What exactly is thrush and how does it affect horses? Thrush is a bacterial infection of the grooves of a horse’s frog and hoof. Horses with deep grooves next to the frog or between the heel bulbs may be more prone to developing thrush. Most cases of thrush are seen in horses kept in damp and muddy conditions, though cases are also seen in horses kept in dry conditions.
When cleaning out your horse’s feet, you can recognize thrush by its foul smell and black oily discharge. The sole tends to become crumbly when scraped and, in severe cases, the horse may bleed or resent having their feet picked out.
Thrush is most often caused by bacteria, with the most common cause being Fusobacterium necrophorum, which is found in wet conditions with low levels of oxygen. While thrush rarely causes lameness, severe infections that have penetrated deeper sensitive tissues of the foot can be painful.
Prevention is generally achieved by keeping horses in a clean and dry environment with daily hoof cleaning to remove debris and allow oxygen to reach the area. Regular farrier trimming will also help keep the hoof free from excess growth and allow for healthy wear. Even with diligent care, thrush can develop, but mild cases are fairly easy to treat. Twice daily hoof picking and bedding in a clean, dry stall are key. Soaking affected feet in warm water with diluted betadine before scrubbing the grooves helps to kill the bacteria and remove any discharge. After cleaning, dry the feet and apply a commercial thrush treatment such as Thrush Buster. You should always consult your veterinarian to determine the best treatment for your horse.