“No foot, no horse” is true for any horse in an athletic career. Owners and riders often wonder if their horse is shod properly or how to tell whether he is or isn’t. Stephen O’Grady, DVM, MRCVS, of Virginia Therapeutic Farriery, says that knowing the basic principles of farriery can be helpful. “If you consider the anatomy of the foot, biomechanics and the principles of farriery, you can come up with a good concept of how a certain horse is or should be shod,” he says.

“Textbooks for veterinarians and farriers describe the normal foot, but we don’t really know what a normal foot is,” says O’Grady. What’s normal for one horse may not be normal for another.

Guideline 1: Hoof–Pastern Axis

“We must take breed into consideration, the ground the horse travels on, use of the horse, etc., but we can implement guidelines regarding what is considered a good foot,” O’Grady says. 

To start, reviewing a brief anatomy lesson of the bones that make up the pastern and hoof is helpful: The three bones of the horse’s digit are the long pastern bone (the proximal phalanx), the short pastern bone (the middle phalanx) and the coffin bone (distal phalanx). The horse’s cannon bone (third metacarpal) and the long pastern bone form the high-motion fetlock joint (metacarpophalangeal joint). The long pastern and the short pastern bones form the low-motion pastern joint (proximal interphalangeal joint). And the short pastern bone, the coffin bone and the navicular bone (distal sesamoid) form the coffin joint (distal interphalangeal joint). Furthermore, the hoof capsule is defined as the wall, sole, frog and the bulbs of the heels.

“If we stand the horse on level ground, we want a straight hoof–pastern axis. If you draw a line through the bones of the digit to the ground, it will form a straight line,” O’Grady says. “This also creates a straight line on the surface of the pastern and the dorsal (front) surface of the hoof capsule, which is important for any horse.”

The hoof–pastern axis affects the position and angle of the coffin joint. “Weight is borne most efficiently when it goes through the middle of the joint rather than in front or behind the center of the joint if the angle is out of alignment,” he adds. 

“Secondly, with a straight alignment, the bottom of the coffin bone is parallel to the ground so the entire bottom of the bone bears weight. If a horse has low heels, the bone is tipped up at the toe; more weight is on the back of the foot. If it’s a club foot, the bone is tipped in the other direction with more weight on the toe. A straight hoof-pastern axis provides a good relationship between the bottom of the bone and the ground,” says O’Grady.

Guideline 2: The Bottom of the Hoof 

“Next, we look at the middle of the foot from the bottom—the widest part. You can actually measure it and then know that the center of rotation will be a few millimeters behind that point—toward the back of the foot,” O’Grady says. The center of rotation is a guideline used to find and maintain a proportional foot, as well as distribute weight and stress evenly. “The center of rotation is our starting point for biomechanics and also for the trim. If we draw a line across the widest part of the foot, we know where the center of rotation is and strive to have approximate proportions (though not always equal) of ground surface on either side (front to back) of the middle of the foot. The proportions are important so that weight bearing is distributed evenly on either side of the center of rotation.”

An owner, vet or farrier can look at the bottom of the foot and draw an imaginary line with the eye across the middle of the foot and visualize those proportions. “Two of the biggest issues we see with proportions are long toes and/or heels not trimmed appropriately and short shoes.” This will change those proportions on the ground surface. 

Guideline 3: The Slope of the Coronary Band

To further determine if the hoof has good conformation, look at the hoof from the side and assess the slope of the coronary band. “It should go from toe to heel with a nice, gentle slope. If the coronary band approaches horizontal, the heel is too high (club foot). If the coronary band forms [a severe] angle from toe to heel, nearly to the ground, it’s a low heel,” says O’Grady.

Looking at the horse from the front, standing on flat ground, a line through the coronary band should be parallel with the ground. If the coronary band slopes to one side or the other, the hoof wall on one side is too high or low.

“If you look at the horse from behind and get down low enough to look at the heels, often there will be one foot with high heels and one with low heels. This is a common problem in sporthorses called mismatched feet. Looking at the height of the heels on each foot from behind, if the coronary band on one side is a different length and higher than the other, this is termed a sheared heel, which means the horse is overloading one side of the foot. The farrier should look at the whole horse and assess hoof conformation before he or she starts trimming and shoeing.”

Additionally, one of the first things a person looks at when picking up the foot is the frog. “If the horse does not have a healthy frog, it’s not a healthy foot. Defined, the hoof capsule consists of the wall, sole, frog and the bulbs of the heels. Therefore, if any one of those structures is abnormal, or not healthy, it affects the entire hoof capsule. A horse with any kind of hoof capsule distortion, such as club foot, long toe–low heels or sheared heels, will have a compromised frog,” he says.

In hind feet, there are additional problems. “The low-heeled, bull-nosed conformation, where the dorsal hoof has a rounded or contour shape in the hind feet, is all too common in show horses, and can affect performance,” he says. This hind-foot conformation places excessive weight bearing on the heels leading to discomfort and lack of propulsion.

Guideline 4: Watch the Horse in Motion

After evaluating the hoof when the horse is standing still, watch the horse in motion. “When a horse walks on a firm, level surface, he should have a slight heel-first flat landing. If he lands markedly heel-first, with a toe flip, either the heels are not trimmed appropriately and/or he’s wearing a size smaller shoe than he needs, which decreases the ground surface area of the foot,” says O’Grady. A marked heel-first landing puts extra load and concussion on the heels and related soft-tissue structures, and this concussion travels up the leg.

“Toe-first landing is definitely abnormal. When this occurs, the horse may have pain in the heels, thus avoiding the heel area, and lands on the toe or has a shortening in the muscle–tendon unit in the leg above, which won’t allow the heels to reach the ground during the stride. These horses usually have a higher heel as they try to compensate for shortening of the muscle-tendon above,” says O’Grady.

Conformation Factors

How a horse loads the foot is dictated by limb conformation. In motion, looking at a horse from the front or back and observing how the foot lands, some hooves will land asymmetrically. If you look at that horse from the front, he may have a narrow chest, with the front legs rotated outward. “When he breaks over, he breaks over toward the outside and then the foot has to swing in on an arc and doesn’t allow the foot to land flat. Generally, they land on the outside of the foot and then load the medial [inner] side. If the horse lands asymmetrically, he will have a sheared heel on the overloaded side.

“Yet some farriers think a horse should land flat when looking at them from the front or back. If you attempt to make a horse land flat, you are going against that animal’s conformation [which puts excessive stress and strain on some other parts of the leg]. There are numerous ways we can compensate or manage these horses that land asymmetrically, but we don’t want to make them land flat if their conformation dictates otherwise,” he says.

“Those scenarios are readily distinguished as the horse walks, before the farrier starts to trim the foot, and the combined observations should influence how that horse is shod,” says O’Grady.

How Much to Trim

Shoeing any horse is all about the trim. “The heels should be trimmed to the base of the frog, if possible, so all the structures in the heel share weight-bearing. When you put a rasp across the bottom of the hoof at the heels, it should touch all surfaces on both the frog and the heels. My goal is simply to trim the heels so the frog and the hoof wall at the heels are on the same horizontal plane. In most cases, we can attain that goal,” says O’Grady.

“With some horses, however, you can’t trim the heels that far back because there’s not enough hoof wall or the frog has prolapsed toward the ground. If the frog is located below the wall, we may remove the shoes for a few days so the horse can stand on the frog and reposition it,” he says.

“Some people feel you should not trim the heels, thinking it will make them lower, but it doesn’t. Heels continually grow forward, and the horse loses ground surface on the bottom of the foot. Heels don’t grow tall; they grow forward,” O’Grady adds.

“We tend to over-trim sporthorses. When winter show season starts and horses go to Florida, they’ve usually had a little time off before they arrive and sometimes the shoes were pulled off for a brief period.” This allows the heels to relax, grow and expand, which will improve function and improve the foot conformation.

“However, when the show season starts, horses are shod with pads, impression material, etc. As the horse goes through the season, the work increases, and he is shod every four weeks. The horse will start to lose hoof mass from the increased work combined with continual trimming,” he says.

It may be better on alternative resets to just shape the foot a little, leave the mass on the bottom of the foot and put the shoes back on, instead of trimming every four weeks. “At the next reset, we might need to trim a little more, but we usually don’t give these horses enough time to regrow what we take off, and the horse has less sole. If the soles are getting a little thinner by the end of the season, that’s the time to use a pour-in or put pads on for extra protection, not before,” O’Grady explains.

The Effects of Footing

“Most competition horses work on deformable surfaces [surfaces that change their shape] or synthetic footing. This is usually sand-based with different materials added,” O’Grady says. The footing a horse will be working on is often taken into consideration by the farrier in determining how to shoe the horse.

“Synthetic footing can be too soft or too hard. If it’s too hard, there will be too much concussion when the foot lands, and we have to protect the foot a little more to minimize that concussion. If footing is too deep, the foot sinks in more and puts stress on soft tissues above the foot. Footing can be too deep or too loose,” he says.

“When the foot lands, it slides for a few milliseconds. If footing is too hard or the shoe has too much traction, it stops the foot abruptly. If footing is too loose, the foot slides too much. When footing is too loose, it affects the foot when it lands, bears weight and breaks over. There’s not enough grip to allow the toe to propel the horse forward,” O’Grady says. Loose or very soft footing affects the slide when the foot lands and also affects the horse when he’s turning sharply.

Footing at various competitions may be different, and often arrangements are made to have the horse reshod to try to match the footing. “If the footing is soft, the farrier will use shoes with a ‘flotation’ effect and more surface area like a bar shoe, spider plate or a shoe with wide branches to keep the foot on top of the surface,” he explains.

“A three-day event horse will be on synthetic footing for dressage and show jumping, but cross-country might be grass—and that’s where the farrier may use traction devices or slip a pad between the foot and the shoe to protect it,” says O’Grady. The shoe is adjusted to compensate for different surfaces. The shoe itself forms a rim around the foot with the sole forming a cup, which creates more traction. 

Other Issues

“One of the issues with sporthorses is shoeing intervals. Sometimes they are let go too long and sometimes they are shod too often. The optimal interval for farriery would be four to six weeks,” O’Grady explains.

It also helps to know the horse and have a feel for what’s right for that horse. A good rider is in tune with the horse and can tell if something is a little off. “If an accomplished rider or trainer tells the vet or farrier the horse is not right, they need to pay attention. The rider can feel things we can’t see,” O’Grady says. 

“Many things can be done with farriery, but we all need to be working together on the same page,” he adds. Vets, farriers, horse owners and riders need to evaluate the horse together, using guidelines that apply to any horse’s foot. “These guidelines can be used for evaluation and to apply appropriate farriery,” he says. 

“If a horse is well shod and has strong, comfortable feet, he will last a lot longer and be able to perform at the top of his game and is less likely to have lameness problems,” O’Grady says. It’s important to talk with the farrier and know why the horse is being trimmed or shod a certain way.

About Stephen O’ Grady

Stephen O’Grady, DVM, MRCVS, of Virginia Therapeutic Farriery, focuses on foot disease and equine therapeutic farriery. He combines his skills as veterinarian and farrier to better understand and treat problems of the foot. O’Grady has written book chapters and many peer-reviewed papers in veterinary and farriery literature. His career has been devoted to competition horses and farriery. He maintains an informational website devoted to footcare and therapeutic farriery: www.equipodiatry.com.

This article originally appeared in the Winter 2024 issue of Practical Horseman.