Horses evolved to run. That’s why your horse has the legs of a runner.
To survive, they needed to run fast, and this was the driving force of their evolution.
Your modern horse walks on just one digit (toe), where her ancestors walked on as many as four toes.
If you look at your own hand, your horse’s hoof is the same as the tip of your middle finger: from the last joint to the tip of your finger, to be precise.
The whole structure of your horse’s leg (and her cardiovascular system) has developed to support your horse walking on her “tiptoes”.
With long limbs constructed of fewer bones, your modern horse has a long stride and can cover a lot of distance in a short time.
The muscles and tendons in the legs store elastic energy (like a bow) and propel the horse forward with the least amount of energy spent.
This allows horses to run long distances without expending a lot of energy, relatively speaking, of course.
Let’s start with the basics of horse hoof anatomy.
Understanding the parts of the hoof, being able to label the right parts and understand their functioning is essential in order to understand what makes up “healthy” hooves.
The outer wall of the hoof is divided into three sections: the toe, quarter and heel.
It’s a good idea to understand how these areas look from different perspectives because when you pick the hoof up, you’re looking at the palmar surface of the horse (the ground side) and your view is essentially upside down.
Now, let’s get more acquainted with the parts of the horse’s hoof.
Heel bulbs: soft horn tissue with a cushion of connective tissue on the interior side, providing the bulbs with springiness and flexibility. The bulb’s corium produces a delicate, pliable horn, and this horn contains a large amount of water and sweat glands.
Heel buttress: the “platform” on which the hoof lands. Without a solid landing platform, the rest of the hoof cannot function properly and can be damaged irreversibly. The heel buttress extends into the foot to form a solid ‘buttress’.
Frog: forms a “V” into the centre of the sole and is a major functioning part of hoof health. The frog is the shock absorber as well as the energy dissipator of the hoof. It is dynamic and changes in response to terrain, diet, and other hoof demands. The width should be about 50-60% of its length. Thrush is an infection which turns healthy frog into a necrotic, infected, black, slimy horn – the bacteria rots the frog as it’s the softest and most flexible horn on the horse’s foot, so make sure that you know what a healthy frog looks and feels like. If your horse’s frog is not fully functional, your horse’s health will suffer.
Central sulcus of the frog: a small indent, about the size of a thumb. There should be no cracks showing infection and/or contracted heels. This can predispose the horse to lameness if not addressed correctly.
Apex of the frog: the tip of the frog. The portion closest to the apex should be substantial enough to touch the ground when the horse is bearing weight. If the frog is not touching the ground during hoof loading (when the horse is placing weight on the hoof), the rear of the hoof will not develop properly and be weak.
Hoof wall: the part of the hoof which is visible when the horse is standing. It covers the front and sides of the coffin bone. The wall comprises the toe (front), quarters (sides) and heel (back). The hoof wall should be smooth, a bit shiny, and free of prominent rings. It should also not not exhibit any cracks, chips or flaring. The hoof wall protects the entire foot inside the capsule and should be of uniform thickness, about +1 cm (1/2 inch) thick, corresponding with the thickness of the sole of the hoof.
White line: is a white-yellowish line around the inside of the hoof wall that connects the wall of the hoof capsule to the inner foot. This area should be solid with no separation, so that dirt, mud and environmental insults are not allowed into the foot. Any hoof trimming should respect the white line and the toe should never be brought back further than halfway through the white line because the outer edge of the white line is not sensitive, but the inner half of it is. Taking back the toe so much that it cuts into the sensitive part of the white line can cause some sensitivity or lameness, just like cutting your own toenails to the quick would.
Bar: provides traction and support for the back of the hoof, preventing the hoof from over-expanding during landing, as well as acting as “skid brakes”. The bars should never be “dug out” but “skimmed” down to sole level. Note: some protrusion of the bars is favourable in wet or slippery conditions, so even “skimming down to sole level” may not be the best trimming. On the contrary, they should never be allowed to become so overgrown that they fold over and form another layer of horn over the sole.
Collateral groove: should range between 1,6 – 3,2 cm (2/3 – 1 1/4 in) deep from apex to heel, and should be clean and free of thrush. Under the apex, the collateral groove should be about 10-15 mm deep (2/3 in) as the coffin bone sits just on top of the apex at about 1,2 cm (1/2 in) in the foot. A collateral groove more shallow than this could be a sign of thin soles, which is going to cause the foot to be inadequately protected from environmental abuses. Any less than 2,5 cm (1 in) depth at the back of the foot, under the seat of corn, indicates low heels. Low heels and thin soles are indicative of hoof collapse, which causes lameness.
Seat of corn (also known as corns): a corn is a bruise that forms between the sensitive and insensitive layers of the sole of the foot. The ‘seat of corn’ is the most commonly affected area. It is located between the hoof bar and wall, near the heel. Corns do not always cause lameness, and if they do, the lameness is usually not severe.
Toe & point of breakover: The toe helps protect the inner foot and the circumflex artery that runs around the edge of the coffin bone. The toe should be short enough that the breakover during the hoof lifting off the ground is quick and does not “drag” on the toe. When you’re holding your horse’s hoof and looking down at the bottom of it, consider the point of the toe to be 12 o’clock. The breakover of the toe should be from 10 o’clock to 2 o’clock. This area, covering about 2,5 cm (1 in) from the tip of the toe towards the apex, is known as the toe callus.
Coronary band: the junction between the hair-producing skin of your horse’s lower limb and the hoof wall. The outermost layer of skin on the coronary band is a lifelong cellular proliferating zone, meaning that it’s always producing new cells. As these keratinocytes undergo maturation and eventual death, they form the middle of the horn of the wall. This constant adding of cells in the coronary segment causes the middle layer to move downward to reach the ground – this means your horse’s hooves grow by 6-8 mm every month on average. Exactly how much the hoof grows is affected by internal and external factors. It takes 8-12 months for a completely new hoof to grow from the coronary band to the ground.
Periople: responsible for producing the outer shiny layer of the hoof wall. This outer layer prevents moisture loss from the inner layer of the hoof wall. It also stops moisture from going into the inner layer. You can see the periople itself as the thin membrane that grows from the outer edge of the coronary band and down the hoof wall, and in most healthy feet the periople can be seen growing as much as a third of the way down the hoof wall.
Growth rings: externally visible ridges in the hoof wall that show differences in the rate and quality of growth of the hoof wall. Growth rings can show problems within the hoof capsule, or simply be an external map of changes in nutrition, activity, or a systemic disturbance that has altered the hoof growth at some point in time.
What is the hoof mechanism?
When a hoof is loaded with the weight of a horse, it is pushed down and expanded.
This function acts as a shock absorber as well as pulls blood into the internal structures of the hoof. When the weight is taken off the hoof, the structures contract back into their original form and push the blood back into the bloodstream.
For a fully working hoof mechanism, there needs to be frog pressure.
The frog covers a structure called the digital cushion (the main shock absorber inside your horse’s hoof), which is full of blood vessels.
When the horse loads the hoof with weight, the ground pushes up against the frog, which in turn compresses the digital cushion. This pressure pushes the blood out of the digital cushion (like when you squeeze a sponge and all the water comes out).
When the horse then picks up that foot to take another step, removing the pressure, it causes the blood to rush back into the digital cushion (imagine putting the sponge you’re squeezing into a bucket of water and then releasing it once it’s under the water, so that the sponge fills up quickly with water).
Blood is expelled from the digital cushion under pressure and pulled into it during release, thus supporting the function of the circulatory system.
When your horse has four fully functioning hooves pumping blood to help the heart, your horse will be much healthier and live longer.
The hoof mechanism needs certain conditions to work correctly:
1) the frog must be healthy and able to support the full weight of the horse (this means the foot needs to be free of disease and infection),
2) the hoof wall must allow for expansion and contraction (shoes and surfaces can decrease the hoof mechanism),
3) the hoof needs to be balanced correctly (the hoof trim needs to allow the whole sole and the edges of the hoof wall to make ground contact).
Why is the hoof mechanism so important for your horse?
Horses have a relatively small heart and make use of the hoof mechanism to effectively pump blood in and out of the legs.
The hooves — when functioning correctly — serve as heart-supporting circulatory pumps that push the blood back up the leg, helping the heart to work against gravity.
This allows for less stress on the heart, lower heart rates, and faster recovery after exertion.
A weakened circulatory system can cause an overstressed heart, decreased or insufficient blood flow throughout the body, and decreased performance because of oxygen not being effectively carried to the working muscles and waste products removed from them.
A constant and effective circulatory system is essential to maintaining general wellbeing, heart health, as well as leg and hoof health.
No hoof, no horse!
It’s a common saying in the equine world, and it means that you cannot have a healthy, functioning horse without sound hooves.
Knowing hoof anatomy and care is important, because it will help you recognise problems and find the right solutions.
Knowing your horse’s hooves will help you recognise a good farrier from a bad one and save your horse from unnecessary problems and pain. It’ll also help you communicate better with both vets and farriers when you are confident in your understanding of the basic building blocks of your horse’s wellbeing.
Keep in mind that even an experienced farrier or hoof trimmer can make mistakes if the horse is not standing still, so train your horse to stand for treatment even for longer periods of time.
To shoe or not to shoe?
Horses can be shod or unshod. Shoes help protect the hooves in conditions that can cause breakage or excessive wear.
There are also shoes that increase traction — such as when walking on icy roads that are slippery — or alter the gait of the horse for corrective of aesthetic purposes.
Shoes are made of different materials, from rubber to steel. The size, shape and thickness of the shoe will vary to suit the needs of the individual horse.
Unshod horses will develop a hard hoof that is durable, provided that their hooves have been maintained properly. Barefoot horses can traverse just about any surface a shod horse can, and can wear protective hoof boots when necessary to prevent soreness and injury.
Hoof boots are a temporary protection for the hooves and can easily be put on and taken off by the rider (again, remember to train your horse for hoof boots!).
Both barefoot and shod hooves need to be trimmed regularly because domestic horses rarely live in the kind of conditions that naturally wear down and condition the hooves (like wild horses’ hooves).
A horse can transition from barefoot to shod by having the shoes pulled, however, this takes time, resources and knowledge to be successful. The hoof needs the right conditions and enough time to recover and re-grow after being shod.
Does your horse need horseshoes?
There’s a lot of debate, especially online, about whether horseshoes are really necessary.
Domestic horses that are kept in conditions that don’t meet the species-specific needs of the horse are more dependent on horseshoes.
Depending on the type of work, diet, carry load, exercise amount and surfaces the horse travels on, it needs differing protection for the hooves.
Some horses need shoes all year round, some only part of the year (such as in icy conditions during winter) and some don’t need shoes at all.
All horses need their hooves protected.
Whether that means shoes or barefoot management, proper and species-specific hoof care is essential for a healthy hoof, shod or unshod.
So, rather than wondering if your horse needs shoes or not, think about what your horse’s hooves require right now.
Are the hooves getting what they need to function as intended? And what can you do to make sure your horse’s hooves are healthier than they were yesterday?