Horse Illustrated Magazine

Q:

What is the fungus horses get on the front of their cannon bones on their back legs and how can I get rid of it?

A:

I believe what you’re referring to is technically called Cannon Dermatitis or Cannon Keratosis. It’s also affectionately known as “cannon crud” or even “stud crud.” However, it’s not caused by a fungus, and it’s not just seen in male horses. This crusty, greasy … “ick” on the front of some horse’s cannon bones is an inflammation of the skin (that’s where the word “dermatitis” comes from) that has as a component horny skin growth (that’s where the word “keratosis” comes from). It’s not infectious or contagious, and it can appear in either gender, all breeds, and just about any age of horse. Is there a genetic predisposition? Maybe, as some horses seem to get it while others living in the same environment, eating the same food, and doing the same work don’t seem to get it.

Just to be sure what you’re dealing with though, I highly recommend that you point it out to your veterinarian the next time he or she is at your barn. That’s because many skin conditions can look the same and you and your horse might get a little frustrated if you’re treating one thing (like rain rot or scratches) but it’s actually something else. Plus, if it’s a more serious dermatological issue, you’d want to start treating that appropriately right away rather than delay proper care.

Your veterinarian may suggest a regimen for cleaning your horse’s legs then applying a topical product to help them stay clean. The good news is that there are a lot of products and protocols that help keep this condition at bay; the bad news is that there are a lot of products and protocols that help keep this condition at bay. What that means is that it may take some trial and error before you stumble upon the best method to clear up the condition in your horse. Word of advice while you’re experimenting though: avoid being too aggressive by using products not designed for the skin or by physically aggravating the site by excessive scrubbing or picking as you might make things worse. Keep calm and clean on!