A Writer’s Guide to Horses Part VII

Horse people are occasionally surprised that horses remain a viable species. They’re subject to as many illnesses as any other species, and some individuals require very specialized care.

*Cover photo courtesy of the author

The most common health problem in horses is lameness, so we’ll start with care of the hooves. A horse’s hoof is made of keratin, like your fingernails, and can vary in hardness. There’s a disagreement between scientists, who study horses; and farriers, who shoe horses, as to whether the color of a horse’s hoof correlates with strength. Horses can have black or white hooves, usually according to the color of the skin on their lower legs, and many people have noted that black (actually more like dark gray) hooves are stronger and less likely to crack. They’re also harder to shoe, in the sense that it takes more strength to trim and file the hoof evenly, and to drive nails into the hoof wall.

The internal structures of the hoof are as complicated as any human organ system, so I’ll leave you with the basics. The outside of the hoof is called the hoof wall. It has no nerve endings; this is the part that the nails are driven through when the horse is shod. The coronet band is the other major visible structure; it’s the juncture between the hoof wall and the horse’s pastern (ankle). It’s the source of hoof wall growth, and an injury to the coronet band can cause the horse’s hoof to grow odd ridges for the rest of its life. The hoof wall takes between eight and twelve months to grow out fully, so it’s possible to see if the hoof wall was recently injured by visual inspection.

horse hoof diagram

*Diagram courtesy of the Equine Podiatry Association UK

When viewed from the bottom, the hoof has a few major structures. The most visible is the frog, which is a v-shaped mass of tissue that helps circulate blood back up to the heart. It is partially weight bearing and has some nerves that are well protected by the callus that is in contact with the ground. The slightly concave bottom of the hoof is called the sole; it is not weight bearing. The hoof wall takes most of the horse’s weight.

Wild horses, of course, never wear shoes, and some domestic horses go barefoot as well. Horse shoes are usually made of steel, and are nailed to the outer wall of the hoof using seven or eight nails, the points of which are then folded down and filed so the shoe holds on better and there are no sharp edges. Horses’ hooves grow continuously, like fingernails, and are trimmed by a farrier or blacksmith every four to eight weeks, depending on the strength of the hoof, which varies from horse to horse; and the terrain the horse is walking on. Wild mustangs never have their hooves trimmed, but they usually live in such rocky areas and have such poor nutrition that their hooves stay short.

An unshod horse walks surprisingly quietly, only a little louder than a walking human. There’s no ‘clink,’ of the shoes, and not enough concussion to produce the ‘thud’ sound that you hear when it’s trotting or cantering. Shod or unshod, a horse will crunch when walking on gravel. An unshod horse can make a dull clip-clop or pattering sound on pavement, depending on the shape of its hooves. Yes, really. A horse’s hoof is slightly concave on the bottom, and the deeper the cavity, the louder the noise it makes. If the horse is shod, it’s louder on pavement, stone, or gravel, and it’s possible to tell if a horse needs new shoes by making it walk on pavement; the loose shoe will make a sort of ‘cli-ink’ sound when it hits the ground. Hard to describe, but very distinctive, and useable to a writer in all sorts of situations.

A horse’s hoof isn’t quite unique, but closely related horses often have similarly shaped hooves, which makes sense because conformation and gait are heritable, so it’s logical that the hooves would wear down in a similar way. Your hero of the Old West might recognize a familiar horse by the shape of its hoofprints, and make himself seem like a god of horsemanship to readers.

A horse’s front hooves make a rounder hoofprint than their hind hooves, which tend to make a narrower or slightly triangular print. This is partly due to the differences in leg attachment- a horse’s hind legs tend to splay outward, so the inside of the hoof is worn down further- and because a horse carries more weight on its front end. Over time, this causes the hooves to flatten out slightly, especially if the horse isn’t shod. Because of the variation in hoof shape, shoes are differently shaped. It’s important that the shoe conforms to the hoof wall, and not the other way around; if the shoe is too small, the horse’s gait will be affected; if it’s too large, the shoe may catch on an obstacle and be torn off of the hoof, possibly taking a chunk of hoof with it.

There are shoes made for ponies, light horses, and draft horses, varying in size from about 3 inches across to about 12 inches. When shoeing the horse, the farrier (or blacksmith; which is a less-specialized metal worker) compares the shoe to the hoof wall by touch and by sight, and hammers the shoe into shape for that individual hoof.

Most people will recognize an ordinary horseshoe, but there are some variations for horses that need extra support. For horses with weak heels, there are egg-shaped shoes. Some shoes have a bar across the top, about an inch from the heel. Some shoes have metal clips (actually a little half-moon of steel that folds over the outside of the toe) to help keep the shoe on. There are also specialized shoes for horses ridden in certain disciplines. Racehorses are shod with aluminum because it weighs less, reining horses have ‘sliders’ on their hind feet to help them do a better sliding stop, and foxhunters often have studs screwed into the bottom of their shoes for use as cleats. Horses in icy conditions are often left barefoot, because snow and ice is less likely to pack into a barefoot horse’s hooves, but if the horse must be shod, the blacksmith can weld a strip of borium to the bottom of the shoe for extra traction. These shoes are often used in conjunction with a rubber pad. The pad is placed between the underside of the hoof wall and the shoe, and keeps snow and ice out of the hoof.


How to shoe a horse

Shoeing a horse is physically difficult. I’ve never done it, but I have trimmed a horse’s hooves, and it requires a lot of strength in the legs, back, and hands. Most farriers are men, for this reason, and though they can have long careers, injuries and damage to the body are common. Every farrier has a slightly different method of shoeing horses and dealing with recalcitrant ones, but the basic procedure is the same.

To shoe a horse, the farrier first removes the old shoe by cutting the clinches with a clinch cutter, then grasping it with the also aptly named pull-offs or shoe pullers, which look a bit like giant pliers. He then yanks on the shoe until it comes loose, which may take a few tries and require him to reset the pull-offs in different places on the shoe.

Once the shoe has been removed he can clean the hoof more thoroughly with hoof pick or hoof knife, then trim the wall, removing a shoe-shaped ring of hoof. Dogs love to eat these, for some reason, so if there’s a farm dog, he may try to abscond with the bit of trimmed hoof. Too much will make him sick, however. When the hoof is trimmed short enough- and each horse is unique in this regard- the farrier will file down any rough edges with a rasp. For a horse that goes barefoot, their pedicure is over; the farrier repeats the trimming and filing on each hoof, and the process is finished in fifteen or twenty minutes.

If the farrier is putting a shoe back on, he fetches a shoe or, in historical circumstances, makes one. Making shoes isn’t overly difficult if one has access to iron bars of standard size; the blacksmith heats the bar, hammers it into an approximate shape, cuts off the excess length, and uses an awl to drill seven or eight square nail holes in the shoe. Modern farriers can buy horseshoes in standard sizes, and hammer them to fit the individual horse. They might heat the shoe in a portable furnace before hammering; this is called hot shoeing; or they might forego heat in favor of muscle power; this is called cold shoeing. Both work equally well.

When the shoe fits, the farrier attaches it with nails. In the past, people used seven, because it was lucky, now most farriers use eight for a better hold. Horseshoe nails have a square head and are beveled on one side of the shaft. This helps the nail turn outward, away from the sensitive parts inside the hoof, so it’s very important that the farrier orients the nails correctly. If he doesn’t, the horse will be instantly and severely lame, because someone just did the equivalent of shoving a splinter under a human’s fingernail. If you, a writer, must cripple a horse, this is one of the fastest ways to do it.

Properly fitted, the nails come out the outside of the hoof wall, about an inch above the ground when viewed from the side. The sharp points are cut and the remaining exposed nail is folded down over the hoof wall with clinchers. This helps keep the shoe from falling off. Then all that remains is to run a rasp over the rim of the hoof wall, to get rid of any uneven spots, and watch the horse trot on a hard surface to be sure the shoe fits properly and isn’t affecting its gait.


Injuries of the feet and legs

It’s a rare horse that never suffers from any lameness, partly because that term is used to describe myriad conditions of the hooves and legs. Basically, anything that makes the horse limp. Lameness is usually caused by injury- anything from a stone stuck in the hoof to a bruise from uneven ground to a strain or sprain of muscle or tendon. A horse has eighteen bones in its foreleg, depending on how you count them (some of the bones fuse together as the horse ages), as well as a raft of flexor and extensor tendons and ligaments. There’s almost no muscle in a horse’s lower legs, so any blow to the legs is likely to damage something. Older horses are also subject to arthritis, and some horse owners give anti-inflammatory meds to keep the horse comfortable. In the past, such horses were retired from work or sometimes put to sleep if a retirement home could not be found for the horse.

A lame horse may not appear lame. Horses are prey animals, so they try to disguise pain or weakness. Most of them, anyway. Some are wusses, and some have learned to fake lameness to get out of working. But many lamenesses can be spotted by watching the horse trot on a hard surface. The trot is a two-beat gait, where the hooves fall in diagonal pairs. If the horse is lame, its stride will stutter consistently at the same point in the movement. The horse might also bob its head, that is, it will raise its head when the lame leg hits the ground.

Lameness varies in severity, so the horse’s recovery time will also vary. Sometimes the horse will be recovered in a day or two. But an injury like a bowed tendon (a sprain of one of the flexor tendons at the back of the horse’s lower leg; it’s characterized by a distinctive and severe swelling) can put a horse out of commission for months. Stone bruises can heal in a week, or they might turn into abscesses that make the horse lame for a while until the abscess bursts and relieves the pressure. But because they’re caused by injury, the usual treatment is to rest the horse. If the injury causes inflammation, a lot of horse people choose to ice the area to reduce swelling and pain. In the past, there were only two real treatment options: rest the animal, or euthanize it. There’s a joke among veterinarians that the treatment for nearly any illness in horses is to shoot the animal, because it does solve the problem. Nowadays, there are more options for bringing back a lame horse.

Lameness can also be caused by illness. I mentioned above that horses are subject to arthritis as they get older; this is the most common non-acute cause of lameness. Another well-known illness is laminitis, which is inflammation of the laminae, bristle-like structures that attach the hoof wall to the interior structures of the hoof. When a horse is under great stress, from overwork, pregnancy, metabolic disorders, or overeating, the blood vessels of the sensitive laminae can burst, allowing blood to pool in the hoof. It’s extremely painful, and a horse suffering from laminitis is easily noticed by its stance; it will lean back on its hind legs and allow its forelegs to splay in front of it, to relieve the pain. Laminitis is more common in the forelegs than the hind. It’s also known as founder, though properly speaking, founder refers to chronic laminitis. A foundered horse grows horizontal ridges on its hoof wall, and sometimes the interior bone of the hoof will begin to rotate downward and come through the bottom of the hoof. Coffin bone rotation usually spells the end for the horse; it will be in pain for the rest of its life and there’s no cure.

It used to be common to see a phrase like this in fiction: ‘They rode on until their horses foundered’. If you use this, readers will understand that the characters went a long way at a fast pace, but I might come through your computer and swat you upside the head. Founder is a chronic, longstanding illness; a foundered horse is unrideable long before anyone tries to escape atop it. Rather, a writer should say that the characters rode until the horses were stumbling, or that the horses finally refused to move, or they were lathered with sweat and breathing like a freight train. Misuse of the word is a small error in the grand scheme of things, but it makes me roll my eyes and think less of the writer.

For you, the writer, it’s usually enough to say that a horse is lame. The readers will understand that this horse isn’t usable, and if a character does try to make it do something, that character is either desperate or a villain. Your hero will let the horse rest, and find another one.


Other illnesses

Horses are subject to other health complaints, the most common of which is colic. Colic refers any sort of indigestion, which can be mild or quite serious. Horses are nearly incapable of vomiting; if they eat a foreign object or poisonous plant, it has to come out in the usual way. The intestines can also become blocked because the horse has consumed large amounts of sand/dirt along with its food, or by enteroliths (intestinal stones). Modern horses have the benefit of surgery, but colic surgery is a fairly recent practice (within the last fifty years or so) and some cases are so severe that it does no good.

A colicking horse will lie down and roll more frequently than usual, or sometimes nip at its belly. It’s very dangerous to allow a horse to roll when it’s colicky; it can tear the tissues that keep its intestines in place, and create knots in its gut. Without surgery, this is fatal. So a colicking horse should be made to walk around until it stops trying to roll. This can take a few hours. In modern times, painkillers can be administered, and some owners force-feed the animal large quantities of mineral oil to lubricate its intestines and get rid of any potential blockages.

Most horse owners take steps to prevent colic, because the prognosis (and the cost of treatment) is so unpredictable. So the horse’s living environment is cleared of poisonous plants like wilted cherry leaves, bracken fern, hemlock, locoweed, red maple leaves, yew, and black walnut (black walnut shavings in the horse’s bedding can also induce laminitis). Feed is stored securely and away from the horse; overeating is one of the most common causes of colic. And horses that live in sandy environments can have their food placed in buckets or plastic tubs up off the ground, so they don’t inadvertently consume sand with their food. Some horses are prone to colic; others go their entire lives in less-than-ideal environments and never have a problem.

As with all species, infectious diseases can be a problem for horses, and entire books have been written about causes and treatments. Most readers are familiar with rabies and tetanus, and horses can also come down with varieties of influenza- not known to be transmissible to humans- and a whole host of upper respiratory diseases and neurological problems. Vaccines are available nowadays for many diseases, but most are less than fifty years old. So, when your knight is shining armor is participating in a siege, you might consider mentioning that the horses, as well as the soldiers, are dropping like flies from disease.



Did you know that horses go to the dentist? They do, and sometimes for the same reasons as humans. Most horses don’t get cavities, because their diets aren’t high in sugar, but some need to have a tooth pulled or an abscess drained.

The most common dental work in horses is floating their teeth. This is the process of filing down the rough edges of the molars. Horses’ teeth are continuously erupting, like many species of rodent, and if the horse’s jaws aren’t perfectly aligned, the teeth can wear unevenly and develop sharp points on the front, back, or sides. As with most things horse-related, the severity of this problem varies. Some horses need their teeth floated every six months; others never have it done. Once a year is standard for domestic horses.

Usually, the horse is mildly sedated before the vet or dentist begins floating its teeth. A horse’s teeth aren’t as sensitive as a human’s, but the vibration can be unsettling, so a sedative such as dermosedan helps the horse to stay calm while allowing it to remain on its feet. Once the sedative takes effect, the vet/dentist inserts a speculum into the horse’s mouth and uses a float- a file on the end of a steel or aluminum rod- to file down the teeth, one side of the mouth at a time. Some dentists have an instrument rather like a cordless drill that can be used to the same effect. Floating teeth usually takes five to ten minutes once the horse is sedated; it’s not a complicated process.

The other interesting thing about a horse’s teeth is that they change regularly with time, and visual inspection of the teeth can tell a person the horse’s age. A foal’s baby teeth begin erupting shortly after birth, then fall out starting at about two years of age. When a horse is about five, it has all of its adult teeth; this is called a full mouth. Spots of color, called cups, appear and disappear at regular intervals on the wearing surface of the incisors, and a shadow called Galvayne’s groove appears on the side of the third/corner incisor at ten. Galvayne’s groove extends all the way down the tooth at twenty years and begins disappearing around twenty-five. It’s usually gone by thirty, which is about the time the rest of a horse’s teeth start wearing out.

Judging a horse’s age by its teeth takes practice, and you can signal that your hero is an experienced horseman by having him accurately do so. But there are some pitfalls. Horses that eat coarser food, or have a lot of dirt mixed in, can have more worn teeth than a horse that eats less abrasive food. And unscrupulous horse dealers used to file down a horse’s incisors to make the cups disappear, making the horse look younger and therefore worth more money. The practice is called bishoping; it’s hard to say how common it is or was.

Keeping a horse healthy can be simple or absurdly complicated, depending on the animal. And of course, it costs money. There are veterinary records dating back to the Middle Ages in Europe, where a knight shelled out shillings or even pounds of silver for veterinary care, which was no better than the medical care for humans at the time. And this was in a time when a laborer made four or five pounds a year. No matter the era, horse people love their horses, and take steps to keep them healthy and sound.

Next up: Feeding and housing your horse!


  1. Fascinating, actually. Thanks for this – all noted for future reference, as it’s been decades since I had to deal with a horse in the real world! The horse that we had for four or five years, that my mother taught us to ride was a retired parade horse, whose hooves were in a condition that he could no longer be shod, and had to be ridden only on dirt. Which was great – we lived in the back country, and all the roads around were unpaved. I remember the farrier coming every couple of months and trimming his hooves – don’t recall our dogs being especially interested. I also remember the chore of checking his feet and prying out any pebbles stuck there – but he was a very well-trained and gentle horse, and was quite cooperative.

  2. “many people have noted that black (actually more like dark gray) hooves are stronger and less likely to crack.”

    Same in dogs. Black toenails are stronger, less likely to break, and more readily stay worn into a functionally blunt shape, rather than developing long spiky points. It’s fairly obvious in a group of related dogs of different colors, and more so when an individual has nails of different colors. Especially if you’re the one wielding the nailcutter.

  3. The barn where I first rode in Flat State had a mare who would go lame as soon as she passed a certain mailbox. Amazing coincidence, that. And if you rode in a different direction, she’d try to go back to the barn. Failing that, the rodeo was on!

    I was not fond of that mare.

  4. What kind of scientists say that the different colors have the same strength?

    1. This isn’t my area of expertise, but from what I’ve been able to find out, the Romans had leather booties that they tied around the horse’s fetlock. Earlier civilizations might have used them, but it’s hard to find archaeological evidence for them. Around 900 AD, cast bronze horseshoes were being made and attached with nails, and by the time the Crusades kicked off around 1100, iron horseshoes were being made (iron is harder-wearing than bronze, so the shoes can be re-used if not too worn; the shoe is removed, the hoof trimmed, and the shoe reattached in the usual way).

      I’ve seen recreations of a weird-looking ‘horse sandal’ that was supposedly used by the Romans, but I’m skeptical because the design included a curved bronze spike that protruded upward from the horse’s toe, holding the laces in place. This would have been incredibly dangerous; any slightly crooked stride from the horse would have driven the spike into its opposite leg and cause severe damage. So I’m going to go with the ‘booties tied around the fetlock’ design for Roman horseshoes.

  5. Blake, this was extremely interesting and informative! I recognize most of the conditions you mentioned from books I have read, but there was rarely enough context to grasp exactly what the problem was, how it was caused, or how to deal with it. Thanks again for continuing this series!

  6. “Don’t look a gift horse in the mouth,” has to do with seeing the horse’s age by the teeth, right? As in, be grateful that someone gave you a horse, even if it is older than Methuselah.

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