The Science of Horse Racing: Hooves and Horseshoes

July 20th, 2022

We define so much of our world by our feet.

Whether standing on two feet or four, the way that we interact with our environment comes from how we move through it. To be at our best, we must care for these important parts of our bodies, with part of that care coming in how we protect them. For humans, shoes fit the movement; running, jumping, sliding, whatever the tasks, we have footwear for it. Our equine friends, on the racetrack and off, are no different. For every pursuit is a shoe fitted to both the competitor and the competition. To understand how that works, we must understand a horse’s hoof and what goes into protecting them.

For this month’s the Science of Horse Racing, let’s play some horseshoes and learn a little about hooves, plates, and more.

Building Blocks

For a thousand-pound animal like a horse, so much depends on four feet that average only four inches in length. Though a hoof appears to be straightforward on the surface, there is more to it than what you see on the outside. To understand this important part of a horse’s body, let’s look at its interior and exterior structures.

The hoof starts with three bones: the coffin bone, the pastern bone, and the navicular bone. The coffin bone is the largest bone, located near the toe, and provides the structure that shapes the hoof. This bone is nestled inside the tissues that make up the hoof wall and the sole. Behind it is the short pastern bone, which connects the hoof with the longer pastern bone in the bottom part of the leg. Nestled beneath both is the navicular bone, also known as the distal sesamoid bone, which helps stabilize the coffin bone and helps keep the tendons that move the foot in place.

Protecting the interior structure of the hoof, including those bones, is the hoof wall, a solid, hard structure made of keratin. A horse’s body is continuously growing new, so this wall must be trimmed or worn off to keep the hoof at optimal health. Usually black or white in color, this wall does not have any nerves or blood vessels; when a farrier nails on a horseshoe, the nails are inserted at an angle into the wall. Since this part of the hoof has no nerves or blood flow, the horse experiences no pain from this process.

Where the hoof meets the leg is the coronet band, which contains a large supply of blood vessels for this part of the body. This area also sees the majority of the growth for the hoof, and, when damaged, can interrupt the cycle of development and renewal.

On the underside of the hoof, within the hoof wall, is the sole. This part of the hoof never touches the ground, running from the wall back to the frog. The frog is the V-shaped rubbery growth at the back of the foot that distributes the force of impact as a horse moves. It also contains a significant number of nerves as well as blood vessels, making it one of the most important parts of the hoof to keep healthy.

The anatomy of the hoof becomes more complex as we get deeper into the interior and exterior structures. For a discussion of horseshoes, though, this basic look should provide enough of a background to understand the purpose behind shoeing a horse as well as the choices farriers and trainers make when determining the type of shoe an individual horse needs.

The Right Equipment

Long before the modern racehorse was fitted with aluminum plates, early Asian horsemen fitted their horses with leather booties to protect their feet. The Romans next crafted leather and metal shoes for their own mounts and workhorses. By the 13th century, iron horseshoes were widely available, with blacksmiths becoming a necessary craftsman within a civilization increasingly dependent on horses. The first patent for a machine capable of mass-producing horseshoes came in 1835.

In the 21st century, we are less dependent on horses for day-to-day tasks, but we still regard them as important parts of our sporting lives. With those kinds of specialized pursuits comes shoes that help optimize their performance, and the men and women who put on those shoes and care for a horse’s hooves are called farriers.

Becoming a farrier involves a specialized education that not only teaches how to shoe a horse but also how to trim hooves and other care tasks necessary to optimize this vital part of a horse’s body. In the United States, those interested can attend a farrier or shoeing education program or apprentice to an experienced farrier to learn the trade. They can also specialize further, if they like, and focus primarily on shoeing for a particular discipline, like racing or other equine sports.

Farriers will determine what type of shoe a horse needs based on information from those caring for the horse as well as the horse’s job and other factors. Their first option is the basic horseshoe follows the shape of the hoof, with grooves that also contain holes for the nails. A rim shoe has a deeper groove through the middle, allowing horses to get more traction. These are typically used for barrel racing and roping, as they contribute to the quick turns and speed those sports require.

A bar shoe has a bar running across the back of the shoe where a gap would typically be; these provide extra support on that back portion of the foot, which might be necessary for treating an injury. Depending on the type of injury, the bar may be thicker or thinner or the shape of the shoe itself may differ from basic horseshoes to help remedy whatever ailment a horse may have.

Racehorses are typically shod with shoes made of aluminum, which are lighter than the basic steel horseshoe but are also less durable. Since most horses will compete once a month or so, they will typically be shod every 30 days. Depending on the surface a horse competes on, farriers will put on the appropriate shoe for gripping that surface. If a horse is scheduled to run on dirt and the track comes up muddy, a farrier can add modifications to the shoes to help the horse get a better grip on that surface. The same goes for horses that compete on grass; they will run with the shoes that give them the best chance to take hold of the surface and perform.

The purpose of horseshoes at the most basic level is to protect a horse’s hoof while they work. A sporthorse that is dancing around the dressage ring or jumping over obstacles will need a shoe that differs from their racing brethren. It is vital then that they not only wear the right shoes but also that those shoes are fitted properly. A visit from the farrier can go a long way to making sure a horse is comfortable and prepared for the task ahead of them.

Shoes and Slips

While not every horse needs to wear shoes, the wear and tear of work — whether it is a heavy Clydesdale pulling a wagon or a lithe Thoroughbred flying over the turf — means that most horses will need some sort of protection for their feet. Understanding the structure of the hoof and the needs of the individual horse adds another dimension to our knowledge about the horses we see every time we are at the racetrack.

Next time you hear about your favorite Thoroughbred dealing with a quarter crack or other hoof issue, think about the next visit from the farrier and what type of shoe might be required for recovery. Along those same lines, when the rains come at the racetrack, listen for the announcement about shoe changes. That information might make all the difference when it comes time to place your bets.