Conformation refers to the physical appearance and outline of a horse, and is dictated primarily by bone and muscle structures. Although every discipline, every breed and every genetic line has deviations, it’s a sensitive subject for many equine caregivers. I’ve found that it doesn’t matter how receptive the caregiver is to what you are trying to do and help the horse — somehow it still inflicts pain in their brain when you say something “negative” about their animal. For this reason, it is important to handle the subject with care. 

Our objective as farriers addressing conformation is to allow that animal to perform to the best of its ability with what it has, and enhance it. The way that we do this is through our attention to detail. Early on I made the mistake of thinking that my job was from the hairline down and I was humbled many times and taught that wasn’t quite so. Every detail is important; everything around you and every part of that equine’s life is important to your ability to help them. Fine-tuning your observational skills and understanding the types of conformational deviations you are likely to encounter and their origins will better position you to provide the best hoof care solution for the horses in your care.

Look at All the Angles

The best way to assess a horse’s conformation is to view it from a variety of perspectives. Looking at a horse in cross-ties will only provide you one angle. At a minimum, watch the horse walk out of the stall toward you. If this is all you do, it’s a positive first step — but you are still missing a lot of information. You will be better served to collect a variety of views of the horse. 

I had the opportunity to observe how International Horseshoeing Hall of Fame member Seamus Brady evaluated a horse — he went to its events and he watched it warm up — he saw what it was doing in different environments and at different times. This level of observation is invaluable to a farrier. There are certain visual clues a horse can provide that will help us define what’s going on internally and how to address it through proper hoof care. Observe the horse from the front as well as the hind. Your perspective will change with the direction from which it is viewed — and change is constant. Look down the horse’s limb and identify the locations of twists and bends; try to envision where the pinching points are so you can help change the stresses to that limb. Ask another person to view the horse — perhaps an apprentice to verify what you are seeing and provide additional insight. 

Besides this basic visual assessment, accumulate additional information to aid in helping the horse — look at radiographs, MRI’s, cat scans — then put it together. Long before you begin working on the hoof, start forming a vision of what you want to do to help that horse; to change its balance or its posture — yes, you can change its posture. Understand that what you do today may not be what you do in 4 weeks when you work on the horse again. There will be new changes reflected from what the horse has been doing, its nutrition, its environment and your previous shoeing job. Everything that you do to that foot on this visit will have an influence on the entire body of that animal that you can see in future visits.

Physically examining the horse is another way to gather important information about a horse’s conformation. You can do this by extending the limbs in the natural range of motion. Some horses may extend a foot just in front of the opposite limb; while others may have a greater or different range of motion. The deviations within the limb will create pinch points and if you put more pinch on it you are going to get a negative response. Flex the limbs and feel the joints. If you’ve been working on a horse consistently and you find one day you go to lift up the hind limb and the horse is less responsive to what you’re doing, it’s important to let someone know about the change in behavior. Otherwise pretty soon you’ll be shoeing it down on the toe of your steel-toed shoe because the horse can’t lift it up anymore.

LEARN MORE

Sign up for the International Hoof-Care Summit Virtual Clinic Series to access a recording of Mike Wildenstein’s Burney Chapman Memorial Lecture presentation “Defining Equine Limb Conformation” from the 2018 IHCS by visiting AmericanFarriers.com/0721

If you want to validate what you’re doing and what your perceptions are — watch the horse and its reaction. That’s going to tell you a lot about what the horse is feeling. You may find some horses are quite uncomfortable before you start, and just the opposite after you finish. When you set that foot down, watch for licking and chewing. When they lift up the contralateral limb to put weight on the one you’ve just worked on — that’s a good sign. If not, you may have a problem. Look to the horse to determine if you are on the right path, because the horse is going to tell you. It’s not just that its performance is improving; maybe the horse’s attitude changes, or its stance changes — all of those things are important validations of your work.

The next step is to evaluate the hoof conformation for form and function. This is something we can keenly understand because hoof care professionals, like the horses we work on, have certain stresses to our body and pathologies resulting from repetitive behavior. It stands to reason if you are working with a hoof between your legs all the time, that you are going to wear the outside and the heels of your shoes. One heel may wear more than another, depending on the conformational deviations within your limb. 

When I first started out, I didn’t care about my own shoes — I just hoped my first client paid in cash so I could buy gas to get to the next. But as my shoes wore out, my gait changed. All of a sudden I’m traveling more base narrow, close together. I’m starting to feel pain. I am having compression of the joints on the inside of my limb and elongation of the soft tissues on the outside where those deviations are. If I had just gotten myself new shoes, I could have prevented a lot of issues.

The horse is the same way. Look at the hoof. How is it wearing? Where is it wearing? Which way is the hoof capsule moving? The answers to those questions all provide information that you can use. 

The hoof capsule is all soft tissue and it’s very flexible. It may be more flexible in the Midwest or in the Northeast than it might be in Arizona due to the climate, but it is flexible. It’s part of the horse’s natural capacity to absorb concussion and stress. It will flex and move depending on the stresses applied upon it. As you evaluate the hoof capsule look for symmetry (or asymmetry), collapsed heels and flared toe quarters, as they’re all so important to your shoeing strategy. Remember: every limb has deviations and no two limbs have the same deviations. In fact, the amount of deviation can vary significantly between two limbs on the same horse, so it’s important to evaluate each hoof and limb individually. 

A rotational deviation is a twist in the limb, whether it’s toed in or toed out (Figures 1a and 1b). To determine where the rotational deviation begins and ends, start by looking at the limb from the top. Follow down to the tarsus, carefully observe the surface area of the tarsus and continue downward looking at the tendons and ligaments. Figure 3 is a horse with abaxial rotation in the stifle and axial rotation down low. If you follow that to the tarsus and then observe what happens in the fetlock, you’ll see the hoof is actually going a little straighter forward. Using the direction of the frog can help inform the shoeing strategy you develop (Figure 4).

Rotational Deviation

There are several deviations that we can look for when assessing a horse’s conformation: rotational, flexural and angular. A rotational deviation is a twist in the limb, whether it’s toed in or toed out (Figure 1a and 1b), and those twists can be multiple throughout the limb. You can have them going out at the top and in at the bottom with maybe a few different turns in between — and all of those turns are very important. Where they are located determines the influence on the horse. Rotational deviations can be in a long bone or they can be in a joint. If they’re in a hinged joint, like the fetlock or the stifle, they’re going to create a lot more twisting of the limb as the animal moves than those that may be in a long bone. It’s important to note none of the joints or the bones are completely equal from one side to another, or from front to back. 

Evaluate the limb from above to determine where the rotational deviation starts and ends. In Figure 2, follow down to the tarsus, carefully observe the surface area of the tarsus and continue downward looking at the tendons and ligaments. We’ll often look at the tarsus and decide whether its tarsal varus or tarsal valgus, but that’s not enough information. Look at the fetlock: where does it go? And the bulbs of the heels — they tell you a lot about the stresses that are being applied to the horse. Gravity falls in straight lines — you have horizontal and vertical stresses. Horses with rotational deviations are going to have a lot of diagonal stress on the lower limb.

We’ve bred horses for thousands of years to have an abaxial rotational deviation in the stifle joint because we want the hocks located underneath the body as the horse is propelling itself forward. If the hocks are closer together and stay under the body, the horse has more propulsion. Current research shows us that horses that toe out have less incidents of lameness issues — but that may vary depending on discipline, environment, or terrain. 

Figure 3 is a horse with abaxial rotation in the stifle and axial rotation down low; follow that to the tarsus and then observe what happens in the fetlock; the hoof is actually going a little straighter forward. As that horse moves, it twists. Old textbooks advise that you should put a bigger calk on the shoes of these horses. If you do that, you’re creating a stress to that stifle joint and possibly the fetlock joint. Having worked in clinical situations for more than 40 years and watching these animals come in and leave, I have seen that if we put a calk on them, we have stifle issues. Your collateral ligaments are going to be torn and injured. This is a human-created problem resulting from putting too much traction on the horse for the surfaces they compete on — surfaces we have been changing.

Top competitors are performing on stickier surfaces than ever before. As a result, we’re having more soft tissues problems because regardless of what you put on that animal, it’s not going to be able to twist as it naturally would on these surfaces. 

The whole hoof capsule is soft tissue and can rotate 15-18 degrees. If we change the stresses on that foot with trimming and shoe modifications, we can “derotate” it, both on the condylar joint and as a hoof capsule. If you pull a limb forward and it toes out (abaxial rotation) when you put it on your hoof stand, and then you fold it and flex it underneath the animal and it looks like it’s toeing in — with the frog pointing toward the midline — that’s a rotational deviation within the fetlock. If the limb is fairly straight forward when it’s in its stance phase, that’s important information, too. Use the direction of the frog (Figure 4) to help inform the shoeing strategy you develop. If there’s a rotational deviation or several rotational deviations within a limb, that hoof is not going to breakover at the point of the frog. If we’re going to help that horse, it’s important that we put rollover motion in our shoe or in our trim at the point at which that horse breaks over, not where we want it to. We’re not going to change how that horse is put together, but we can help it perform to the best of its ability with what it has — and possibly last longer.

A lot of what we do is preventative. If we start out with a foal that has deviations we might try to help them go straight. If they grow up and continue to have deviations, then we need to prevent some of the issues or the stresses that can create problems in these animals by making modifications to their shoes. You can use your SX7s or SX8s on them, but modify the shoes according to the foot and limb stresses to help them out. It doesn’t take much: a slight crease, or a slight bevel can make such a dramatic difference in those horses. If you’re working on elite horses, a slight difference in width of web from one side to another can make an incredible difference in how those horses go and perform.

These are several examples of flexural deviations including, from left, a broken forward or a broken back hoof pastern axis (Figure 5), back at the knee (Figure 6), over at the knee (Figure 7), sickle hocks (Figure 8).

Flexural Deviations

Another common deviation is flexural. Flexural deviations often manifest as a bend, clubfoot or loose ligaments and tendons. They can be acquired in a variety of ways, including nutritional problems, injury, and general horse care mismanagement. A broken forward or a broken back hoof pastern axis as in Figure 5 is a flexural deviation. These all create stress and as farriers it’s our job to determine the best way to alleviate that stress. Observe the hairline from the side on Figure 5 and look where that goes. If that line is pointing towards the belly, you need to get the veterinarian involved because we have an issue here. There’s probably a broken back axis that needs some radiographs and some more information to help you out. 

Figure 6 is an example of back at the knee, another a flexural deviation. In this situation, the front of the knee is pinched while the soft tissues on the back are elongated. The popped knee that is visible in Figure 6 is a result of this conformation. The Standardbred horse pictured was a racehorse that was not competing very well anymore and it came into the clinic for an evaluation. The trainer thought there might be something wrong with the horse’s breathing but all I could see was that knee — the wind resistance alone would slow the horse down!

They put it on the treadmill and the horse did have a breathing problem. At this point, the veterinarian was tired of listening to me grumble so they did a lameness examination. By gosh, that horse didn’t feel a thing about that knee; it didn’t block out, there was no lameness situation. I was humbled. It was a good reminder to listen to everybody. 

Figure 7 is over at the knee. This condition is more often acquired. Figure 8 is an example of sickle hocks. In some breeds, like your reining horses, we want that because it will allow a horse to get down and slide, which is a good thing — to a point. Then it can be excessive. Conventional wisdom tells us that if a horse has a soft tissue lesion in the back part of the foot or the limb, we should increase the width of web of the shoe in that area. But if we hang a lot out the back door and wedge the heels of that horse — it only becomes more sickle hocked. Essentially, you’ve elongated the tissue on the back of that limb; you didn’t shorten it. You’ve also put more compression on the front of the hock joint. A straighter horse, like the one in Figure 9, would be a better candidate for such a treatment modality. This horse has a broken back hoof pastern axis, too, even after trimming. And then you could put a wedge on that or a bar shoe or something like that and help this horse out. So, paying attention to that flexural deviation, or the multiple flexural deviations will make a big difference on the outcome of whatever you do for that horse.

Conventional wisdom tells us that if a horse has a soft tissue lesion in the back part of the foot or the limb, we should increase the width of web of the shoe in that area. A straighter horse, like the one in Figure 9, would be a candidate for such a treatment modality but it would only worsen the situation for a sickle hocked horse.

The hairline can indicate what is happening above the hoof. The first limb, which has the coffin joint valgus, you’ll notice the hairline is pushed up in the lateral toe quarter. In the second limb, the one that has more varus than it has valgus, the hairline is pushed up in the medial toe quarter (10). When the coffin joint or maybe even the pastern joint is valgus, the foot will flare strong to the outside because of that lower limb deviation, even though the horse may be base narrow, traveling close together (11). Angular deviations can help you determine how to work on a horse. For a horse that is carpal valgus, fetlock varus, coffin joint valgus you might want to work on it a little closer into the midline.

Angular Deviation

Angular deviations are any bend in the limb. Those of the lower limb are often neglected and it does take a lot of practice to see them. There are two common types of lower limb angular deviations — varus and valgus. Whether the limb is varus — going inward toward the centerline — or valgus — going out— will result in significant differences in the hoof shape. It is important to note that just because a horse has deviations does not mean it won’t perform. 

The horse in Figure 10 has multiple deviations within the limb. If you look at the first limb (far right) you see you have a fetlock varus. Then at the coffin joint it goes out again. This foot is going to flare laterally because of that lower limb deviation. Now look at the second limb from the right in Figure 10. Here we see a slight fetlock varus, and then it is straighter. This foot is going to flare towards the medial toe quarter. If we put exactly the same shoe with the same modifications on these two limbs, we’ve done that horse a disservice. This is why we need to pay attention to these small details. You can look at the hairline to help you out.

If you look again at the first limb in Figure 10, which has the coffin joint valgus, you’ll notice the hairline is pushed up in the lateral toe quarter. In the second limb, the one that has more varus than it has valgus, the hairline is pushed up in the medial toe quarter. The hairline, in this way, gives you an indication of what’s going on up above. That hairline is pushed up because of vertical force, which needs to be compensated for in whatever you do down below. The third and fourth limb have multiple deviations all down through the limb. The third limb is carpal valgus and the fourth is carpal varus, plus bench. All of those deviations are influencing how that horse is going and the stresses throughout the limb.

Figure 11 is an unfair picture because we have a farrier holding up the other limb, but it really illustrates what happens when the coffin joint or maybe even pastern joint is valgus. The foot will flare strong to the outside because of that lower limb deviation, even though the horse may be base narrow, traveling close together. This is very important information to help you help the horse. We have guidelines that say you need to put an increased width of web on a on the outside branch of a horse that is base narrow, but if you put an increased width of web on the one in Figure 11, you’ll create a greater flare. 

The horse in Figure 12, is carpal valgus, fetlock varus, coffin joint valgus but the varus is greater than the valgus. This horse is probably pretty sensitive if you grab that foot and pull it out from your body because you’re pinching that knee joint more on the outside it’s going to give a negative response and give you a pull. This limb, because it’s carpal valgus, you might want to work on it a little closer into the midline. 

Look for signs of stress and their origins. Hoof shape shows clues to signs of stress, disparity in the bulb (13) of the heels indicates a horse is landing harder on the outside, a proximal shunt to the heel is due to vertical stress (14) and diagonal and horizontal stress create flares (15). Wear is also an indicator of stress. My plow horse wears its toes off (16). This has everything to do with the horse’s job, which consists of walking 3 to 4 mph in a straight line pulling a 12-inch (furrow) plow.

The Effects of Stress

Hoof shape is indicative of stress. Disparity in the bulb of the heels, like we see in Figure 13, is one clue. If you have a base narrow horse, it’s normal for the lateral branch to be a little bit larger unless that lateral heel has an axial rotation. If the horse is landing slightly harder on the outside, that’ll crush that heel. So, if you have a windswept horse, you’ll notice disparity in the bulbs of the heels of that horse. 

A proximal shunt to the heel (Figure 14) is due to vertical stress. In heavier horses this will have a greater influence. The horse in Figure 14 probably has an axial rotation, is base narrow, has more varus than it has valgus, lands laterally, loads medially and breaks over the lateral toe quarter. This hoof capsule will rotate, the inside pushes up, the outside drags forward, and it can rotate on the joint, and as a hoof capsule, that laminae will stretch depending on the stresses applied on it. If you don’t adjust for this, it will fracture right at the end of the coffin bone; that’s where those splits always happen as you have a shunting force, that vertical stress, on that heel. Detecting stress isn’t always straightforward. My perception as a casual observer watching the horse on the floor may be different than the radiograph, which shows that joint is compressed. It may be different than what the T square shows you because that is to address straight lines, and I’ve never seen a limb with a straight line. 

Diagonal and horizontal stress create flares (Figure 15). Look at the rings on the hoof in Figure 15. The stress lines in that hoof show you compression and elongation, as well as where there’s been a difference in hoof movement as that hoof was growing. It takes 9 months to a year for that hoof to totally replace itself so it provides a map or a reference to the horse’s history during that time frame. Deviations in hoof growth will tell you about the stresses that horse has been experiencing. The hoof wall flexes and deforms according to stresses and those deformations are shown in a variety of ways: flares, cracks, splits, deviations in hoof growth, hemorrhaging at the hairline, the hairline sticking out, the hair sticking up. All of those things are indications that something is going on. 

Another indicator of hoof stress is the wear on the bottom of the shoe. Look at that every visit with the horse and very closely because changes in hoof wear indicate a change in how the horse is going, and a change in the stresses that are applied upon that hoof. To provide the best care for that horse you need to make yourself aware of those changes. There are differences in wear according to what the horse does. 

My plow horse wears its toes off (Figure 16). This has everything to do with the horse’s job, which consists of walking 3 to 4 mph in a straight line pulling a 12-inch (furrow) plow. It’s only expending as much energy as it has to pull that plow. The average that a good horse and person can plow is about an acre a day and you will travel 18 miles to get that acre plowed walking. The horses are not going to overexert themselves in the morning because they want to make it through until to the end of the day. So that horse is wearing the toe. That doesn’t mean we’re going to trim them that way, but that’s the way they wear. 

A Thoroughbred or racehorse is going to show different wear because it’s extending way out there — elongating its stride. It’s going to have different stresses on the hoof than the horse that is working at a walk. 

If you want to make a difference in the horses on your books, your shoeing schedule has to be brought back to 4 weeks. When I grew up, we had our heavy horses shod four times a year as the traction devices needed to be changed for the seasons and a good farrier could keep them on for 4 months. But times are changing. 

It’s amazing what you can do on a 4-week schedule — how much you’ll find that you can trim off if we just leave a little. We start losing a couple of degrees each week after the fourth, and it’s hard to catch up. I know it’s a hard concept to swallow, but it’s amazing the differences it can make.

If you want to help horses, your observation skills are going to be critical. But it’s more than just watching the horse walk — although that is very important. We have to going beyond our basic observation and more in-depth. 

Trust your feelings, your intuition — we don’t use that enough. We have our book learning, which is fantastic, but it’s that “feel” that you get from cognitive learning. You just know that this horse has something going on. Your brain and your body are working together to define that in the past of the thousands of horses you’ve worked on, the horses that felt like this did better with this type of shoe or this type of modality. That feel is so important and something we incorporate in our everyday work. If you don’t listen to that intuition, you’re doing yourself and the horse a disservice. When I go for a surgery I want a surgeon that has great book learning but also one that goes by feel. 

But we can always learn. Keep at it and it’s amazing what this occupation can do for you. Set the stride and keep the pace to greater understanding. Conformation will always challenge us. As we increase our learning and our understanding, we can better serve the horse and the industry.