Barefoot vs. Shod?
Wear versus growth is the first point to consider. The genetics and breed of the horse, the structure and conformation of the hoof, the surface on which a horse is worked and most important, for what purpose the horse is going to be used; these variables all influence the wear of the feet and will affect the decision as to whether the horse can be maintained barefoot. The structure of the foot is usually the determining factor as to whether the horse can remain barefoot. Maintaining the horse barefoot is best accomplished when or potentially when the hoof wall is thick and solid, there is good sole depth and there are soft tissue structures in the palmar / plantar section of the foot that are of sufficient mass. Breeding practices have had an influence on the structure of the feet, unfortunately not always for the better. Quarter horses have been bred for fashion while Thoroughbreds have been bred for speed; this often results in poor quality feet. More often than not (especially with Thoroughbred horses) the foot is not allowed to grow and mature into a so called "good" foot (Figure 1)1. Hoof development, particularly for the first three years is dependent on stimulation from regular exercise and turn out. Yearlings are often shod for the sales. The majority of horse's feet remain healthy until the time they are broke and enter training usually as 2 year olds. As training begins, the hoof capsule and its related structures are still immature, the animal is confined to a stall or small paddock, a rider is placed on its back which leads to additional weight bearing on the feet and the horse now begins to work. Training may lead to abnormal stresses being placed on an underdeveloped foot along with excessive wear to the feet. The animal begins to show discomfort and shoes are then placed on the feet for protection. It has been discovered that the horse has receptors in the bottom of its foot and it is speculated that these receptors function in a stimulatory capacity1. So the first thing that happens when shoes are applied is that these receptors lose contact with the ground. Next we need to take into account how the foot is being trimmed and the application of shoes by the farrier. So we see right off that the combination of the above factors can / will / often do change the structures of the foot forever, often leading to a "weak" foot that is hard to maintain without shoes (Figure 2). Prove this to yourself by taking a digital photo of a horse's foot at the start of training and then take another photo 6 months to a year later and compare the difference. Traditionally we place shoes on these youngsters too early and often it is not necessary as long as a few modifications are made in our training program so the feet can continue to develop.
Coupled with the structure of the foot is the exercise program that is anticipated for the horse being maintained without shoes. Many horses can do well without shoes as long as they are not asked to perform. Light riding may be feasible while competition may not be possible. Finally, the surface upon which the horse is kept / exercised will influence the wear on the feet. A hard surface or abrasive surface such as sand will not be as forgiving as a soft deformable footing.
The need for Traction on variable ground conditions can also dictate the choice of barefoot versus shod. Shoes in and of themselves act as a traction device as well as providing more cup to the foot. Traction devices allow horses to hold their footing, prevent slippage and improve overall performance in competitions such as eventing, jumping, steeplechase racing and polo. Equestrian sports such as fox hunting that take place during winter are aided by traction devices because of the diverse weather and footing conditions. They provide safety to the horse and give the horse confidence while performing. A factor often overlooked in the equation is that traction devices also provide safety to the rider as well, whether the person is trail riding or competing. Sliding plates in reining horses could be considered an anti-traction device as they decrease the friction between the ground and the hoof. Borium or studs provide safety from slippage to a horse when turned out in snow or icy conditions. They allow a horse to be ridden or to pull a sleigh on the snow and ice.
Therapeutic shoeing generally forms part of or sometimes the entire treatment for lameness confirmed to the foot. Lameness results from repetitive stresses or overload placed on a given structure / structures of the hoof capsule or structures within the hoof leading to damage. Shoes can be used to change the forces / stresses on a given structure within the hoof capsule and unload damaged areas of the foot. Shoes are used for realignment of the distal phalanx in the case of laminitis, they provide continuity of the hoof capsule after resection in white line disease, stabilize hoof cracks and distal phalanx fractures and provide protection following a puncture wound or foot surgery. Angular or flexural deformities in young horses may be treated or aided by various types of shoes.
A transition period is always needed when changing a horse from being shod to barefoot in order to allow the foot to adapt2. Adaptation means the hoof wall must toughen and the sole must increase in depth i.e. become thicker to compensate for not wearing shoes. Horses are much easier to maintain in a barefoot manner if they have never had shoes. It also makes a big difference as to how long the horse has worn shoes because this has a bearing on how long a lag phase can be expected before the horse develops the necessary sole protection once the shoes are off. The structures of the foot are often of inadequate mass or irreversibly damaged and thus incapable of adaptation. If a decision is made to remove the shoes, the horse should be taken out of work. We recommend a 30-90 day transition period during which time the structures of the horse's feet are allowed to toughen and adapt to being without shoes. At this point we also change the method of hoof care from trimming the foot to "shaping" the foot. The only tools necessary are a wire brush and a rasp. Nothing is removed from the bottom of the foot. Using a rasp, the heels are moved back to the base of the frog (when possible) and the hoof wall is not lowered but just rasped on an angle so a rounded edge is created. Flares or excess toe are removed from the outer hoof wall (shaping). We finish by slightly beveling the toe from the toe quarters forward to promote sole growth and to toughen the sole wall junction (Figure 3). If firm pressure (using thumb pressure or hoof testers) on the sole causes the sole to give, this bevel should not be created.
This adaptation phase can be gauged according to the initial structure of the horse's foot and should be controlled. When a minimal sole depth is present (as evidenced by hoof testers applied to the sole), the horse should be confined or placed in a small area of soft footing and then walked daily on a firm surface until the structures of the foot begin to change and adapt. Placing the horse in some form of protective boot may not provide the foot the necessary stimulation to adapt. At no time should the horse show marked discomfort as this defeats the purpose. If after 30 days, the horse's sole has not become firmer and noticeable growth of sole does not appear on the inner border of the sole wall junction, then it may be worthwhile to reconsider this method of hoof care in the best interest of the horse.
In summary, many barefoot proponents have taken an extremist view that shoes and nails start the feet on a destructive road, purporting this belief without looking at the overall scientific and physiologic picture. There are advocates of the barefoot movement that claim through their research that applying shoes to the horse is detrimental and therefore all horses need to be barefoot. This research claims that nails placed in a horse's foot are toxic, that the bars in the heels should be removed as they impinge on the circulation and that all horses should be trimmed in the same specified manner. Yet I have never been able to find this research. I have never seen a scientific publication that states nails are toxic when placed in a horse's foot. If we think of the hoof capsule as a cone – one quickly sees the necessity of preserving the bars as they provide stability and allow the hoof capsule to expand which in turn allows the normal physiology of the foot to take place. Finally, if we consider the various breeds of horses, individual foot conformation, structures of the foot, phalangeal alignment, etc, it would appear highly unreasonable to trim all horses in the same manner. As all horses are not created equal, neither are their feet. Shoes have been known to cause lameness and change the hoof capsule; shoes have also been documented to treat lameness and improve the structures of the hoof. So when we decide whether a horse can be kept barefoot (and many can't), considering the variables involved, the answer may be "it depends".