Farriers should not be trying to straighten limbs in aged horses. You’re simply trying to make the horse comfortable for it’s conformation. To help a horse become comfortable, you need to limit hoof distortion by trimming the hoof to bear weight as evenly as possible. A farrier’s key to hoof balance is being able to recognize the cause and effect of distortion. If uneven growth is allowed to continue unchecked, the hoof capsule distortion could cause a breakdown of hoof integrity and eventually lameness in the limb. Uneven hoof growth due to conformation problems will compound those problems.When farriers are dealing with a client whose horse has a balance problem, references that the farrier may cite may not be up-to-date. This problem may also occur when working with veterinarians. The farrier needs to be up-to-date on the current research and theories to be able to explain why the problem exists in the first place.As farriers, we are working from the coronary band down. What happens above the coronary band can be seen in the distortion of the hoof capsule. My philosophy is if you can balance the hoof according to weight bearing, the horse will land and move the best it can for its conformation. I recommend using Russell’s “center of gravity” as a point of reference for solving hoof distortion problems. More precisely, using the center of the frog because the frog never really moves, the hoof capsule distorts around it.A major influence on hoof angle is tendon tension. The amount of tension will change how the hoof loads. If you have an upright foot, chances are the deep flexor tendon will be tight which will limit the amount of load on the heels by transferring weight bearing to the toe, limiting toe and increasing heel growth. If you have a horse with a low hoof angle and under run heels, there will be less tension on the deep flexor tendon, increasing weight, limiting growth and crushing the heels.For the hoof capsule to function normally, it is important to make sure that the hoof is trimmed to its proper proportions and kept symmetrical both medial/lateral and anterior/posterior. When you are limited with what you can accomplish with trimming, the fit of the shoe can complete the equation by providing a base of support or platform for the limb above it.
Anterior/Posterior: The hoof capsule interprets weight bearing and load in two ways. It either loads forward of the centerline or back of the centerline and tendon and suspensory tension allows the fetlock to drop what we consider normally, excessively, or very little. All of the above effect growth of the heels and toe. The least amount of growth will occur where the majority of the weight is applied. The hoof will grow at a faster rate where the least amount of weight is applied, causing an imbalance which is compounded over time. When you add torque at breakover it becomes more obvious why long toe low heel syndrome is as detrimental to soundness as it is.
Medial/Lateral: The hoof capsule also interprets weight bearing and load in two ways. It will be either base-wide, loading outside the centerline or base-narrow, loading inside the centerline. The effects of base loading are seen from the widest part of the hoof back in the heel quarters. The quarter bearing the most weight will have the least amount of growth, become more vertical, closer to the frog and in extreme cases, considered a sheared heel. The quarter bearing the least amount of weight will grow at a faster rate away from the center of the hoof, causing an imbalance compounded over time. Base-wide will effect the medial heel quarter. Base-narrow will effect the lateral heel quarter.
The second consideration is toe-in, toe-out conformation. This effects the hoof from the widest part of the foot forward or the toe quarters. The quarter bearing the most weight at breakover will have limited growth while the opposite toe quarter will grow at a normal or a faster rate becoming a flair. Toe-in will have a flair on the medial toe quarter. Toe-out will have a flair on the lateral toe quarter.
All distortion in the hoof capsule is a combination of weight bearing, compression, load and torque and is directly related to the conformation of the limb above it. Remember, whenever horses are standing on their feet these forces are at work effecting growth.
Once we have an understanding of why hoof capsules distort, only then can we actually start to “balance” horses.