HOOF DEFORMITY.
Here are some examples of the way hooves commonly deform. I hope this page will be helpful to you in identifying the hoof problems your horse may be suffering from. If you suspect your horse has some of these issues talk to a specialist trimmer, and remember all horses' hooves will improve with regular natural trims. Even healthy hard working hooves are seldom perfect and often exhibit some small degree of deformity (have a look at the photo gallery for examples). If a barefoot horse has a conformational fault further up the leg he will often be able to compensate for it in his feet- growing hooves that at first glance look unbalanced. However, in some cases this ability to adapt is necessary to maintain soundness.
NATURAL HOOF TYPES.
There seems to be 2 basic types of hoof that if neglected when unshod deform in 2 different ways. I think of them as the tall foot and the splay foot.
THE TALL FOOT. Appears to have a strong laminar bond so that as the hoof wall grows longer it continues to grow straight and the hoof becomes taller. The problem with this is that the frog is lifted off the ground and out of function, and the hoof tends to contract and become narrower.
Above is the hoof of a 4 year old that has not been trimmed for some time (if ever). There is a small amount of flare at the toe but the wall is mostly straight. Notice how high the heels have become, they are much longer than the frog. The frog is not able to reach the ground and therefore does not receive the pressure and release stimulation it needs to be healthy. The positive with this hoof type is that regularly trimmed to prevent this excess wall length, the strong laminar connection gives strong, tough hooves.
Above is the same hoof after 8 months of natural hoof care. Note that the heels are now level with the frog.
THE SPLAY FOOT. Appears to have a weaker laminar connection. When neglected the hoof wall flares outwards, the white line stretches allowing the pedal bone into a lower position within the hoof, this pushes the sole and frog down. The positive with this type of hoof is doesn’t tend to contract but the sole will be flat and the frog can be subjected to too much pressure.
Above: Note the bell shape of the hoof caused by the flaring in the bottom two thirds. The sole view shows that the hoof is wide across the heels with a large frog, but sole and frog are flatterned.
Above: In the first trim it is possible to remove the worst of the flare, but only regular trims will allow the stretched white line to grow out and be replaced with well connected hoof wall.
Whether these differences are genetic or simply due to diet is not fully understood, however carbohydrate rich diets (too much grass) do seem to weaken the laminar attachment between pedal bone and hoof wall, allowing the wall to flare and the sole to flattern.
THE TALL FOOT SHOD. The healthy hoof is a cone shape, narrower at the top, wider at the bottom (see photo below left). As it grows longer it also gets wider. However, the shoe does not get wider, so as the foot gets longer it becomes narrower, contracting at the heels. This tends to happen in a hoof with good laminar connection (below right).
THE SPLAY FOOT SHOD. Placing a shoe on a hoof, forces the hoof wall to support all the horses’ weight. All the horses’ weight is suspended from the laminar connection, rather than the load being shared by the hoof wall, sole, frog, bars and heel bulbs as nature intended. A hoof with weaker laminar connection cannot withstand this much force and collapses into flare.
MEDIAL OR LATERAL TOE FLARE. Another way that unshod hooves tend to deform when not trimmed regularly is to develop medial (inside) toe flare. The point of breakover is generally on the lateral side (outside) of the toe, not dead central, so the medial side of the toe does not receive enough wear. This can be seen on the sole view of the right fore shown below. Note on the second photo that the lateral (outside) wall is growing down straight, and the medial (inside) wall is flaring because it is getting too long. This causes the leg to twist and the horse stands toe-in (pigeon toed). If the horse breaks over on the medial side of the toe the same thing will happen the other way round resulting in lateral toe flare and a toe out stance.
COLLAPSED HEELS - In the naturally well connected hoof the heels can collapse due to excessive growth between shoeings. A good farrier shoes the hoof with plenty of length at the heel of the shoe, but as the hoof grows longer, it also grows forward taking the shoe with it so the shoe no longer supports the heel.
Above: This 5 year old has excellent laminar connection, there is no wall flare even though the hoof is overgrown, but note the distance from the heel of the shoe to the vertical line dropped from the back of the heel bulbs. Compare this to the same hoof trimmed to an appropriate length. The heels have been brought back under the horse and are able to provide better support. If the horse suffers from this lack of support long term the heels will begin to drop towards the ground.
In a hoof with weaker walls the heels become crushed, the hoof wall is not strong enough to support the weight of the horse without help from the sole, frog and bars. With this type of hoof the owner will complain that their horse does not grow any heel, but in the photo the pink arrows mark the length of the heel, if this heel was strong enough to stand up it would be too long. The 2nd photo was taken after only 2 months without shoes. No longer forced to bear all the weight the heels have popped up.
BROKEN HOOF/PASTERN AXIS - Viewing the leg from the side, a line following the angle of the pastern should be parallel with the toe wall.
The hoof on the left has a parallel hoof/pastern axis. The hoof on the right has a broken back hoof/pastern axis. It is also possible to have a broken forward hoof/pastern axis, in which case the toe wall will be very steep giving the hoof a stumpy appearance. A word of warning here - the hoof on the left has a correct hoof/pastern axis because the pedal bone is tightly connected to the hoof wall. The hoof on the right has a broken back hoof/pastern axis because the laminae connection is stretched and there is a degree of pedal bone rotation. This damage must be grown out (supported by dietary changes) to achieve a correct hoof/pastern axis. Attempting to correct the hoof/pastern axis by over trimming the toe or heels can only do more harm.
MISMATCHED FEET - One foot is more upright or boxy. This can be caused by long term lameness; the horse favours the lame foot and puts more weight on the sound foot, causing it to flattern and splay. Or there may be a problem in the horses’ body which causes an alteration in gait, such as a shoulder injury. In this instance the boxy foot is a necessary compensatory change and should be respected.
The horse shown above had a long term abscess in the right fore, which became more upright, whilst the left had to support more weight and became wider and flatter.
FLAT SOLES - The sole should have concavity, like a shallow bowl. In healthy hooves the depth of concavity varies depending on the surface the horse lives and works on. When the laminar attachment between hoof wall and pedal bone is strong the pedal bone is suspended high inside the hoof capsule. This allows the sole to have concavity. When the laminar attachment is weak and stretched the pedal bone sags to a lower position in the hoof capsule. It then presses down on the sole causing it to flatten. A flat sole cannot have concavity cut into it with a hoof knife. In the barefoot horse the thickness of the sole is crucial for comfort, live or calloused sole is never removed in a natural trim.
BULGING OR CURVED HAIRLINE - When viewed from the side the hairline should slope towards the ground from toe to heel in a fairly straight line. It may bulge upwards at the quarters which can indicate the wall at the quarters is too long and pushing the hairline up.
HOOF WALL - The hoof wall should be growing straight and smooth. Flares, cracks, chips and rings indicate dietary and/or mechanical stresses.
Hoof Wall Rings - It is widely accepted that horizontal rings in the hoof wall occur when there is a nutritional change, such as winter grazing to summer grazing. Each ring marks an episode of metabolic or dietary stress. The hoof walls of a horse on an optimal diet are smooth and free from rings all year round. Hooves that are producing rings tend to be sore over stones. This is why diet is such a crucial element of riding barefoot.
Hoof Cracks - Develop due to improper hoof balance, neglect or incorrect hoof function.
FROG - Ideally this should be broad, the central cleft should look like a thumbprint or wide and open dip (below left). If the hoof in narrow or contracted across the heels, the central cleft can become a deep, narrow crack, which provides perfect conditions for fungus and bacteria (below right).
LAID OVER BARS - If the bars become overgrown they can grow forward over the sole. Whilst trimming of the bars should be kept to a minimum, in this situation the bars are trimmed back to allow normal growth.
Above left: With the shoe removed laid over bars and false (unexfoliated) sole are present. Above right: With the excess bar removed it can be seen that the bars have become bent by the pressure. Note also the corn on the medial heel (red, bruised area on the right heel of the righthand the photo), caused by the pressure of the shoe.
CORNS - This is a bruise in the seat of corn area (right heel of photo above right). It is caused by the pressure from the shoe. This can happen if the shoe is left on for too long - as the toe gets longer it pulls the shoe forward with it so that the heels of the shoe also move forward and press into the seat of corn. It can also happen if a shoe is applied that is too short at the heels, as is sometimes done if the horses tends to pull his front shoes off with the hind toe. The corn can progress from a bruise, and in the photos below there are black infected holes in the seat of corn. Corns heal easily when the shoe is removed.
WHITE LINE SEPARATION - If your horse is shod you will only be able to inspect the white line when the farrier re-shoes. It should appear narrow and tight. It may be stretched and wide, or be a depression which will fill with dirt. Either way it indicates dietary and/or mechanical stresses which have weakened the attachment between the dermal and epidermal laminae, causing the white line to stretch.
Above is a pre-maintenance trim photo of a pony which had been left untouched in a field for several years. Although he has had several trims the stretched white line shows that his feet have been severely flared and suffered from laminitis. A good natural trim can remove the worst of the flare, but only time and regular trims can grow out the underlying damage. Below is an example of white line separation causing a dip between the hoof wall and sole. In bad cases this separation can extend high up the inside of the hoof wall and provides a perfect environment for fungus and bacteria.
Note the much narrower white line on the hoof below. This indicates good attachment of the hoof wall to pedal bone.
HEEL LENGTH - Heel length varies from horse to horse depending the health of the hooves and is best assessed by a qualified trimmer. Ideally the heels should allow the frog to make light contact with the ground when viewed on a hard flat surface. On an uneven or yielding surface the frog will then receive the correct amount of pressure and release stimulation as the horse moves. This is essential for the development of the frog, digital cushion and lateral cartilages, the important shock absorbing structures in the back of the foot. Note on the photo below left of the shod hoof how the frog is unable to make contact with the ground and is therefore non-functional.
