What happens when equine feet are neglected, or environmental conditions are less than ideal? The hoof is under constant assault from arid conditions, wet conditions, bacteria, fungi, and physical trauma. We will continue to address common hoof diseases here.
In the previous post, we introduced the basics of hoof anatomy and care. The first ailment we covered was white line disease. In this post, we will discuss thrush and abscesses.
Like white line disease, thrush occurs in wet environments, contaminated with manure and urine. This can be from excessive rains or snow leading to a very muddy pasture, or from a horse confined to a wet stall. Horses tend to be less active in the winter, leading to a degeneration of the frog and buildup of wet material in the sulci. Secondary fungal infection with Spherophorus neaophorus leads to further destruction of the frog, producing the characteristic foul odor every horseman dreads.
The good news is that thrush is treatable with proper management. The first order of business is to clean up the foot. Work with your farrier to ensure proper hoof trimming. The normal flexion of the frog and heel bulbs act to clean the sulci with every step. Let the horse help clean his own feet. In exchange, you must provide him with a clean, dry environment to prevent further damage.
As for “treatment”, there are many, many commercial products available on the market to battle the fungus. None will be effective if applied on top of a dirty frog. Thoroughly cleaning the hoof before treatment is imperative. The solution must penetrate into all the cracks and crevices of the frog to target the fungus. Once the infection is under control, and the hoof remains clean and dry, new frog will regrow.
Abscesses are often cited as the most common cause of acute lameness in horses. Subsolar abscesses occur most often. Bacteria or fungi penetrate the hoof capsule through cracks in the hoof wall, a puncture wound to the sole, or through the white line. Once inside, the bacteria begin to replicate and start the inflammatory cascade. Responding white blood cells attempt to eliminate the bacteria, leading to necrosis of surrounding tissues. The necrosis is walled off, forming the abscess. Inflammation and destruction of tissues within the confines of the hoof capsule leads to the pain, swelling, and lameness commonly associated with hoof abscesses.
Degrees of lameness range from subtle to acutely non-weight bearing. Observant horse owners will note heat and digital pulses in the affected foot. Your veterinarian will use hoof testers to localize the pain to diagnosis the abscess. Rule outs include laminitis, stone bruise, or P3 fracture. Radiographs can help with diagnosis. If left untreated, abscesses can invade other structures of the foot, such as the coffin bone, tendon sheaths, or collateral cartilages.
Like an abscess under the skin, a hoof abscess needs to be opened and drained. A poultice can be used to help soften the area and draw the infection to the surface. The veterinarian often starts the horse on systemic antibiotics and anti-inflammatories after drainage. Tetanus vaccination should be boostered if the horse is not current. Bandage changes and stall rest may be required to keep the foot clean and dry, preventing reinfection.
White line disease, thrush, and hoof abscesses are easier to prevent than treat. Work closely with your farrier to maintain proper hoof trimming. Practicing daily hoof cleaning and maintenance allows problems to be noted early, and corrective measures began before problems arise.