A problem we see in our practice quite frequently is a horse with a bruised sole. There are many causes of bruising including using a horse on hard or rocky ground that has soft soles. Also, some horses can be shod incorrectly and a shoe can pinch the sole and cause pressure or the horse can be trimmed too short and cause bruising. The sole is not designed to support weight and flat-footed horses are prone to chronic bruising. Some horses also have thin soles, and these horses are susceptible to bruising when used on hard ground.
For many years treatment of subsolar bruising has involved soaking the foot to supposedly draw out or relieve inflammation. However, Dr Steve O’Grady, an equine podiatrist, indicates that soaking the foot for more than 2 to 3 days can actually worsen the problem by softening the sole and decreasing the its protection. Foot bruising is commonly seen in show horses that are bathed continually as the excessive moisture weakens the hoof wall. As the wall weakens, cracks develop and the sole gets closer to the ground and increases the chance of bruising.
Dr. O’Grady mentions that the treatment for bruising should be just the opposite. Instead of softening the sole with soaking, we should instead try to toughen the sole for protection. The horse should be placed in a dry stall to promote drying of the sole and a product designed to toughen the sole such as formalin and iodine mixtures can be used topically. Some of these deep bruises take a long time to heal but these bruised areas should not be opened with a hoof knife like an abscess, as this will only cause further pain and delay healing.