It's a rare horse owner won't have to deal with thrush at some point. Mild cases of thrush generally respond to over-the-counter or homemade remedies, along with horse-keeping management changes and farrier care. Severe cases of thrush, including any causing lameness, require veterinary assistance.
Signs of Thrush
Thrush occurs in the frog, that triangular-shaped, weight-bearing structure behind the sole. The frog has two grooves, or sulci, forming a V, with a shallow indentation known as the central cleft in the center. It's important to keep those grooves clean, so thrush can't gain a foothold.
If your horse develops a dark, smelly discharge in the frog, he's got thrush. Even if you clean his hooves daily, thrush can develop if he spends most of his time in a moist environment, whether that's a dirty stall or a muddy paddock. Horses with certain types of hoof conformation, such as contracted heels, are more likely to experience thrush.
Call the Farrier
If your horse is soon due for a trim or shoeing, the farrier can cut away areas of dead tissue and get rid of crevices where the fungal infection lurks, exposing it to air. If your horse isn't due for a trim or shoeing for a few weeks, call your farrier and make a special appointment.
You might be overwhelmed by the various thrush treatments available at your local tack shop or at online equine retailers. These products might contain ingredients such as copper sulfate or gentian violet. If you're not sure which product to use, ask your vet for a recommendation. Follow the directions on the container, and use gloves when applying the medication.
Many time-honored home remedies will clear up thrush just as efficiently for far less money than commercial products. Always clear any homemade remedy with your vet before concocting and using it. For generations, horsemen have eradicated thrush using bleach diluted with water -- generally 1 part bleach per 10 parts water. Diluted povidone-iodine is another effective treatment. For best results, soak cotton balls in the remedy daily and push them into the the central cleft with a hoof pick. You can try placing the cotton balls in the sulci, but unless the infection is quite deep they will fall out. You must simply brush or pour the remedy into the sulci, but take care not to get the solution onto your horse's skin, where it may sting. After a few days of treatment, you should see results. If the thrush doesn't improve or worsens, contact your vet. Your vet might prescribe special medications, including antibiotic pastes, to place in your horse's feet. It's still a matter of daily cleaning and treatment application until the condition improves.