse.  Whether yours is an Advanced eventer, a Grand Prix dressage star or an occasional trail mount, he needs to be sound to do his job. The basics of trimming and shoeing are the same regardless of how your horse is used, and if they’re not done right he’ll break down sooner or later. That’s why a good farrier is as invaluable for a backyard horse as for a top competitor.

In this article I’ll tell you what to look for when your horse is trimmed and shod, and I’ll explain how some common hoof abnormalities may arise.

Because every horse is different, there is no one “right” way to shoe a horse--shoeing has to accommodate the individual horse’s conformation and use. But some basic principles apply to all, and one of the most important is balance.

A foot is balanced when it lands flat (or slightly heel first) with the lateral (outside) and medial (inside) portions of the hoof wall meeting the ground at the same time. A small degree of imbalance can be hard to detect when your horse is moving, but over time imbalance produces visible changes in the hoof. You can spot them if you stand your horse square; with his weight evenly distributed on his four legs, and look at his feet from the front, sides and back. Then pick up each foot and examine it from beneath.

Here’s what to look for:

  • Viewed from the front the coronary band ideally should be level to the ground, not rising to one side.
  • The walls should be straight, not dished or flared at the toe or on either side. The medial wall may be somewhat more vertical than the lateral wall, especially in the hind feet; but dishing and flaring suggest imbalance--the wall is pushed out unevenly at breakover (the point just before the foot leaves the ground) or on landing.
  • Growth rings--fine horizontal lines running across the hoof wall--should be evenly spaced and parallel to the coronary band. (Deeply grooved and ridged growth rings are often markers of past health problems including fevers, laminates or nutritional changes that affect hoof growth.)
  • Unevenly spaced rings suggest that weight isn’t distributed evenly on the foot-the part of the hoof that under the greatest load grows slowest. If growth rings are wider in front than on the sides, then the toe is growing faster that the heels; the heels may be under excessive stress. If the rings are wider at the heels, growth is shut down in the toe. That’s a typical pattern for a more upright club foot if the rings are wider on the medial hoof wall, the horse is putting more weight on the lateral wall.
  • Viewed from behind, the heels should be even. If one consistently takes more weight than the other, it will gradually be pushed up.
  • Viewed from below, the foot should be symmetrical, with similar amounts of hoof on each side of a plump, healthy-looking frog. A good front foot is rounded, slightly longer than wide; hind feet generally have more of an oval shape. If you draw an imaginary line across the widest part of the foot, there should be roughly as much length from the line to the point of breakover (the most forward point of ground contact) as from the line to the heels.
  • Shoe wear patterns may also show imbalance. If your horse has long toes and low heels, for example, the shoes may show wear at the heels.

When people talk about hoof angles, they usually mean the angle of the hoof wall at the front (the dorsal wall) relative to the ground. You may hear it said that front hoof angles should be 50 to 55 degrees, and hind feet a bit steeper. While that may be typical, there is no magic number. A horse’s ideal hoof angle depends on his conformation-some are steeper, some shallower and some are mismatched in front or behind-but a few principles apply.

Here’s what to look for:

  • Viewed from the side, the slope of the dorsal wall should match the slope of the pastern. This suggests that the bones in the foot align correctly with the long pastern bone. It would take an X-ray to see what’s really going on inside of course. A broken hoof-pastern angle, however suggests that the bones, tendons and ligaments aren’t positioned to disperse your horse’s weight as they should and therefore may be under stress.
  • As a rule, the hoof and pastern angle should mirror the shoulder angle, so you can use that as a guide to what’s right for your horse.
  • The heel angle should be similar to the angle of the foot wall. If it’s slightly shallower (as is often the case) that’s generally not a problem, but markedly shallower heel angles go along with long-toe, low-heel imbalance. His weight isn’t being evenly supported, and this can lead to soundness problems down the road.

At breakover, your horse’s weight has passed over the foot and the foot begins to lift. The breakover point is the last point of the hoof or shoe to come off the ground, and as a rule it’s at or near the toe. Long toes delay breakover. This doesn’t lengthen the stride, as some people believe; it does put extra stress on the deep digital flexor tendon and ligaments at the back of the foot and on the navicular bone, as the tendon and ligaments press and pull on it. A horse with a normal foot may be shod with a little rocker at the toe to facilitate breakover; for therapeutic shoeing, we may do more.

Where should your horse’s breakover point be? That can be difficult to determine by just looking at the hoof. Mechanically, it relates to the location of the bony column in the foot, which you can’t see. But if his hoof and pastern angles align and the dorsal wall is straight, not flared, then it’s probably OK. If you see that the toe is flared or that the slope of the pastern is steeper than the slope of the wall, that suggests the toe is too long.

Farriers use a number of external landmarks to judge the position of internal foot structures. One is Duckett’s dot (for Dave Duckett, a British farrier who came up with a widely used system for assessing hoof balance), and imaginary point that correlated to the point where the deep digital flexor tendon attaches to the coffin bone. On an average horse, the dot is about 3/8-inch behind the tip of the frog. The farrier can determine a good toe length by using a compass or dividers, first measuring from the dot to the medial wall and then scribing an arc on an equal radius to the toe.

Fit and Finish
Your farrier should shape the shoes to fit your horse’s feet, not shape his feet to the shoes. This can be done equally well with hot or cold-shoeing techniques. I hot shoe everything because the shoe is easier to shape when hot, and that’s just physically easier for me. Many farriers cold shoe with excellent results. It isn’t necessary to “burn” the shoe onto the foot to get proper fit- that’s accomplished by ensuring that the hoof is trimmed correctly and the shoe surface that meets it is flat.

The shoe should give support to the entire wall, toe to heels. Typically the farrier sets the shoe flush with the wall in front but extends it past the hoof wall, just enough to stand a penny on edge, from the widest point back to the heels. This allows the heels to expand under your horse’s weight. In practice, the amount of expansion room your horse needs depends on what he’s doing, his conformation/way of going and the environment.

If he’s at risk of stepping off his shoes--because he plays hard in his paddock, works on muddy or trappy ground, or performs in a discipline that calls for tight turns and speed--he may need to be shod tighter. In this case the feet will quickly overgrow the sides of the shoe, so keep him on a short shoeing schedule.

A horse with low heels or weak or unbalanced feet may benefit from more width to give his feet more support. Then, to keep the shoes on, you may need to keep him off muddy ground and ensure he doesn’t go too wild in his paddock.

Nails should be placed no farther back that the widest point of the hoof to allow the heels to expand. Fewer nail holes are better, but the shoe must stay on the foot. For a strong foot, six is average. In a nicely finished shoeing job, the nails are clinched smoothly at the wall and lined up parallel with the ground. Keep in mind that finish isn’t function, though--what matters most is how the foot is trimmed and how the shoe supports it.

Some common hoof problems stem from imbalance in the foot.

Underrun heels can develop from long-toe, low-heel imbalance. The heels gradually become lower and lower until they’re crushed forward under the foot, becoming part of the weight-bearing surface. The correction is to unload the heels by providing support (with a heart-bar shoe, for example) while moving the breakover point back with judicious trimming and shoes that ease breakover (with rocker toes, for example).

Sheared heels develop from medial-lateral imbalance. The heel on the side that meets the ground first is pushed up. Corrective shoeing and trimming to restore medial-lateral balance will help the heels to grow out evenly. (For photos of underrun heels and sheared heels, go to www.PracticalHorsemanMag.com)

Vertical Cracks can start at ground surface near the toe or at the quarters, wherever imbalance puts excessive stress on one portion of the hoof wall. Hoof condition can be a factor; weak, shelly walls are prone to cracking. Cracks can be serious if they spread up, penetrate sensitive tissue and allow infection to enter. Your farrier can take steps to keep the crack from getting worse, but to fix it you’ll need to correct the underlying imbalance and ensure that the feet are healthy. While it may be tempting to blame the farrier, often your horse’s conformation is the root of these problems. For example many horses toe in or toe out to some degree in one or both front limbs, and that contributes to medial-lateral imbalance. So does base-narrow conformation, in which the legs (viewed from in front or behind) are closer together at the ground. Horses with sloping pasterns are often prone to underrun heels. Some conformation problems can be improved when the horse is young, but once a horse is mature much less can be done. When a horse toes in or out, for example, often the leg itself is rotated or the horse has an angular deformity of the knee or fetlock. A farrier can make the horse seem to stand or move straighter, but this is more an optical illusion-the conformational problem is still there, and changing the foot to disguise it puts added stress on joints, tendons and ligaments. You can’t torque these structures too much without causing soundness problems down the road, so the best course is to balance the feet to accommodate your horse’s conformation. Stick to a regular trimming schedule because long feet will make these problems worse.

What if...
His feet don’t match.

Mismatched feet are common. Often one front foot is a bit flatter than the other or the shape of the hoof is slightly different. Your horse’s conformation is usually the reason; it can be minor, a slightly shorter tendon in one leg, for example.

A farrier can disguise the difference by filing down or building up sections of hoof, but this doesn’t work for long. I never try to match the feet. When feet and legs have different conformation, the feet need to be trimmed to accommodate their unique characteristics. If you address individual issues, correcting the balance so that each foot lands correctly, over time the feet gradually become more similar.

He loses shoes.

Shoes don’t just fall off; if your horse loses shoes there’s a reason. Replacing lost shoes is frustrating and tires your farrier, too--so talk to him and see if the two of you can come up with a solution.
Ask yourself, where did the shoe come off, and what was your horse doing? Was he going wild in the pasture, or was he ankle deep in mud? Maybe he needs a more controlled turnout situation or drier footing. Does he forge? In forging, the hind feet overstep so that the toe of a hind shoe hits the front foot as it lifts off the ground. You may hear the sound of metal as the shoes collide.

A horse with a short back and long legs is more likely to overstep and take off a front shoe. You can’t change your horse’s conformation, but your farrier can help. For example, rocker toes on the front shoes will ease breakover and help the front feet get out of the way faster.

He’s sore after shoeing.

As a rule horses are not sore after shoeing. If yours is, talk with your farrier to figure out why. A horse can be pinched or “quicked” by a nail that’s too close to sensitive tissue in the foot--something that can happen no matter how careful your farrier is. (A “hot” nail needs to be removed and your horse’s foot poulticed. A check by your veterinarian is always a good idea.) Your horse may also be sore if he was trimmed short of if the farrier had to do alot of corrective trimming.

Sometimes a horse with joint problems is sore just from having his legs held up while the farrier works on his feet. If your horse is routinely sore after shoeing or if the soreness lasts more than a couple of days, have your veterinarian look at him. This shouldn’t offend your farrier, who should be able to work with the veterinarian to solve the problem. If you can get them both at the barn at the same time to look at your horse together, that’s even better.

Hoof Health
The foot is the foundation of the horse, it’s often said--so if you want your horse to stay sound, start with a healthy hoof.

Feed his feet: The most important factor in hoof health is what goes into your horse. Nutrition is key to hoof condition, although the roles played by specific nutrients aren’t well understood. Good commercially formulated feeds seem to be all that many horses need, but if feet are weak or cracking then supplements may help. High-quality hoof supplements are usually blends of nutrients such as biotin and other B vitamins, amino acids, fatty acids and minerals such as zinc. It’s often hard to be sure a supplement is helping because it takes months for a new wall to grow in, but you may see deterioration when you stop feeding it.

Control his environment. Your horse’s feet can tolerate a range of ground conditions. But if he is constantly out in muddy or boggy ground, his feet tend to soften and become shelly, so the horn easily cracks and flakes. He needs to move to drier ground or spend more time in a dry stall.

Give hands on care. A daily check and cleaning wards off common hoof problems like thrush, a bacterial infection that takes root in the crevices of the frog. It also helps catch loose shoes and inquiries promptly.

Go easy with oil. Most horses don’t need any sort of hoof dressing. If your horse gets frequent soapy baths, you may want to protect his feet with a sealer because the shampoo strips natural oils from the hoof wall. (Plain water isn’t as damaging.) Very dry feet may benefit from oil; but you want the feet to be hard, and too much oiling can make them soft and mushy.

Stay on schedule. Have your horse’s feet trimmed and shod regularly. No matter how good your farrier is, your horse’s feet won’t stay in good shape if you let them grow too long between trims.

Outside and Inside of the Foot
Think of the abuse your horse’s feet take, handling massive amounts of stress as he gallops, jumps and turns. Luckily, the foot is a masterpiece of engineering, built to absorb shock and support weight. The outside--the hoof--is an armorlike shell made of tough protein, like your fingernails but many layers thick: The wall is the sturdiest part, thickest at the toe and narrowing gradually along the sides. It grows down continuously from special tissue in the coronary band, at the top of the hoof. The thinner sole grows from similar tissue that lines the bottom of the foot.

At the heels the wall takes a sharp turn in on each side to form the bars of the foot, two distinct ridges that you can see on the sole, running back toward the toe. Between the bars is the v-shaped frog. The wall, bars and frogs are the main weight-bearing surfaces, and their design helps the walls to expand slightly under pressure, absorbing shock. The exterior protects critical structures inside: The wedge-shaped coffin bone (also called the pedal bone, third phalanx, or P3) lies behind the dorsal wall--the hoof wall at the front. Two flexible wings, the lateral cartilages, reach back from this bone along the sides of the foot. The small pastern bone (second phalanx or P2) sits atop the coffin bone and links it to the long pastern (first phalanx or P1) above.

The navicular bone (distal sesamoid) is tucked behind the first two.

Two major tendons are anchored in the foot. The digital extensor tendon runs down the front of the leg and attaches to the upper front of the coffin bone. Its job is to straighten and extend the limb. The deep digital flexor tendon (DDFT), which runs down the back of the limb and helps bend it, attaches to the bottom of the coffin bone. At the heel, where it passes over the navicular bone, its fibers fan out. When your horse weights his foot, the force comes down through the small pastern bone and disperses through the navicular bone to the heel and through the coffin bone to the toe. At the heel, the DDFT stretches taut, helping to support the bones. The digital cushion, a thick pad of fiber and fat between the lateral cartilages, flattens under the pressure, pushing the sides of the hoof out a bit to absorb the pressure. Over the front surface of the coffin bone is a thin layer of tissue with thousands of hairlike projections, the sensitive laminae. They interlock with similar projections on the inner surface of the hoof wall, the insensitive laminae, to anchor the wall firmly to the bone.

Rodney King has been staff farrier at Rood and Riddle Equine Hospital in Lexington, Kentucky since 2008, working alongside Dr. Scott Morrison and other members of the clinic’s podiatry team. Previously, he ran a successful shoeing business focusing on competition and sporthorses in his native New Zealand. He is a Certified Journeyman Farrier and an Associate of the Worship Company of Farriers in England.

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