Did you notice anything different the last time you picked your horse’s feet? If you caught a nasty odor and saw a black, putty-like substance on your pick, here’s what could be wrong.

The word: Your horse most likely has thrush, a bacterial infection that thrives in anaerobic (no-oxygen) conditions. Thrush is common in horses kept in muddy or otherwise moist conditions, such as uncleaned stalls or pens. It’s also seen in horses that wear protective pads under their shoes. It varies in severity, and can become severe enough to cause lameness if not treated promptly.

While commercial and homemade anti-thrush compounds are available, you’re smart to consult your farrier (and/or veterinarian) before embarking on do-it-yourself treatment. The affected hoof areas may need to be pared away, and the best choice of treatment compounds will depend on the severity of your horse’s case.