Common Hoof Problems and What to Do About Them by EponaMind

Originally appeared in Trail Blazer magazine 2009

Common Hoof Problems and What to Do about Them Monique Craig The Epona Institute

Figure 1: A hoof with good conformation. The radiograph in 1B shows a well-formed ‘arch’ which supports the pedal bone in a good internal stance.

In the ideal situation, our horses come with perfect conformation and great hooves. A good hoof should be well set under the ‘bony column’, have good horn quality, support length, good sole depth and arch definition (see figure 1.) In reality, most of us have horses with some conformational flaws and with less than perfect hooves. Before I dive into the most common hoof problems, I want to stress the importance of implementing a proper hoof care routine. Most common hoof problems can be helped, and sometimes completely avoided, if some simple steps are followed. For instance, keep your horse’s weight within a reasonable range. Make sure that your hoof trimmer or farrier has enough knowledge about your horse’s situation, problems, and usage in order to do the best for your horse.

Originally appeared in Trail Blazer magazine 2009

Have your horse trimmed or shod on a regular basis -- a six week interval is generally fine for horses that don’t have hoof issues. However this schedule should be adjusted to fit specific needs. Try to give your horse as much free exercise as possible to help in maintaining hoof quality and health. Pastures and large turn-out areas with room to roam are often the best. Whenever possible, manage your usage of pastures and turn-out areas based on weather conditions -- sustained muddy conditions may cause hoof problems. If your horse is stabled in a boarding facility with no available turn-outs, try to find a way to safely free exercise your horse -- an enclosed arena or a large round pen may do the trick. Try to ride your horse thoughtfully: hoof problems can be generated by poor riding habits and/or bad riding equipment. Horses are masters at gait compensation, and this is normal, but favoring a leg over the long term may lead to hoof issues and eventually lameness issues. Try to keep records of your horse’s hooves while they are at their best. Document the shape of your horse’s hooves by taking photographs, and ask your veterinarian to take yearly preventative radiographs. This way, if something starts to go wrong, you (and your farrier and/or vet) can look at the photos and radiographs of your horse’s hooves were when things were good. Ideally, you should have a series of lateral and frontal radiographs taken on all four hooves, but if money is an issue, ask only for lateral radiographs of the front hooves. An ounce of prevention is worth a pound of cure!

Why do Hooves Show Signs of Problems? Loading and shearing forces placed upon the hoof will invariably distort the hoof to some extent. A healthy hoof is well designed to withstand such forces. If proper hoof management is implemented, a good hoof will maintain near optimal functional shape for a long time. Unfortunately, poor genetics along with inadequate foot care may turn some flaws into serious hoof problems. The hoof capsule – the hard keratinized part of the hoof – provides protection to the soft tissue but also plays a very important part in supporting the load (much of it via the sole) and dissipating energy (much of it via the walls.) The whole hoof capsule works as an entire system. Natural and/or man-made deformities in any part of the capsule will affect the overall function of the hoof. The soft tissues can be displaced as a result of capsular deformities and so internal issues may be related to the external shape and loading of the hoof. Through correct trimming (see figure 1) along with appropriate prosthetics (aka ‘shoes’), it is possible to maintain even problematic hooves in good health. Copyright 2009 by The Epona Institute

Originally appeared in Trail Blazer magazine 2009

While it is impossible to cover all conditions in detail, I will attempt to highlight common hoof problems. My main goal is to train the readers’ eyes to recognize capsular deformities. For the sake of simplicity, I will address these problems in a segmented manner. In reality many of these problems may be related and so it is difficult – and somewhat irresponsible – to come up with a specific solution for each problem. I will restrict myself to presenting general guidelines that may help alleviate some of these issues. ‘High Low’ Hoof Syndrome Generally, the ‘high low syndrome’ refers to the shape and height differences between two front hooves, but the problem can also occur in hind feet. If we exclude poor trimming techniques, a true ‘high low syndrome’ describes hooves that have very different shapes. One hoof has the tendency to be more upright and to grow more heels than toe. The other hoof is flatter looking with low heels and has a tendency to grow more toe than heels (figure 2.)

Figure 2: The left hoof (A) is more upright hoof and tends to grow heels faster than toe. The right foot (B) which is lower, thinner soled, somewhat splayed, and grows toe faster than heel.

Originally appeared in Trail Blazer magazine 2009

Figure 3: Same horse as figure 2. The higher foot has greater sole thickness (A) and the lower foot has a thinner sole (B). By the use of packing and glue-on shoes, the lower foot can be given the same effective thickness of protection (C) as the higher foot. In essence, the two hooves have inherently different morphologies. The low hoof may tend to have weaker bars, a flat sole and a flatter pedal bone while the high hoof would tend to have stronger bars, more curvature to the sole and a more upright and ‘cupped’ pedal bone. In the case of the high hoof, I am not talking about a more serious condition known as “club foot”. The Copyright 2009 by The Epona Institute

Originally appeared in Trail Blazer magazine 2009

way to stabilize such problems is to trim these hooves more often. This is one way to diminish the heel unevenness between the two hooves. The high hoof should have adequate amount of heels removed. Note that for both hooves, the heels should be backed to provide support to the bulbs. There will be more heels to remove for the high hoof and less for the low hoof. Generally, I am conservative with removing sole. The sole provides support to the entire limb; therefore it is not very wise to be aggressive with trimming soles. This is especially true for a weak soled hoof. In extreme cases, I use glued-on shoes and rebuild the low hoof with extra glue (as in the radiograph of figure 3C.)

Figure 4: Sheared heels are generally noted from the rear as in (A.) Notice the difference in height between the heels and the deformed shape of the coronary band. In (B) we are looking from the rear at a sole with the pedal bone placed on top. The blue line shows that, for this hoof, the axis of the coffin-joint is not parallel to ground, as it probably should be.

Originally appeared in Trail Blazer magazine 2009

Sheared heels Although some people dispute it, hooves are inherently asymmetric, and there is no reason to try to ‘correct’ asymmetries that are natural. The medial (inside) hoof wall is generally more upright than the lateral (outside) hoof wall. Pedal bones are slightly wider to the lateral side than to the medial side. The hoof has a natural tendency to grow slightly tilted to the lateral side. These natural asymmetries and asymmetric growth patterns make it tricky to trim for proper medial-lateral balance, and errors in trimming can be the start of the ‘sheared heel’ problem. Excluding serious hoof pathologies, most sheared heels are probably the result of trimming issues (figure 4.) This problem often starts with a medial to lateral imbalance and is often compounded by metal shoes fit too tight to the hoof or fit too wide at the toe compared to the heels. It may take some time to restore a hoof with seriously sheared heels since this problem generally will have also affected soft tissues. Try to catch this problem before it degenerates into a real issue.

Figure 5: Contracted heels shown from the inside and the outside. On the left (A) we have a normal hoof, and on the right (B) a hoof with contracted heels. The upper portion shows a view of the sole dermis, bar papillae and frog dermis that connects to the inner portion of the entire keratinized sole. The lower portion shows a view of the outer portion of the keratinized sole that we normally see.

Originally appeared in Trail Blazer magazine 2009

Contracted heels Contracted heels are generally defined by the â&#x20AC;&#x2DC;shrunk lookâ&#x20AC;&#x2122; of the back of the hoof (figure 5B.) In the case of contracted heels, the heels and bulbs are spatially close to each other, and the frog has lost some of its width. Some hooves have a natural tendency to contract in the summer, especially upright walled hooves. This is in general not a big issue. These hooves need to be trimmed more often by lowering the heels and by allowing the frog sulcus to stay open. This is achieved by removing excess dried out frog in the caudal part of the frog. The frog sulcus is the little dip in the back area of the frog (figure 5). Some hooves have not only contracted heels but a completely contracted hoof capsule. In extreme cases, the circumference of the coronary band (junction between the hoof capsule and hairline) is wider than the circumference of the sole. In cases such as these it is crucial to allow the hoof to expand naturally over some time. Contracted capsules may be the result of metal shoes fit too small to the hoof. Over time, this situation can be helped (figure 6.) To make matters worse, you can have a combination of contracted heels and sheared heels!

Figure 6: Before (A) and after several months of corrective trimming and shoeing (B). Note the difference in the shape of the capsule and the frog. Note the frog sulcus in figure 6B.

Originally appeared in Trail Blazer magazine 2009

Dropped sole A dropped sole is a sole that has been crushed and pushed down past the walls. Most mature horses have some areas of their sole that are slightly crushed. Blame this on gravity! As usual, there are many ways in which a sole can be crushed. When soles drop seriously it is a sign of mechanical damage at the sole, wall, and soft tissue. In serious cases, the pedal bone is actually pushing down to a point that it sinks quite far into the sole (fig. 7.)

Figure 7: The top images (A) show a pedal bone that has sunk or crushed down into the sole. In contrast, note how in the lower images (B) you can see the edge of the pedal bone as it rides fairly high on the sole. Images: courtesy of Mike Savoldi. Radiographs are good means to assess sole thickness and give valuable information about the shape and stance of the pedal bone inside the hoof capsule. A horse with a dropped sole may display a poor arch definition, and sometimes a large distance between the extensor process and the coronary band (figure 8.) Providing sole support is helpful. Applying sole support to a dropped sole must be done carefully. A dropped sole may cause the sole dermis to be tender, hence abnormally sensitive. The sole dermis is the soft tissue between the keratinized sole and the pedal bone. If the proper support material is applied correctly this should not be an issue. Have your farrier â&#x20AC;&#x2DC;hoof testâ&#x20AC;&#x2122; the sole prior to packing --- this will help greatly in locating the sore spot on the sole. It is easier then to decide which support material to use, and where to place it.

Originally appeared in Trail Blazer magazine 2009

Figure 8: In image (A) the horse is standing on its sole, which has dropped down below the length of the hoof walls. In (B) a radiograph is used to assess the sole thickness, and a parameter called “P3 Descent” which measures how far down the pedal bone is relative to the coronary band.

Wall Detachment and White Line Disease The white line is the yellowish-white region between the sole and the walls (figure 9). This region binds the sole to the walls. Note that the phrase ‘white line’ is sometimes erroneously used in reference to the white pigmentation of the inner walls. Damage occurs to the keratinized walls and the sensitive laminae when the attachment (a.k.a. the white line) between the sole and the walls becomes compromised. Some of the reasons why the white line junction fails may be factors such as thin sole, poor load distribution, and excessive stress at toe either due to excessively high heels or excessively long toe. Mechanical failure of the white line causes varying degrees of wall separation and possibly lamellar damage. Once this process occurs it makes the hoof capsule more sensitive to ‘white line disease’ which is caused by a fungal infection. There are varying degrees of white line disease. This disease often occurs at the toe, so sometimes the term ‘seedy toe’ is used to describe the problem. It is important not to confuse simple wall detachment with white line disease. A seasoned farrier or veterinarian will be able to notice the difference but to be absolutely sure, you must send a sample of the affected horn to be tested in a lab. Often in the case of white line disease the entire affected area will need to be debrided and treated, but such radical measures are not necessary with a simple case of wall detachment.

Originally appeared in Trail Blazer magazine 2009

Figure 9: The white line circled in blue binds the walls to the sole, shown in close-up in figure (A) and in a larger scale in figure (B). The white line is visible all the way around the sole from underneath (C). Images: courtesy of Mike Savoldi. A high-quality radiograph can be used to see how far up the hoof wall the infection has gone (figure 10.) There are products on the market that are very efficient at killing bacteria and fungi. However if the underlying mechanical cause of the problem is not addressed it is very likely that this problem will re-occur.

Originally appeared in Trail Blazer magazine 2009

Figure 10: A radiograph can be used to see how far up the hoof wall the problem has gone. Note the exceedingly long toe of this hoof. Quarter Cracks The areas of the hoof capsule known as the “quarters” bulge out during the loading cycle as the horse moves. Anatomically, the quarters represent the widest part of the hoof (figure 11), therefore this area needs to be able to flex adequately.

Figure 11: The red boxed area is the most likely region for quarter cracks to occur. The blue arrow represents the load, due to the horse’s weight, coming down the bony column.

Originally appeared in Trail Blazer magazine 2009

One approach to remedy a quarter crack is to dremel into the wall. I personally don’t recommend this --- if anything, it will weaken the entire capsule further. By design, the hoof capsule is meant to fight cracks *. I generally bevel the damaged quarter at the junction of the sole and wall to relieve mechanical stress in this area. I then use either a combination of glue or patching material to strengthen the damaged wall area. Supporting the entire sole may also be helpful in stabilizing the internal displacement of the pedal bone over the sole.

Figure 12: A quarter crack that has been patched. Conclusion At the risk of over-simplifying, I believe “the trim is everything”. I am also a believer in using packing to support the bars and caudal (rear) portion of the foot, and I prefer to use prosthetics that allow the hoof to flex and move as intended. With these principles in use, the problems discussed in this article will occur less frequently. Beyond these basic ideas, each situation must be handled in a way that is best for the hoof in question.

If you want to know more about the design of the hoof capsule, please consult the article I wrote for this magazine in 2007 entitled: ‘The Hoof Capsule: Wood or Skin’. *