Table of Contents

Cannon Crud

What is Cannon Crud?

Cannon crud goes by many names but is the same condition—a waxy, greasy appearance on the front of the rear cannon bones. The exact cause has not been determined. Diagnosis is visual, and there are many methods to treat it but no actual cure.

The good news?

Cannon crud is generally cosmetic in nature and does not actually bother your horse.

Cannon Crud is also known as...

Cannon crud has a lot of other names; stud crud, “leg funk,” urine scald…all of these refer to the same condition. 

But the cannon crud does have a scientific term known as cannon keratosis. It presents as waxy paste, visible on the front of the rear cannon bones. Also known as seborrhea, cannon crud is a flaky and scaly condition of the skin. It is caused by the glands overproducing skin cells. It affects all breeds, genders, and can show up at any age. While the exact cause is unknown, it is thought some horses may be genetically predisposed to the condition.

Horses have cannon bones in both the front and hind legs; cannon crud is only seen on the front part of the hind legs.

Cannon keratosi is caused by the sebaceous glands overproducing sebum. Sebum is the oil that helps create shine in the horse’s coat and contains antibacterial properties to protect the skin. When it is overproduced, it creates a waxy, scaly patch on the horse’s skin.

How to diagnose Common Crud

Visually, cannon crud causes a waxy, scaly appearance of the skin on the front part of the cannon bone on the rear legs. It is localized to this area, not contagious, and should not spread to other parts of the body.

Seborrhea is defined as excessive discharge of sebum from the sebaceous glands. In people, seborrhea dermatitis is very common. When it affects the scalp, we call it dandruff. Seborrhea in horses exists in both primary and secondary versions. Primary seborrhea is found on the front of the cannon bone on the hind legs—cannon crud. Unfortunately, this is not the only place it can be found; secondary seborrhea can be found on other parts of the body and is associated with an infection of the skin, oily, or dry skin.

Cannon crud is not a fungus, virus, or bacteria

It is not caused by urine and is different from scratches. This condition is simply the body over-producing skin cells in this area. 

While cannon crud can be relatively easy to diagnose, it is commonly confused with other skin conditions such as rain rot or sweet itch. It is always a good idea to consult your veterinarian to ensure what you are observing is not something more serious.

Symptoms of Common Crud

Primary and Secondary Locations

The primary location where cannon crud occurs is the front part of the rear cannon bones. However, a secondary infection (secondary seborrhea) is possible. Some horse owners reported observing cannon crud like symptoms on other areas of the horse’s body, specifically the face. Secondary seborrhea is also linked with nutrient deficiencies or liver disease and should be explored more thoroughly.

Common Crud Cause: Unknown

While no direct cause is known, maintaining good hygiene for your horse is always important. Some people associate wet, muddy conditions as a cause, and stress that the importance of thoroughly drying your horse after baths or treatments for the cannon crud.

Others suggest that sweaty, wet splint boots or wraps can cause common crud, and help make the symptoms worse. However, one cause of confusion is that horses living in the same conditions do and do not get cannon crud; this leads horse owners to believe that some horses are just genetically predisposed to it.

If you ever observe heat, swelling, hair loss, or discomfort in this area, you should immediately consult a veterinarian—these symptoms are not typical of cannon crud.

Treatments for Common Crud

Cannon keratosis, or crud, can be managed through various grooming practices. There is no specific cure, but a lot of information can be found online offering different types of treatments. This is both good and bad; if something doesn’t work, there are lots of other options to try. On the other hand, it may take quite a bit of trial and error to figure out what will work best for your horse. Some horse owners report different treatments working on different horses within the same barn; unfortunately, there is no one-size-fits-all approach.

Washing & Grooming the Area

Washing with a mild shampoo. Grooming gloves and soft brushes are highly recommended for this area of the horse’s legs, as it is skin over bone and more sensitive. Aggressive grooming can cause more harm than good.

Overzealous grooming could cause the skin to break, leading to a bacterial skin infection.

Too much attention to this area can cause cellulitis, a more serious bacterial skin infection which can lead to swelling (sometimes quite substantial), fever, and lameness.

If over-the-counter shampoos aren’t cutting it, your veterinarian may recommend a medicated shampoo, likely containing benzoyl peroxide.

Some Horse Owners Ignore Common Crud

Several horse experts recommended simply ignoring this condition; it is generally not harmful or uncomfortable to the horse.

If you have a show horse, simply ignoring this condition may not cut it—especially halter and showmanship horses need to be turned out demonstrating perfect grooming, and tufts of oily, scaly skin on the legs detract from the overall appearance.

Recommended Products to fix Common Crud

Several products were referenced repeatedly by equine professionals. These include:

Shapley’s MTG (Mane Tail Groom) is a popular solution. It treats a variety of bacterial and fungal skin problems, but also could help with cannon crud.

Krud Zapper was mentioned several times on different websites as an effective treatment for cannon crud.

Vetricyn, while noted as a little more expensive, was also mentioned numerous times by horse owners trying to find solutions for this condition.

How to Prevent Common Crud 

Unfortunately, the root cause of cannon crud is not known, making prevention is difficult to define. Good hygiene and grooming never hurt though. Ensure your horse has access to shelter in wet conditions and groom regularly so any abnormalities can be caught and dealt with quickly.

One common myth is that cannon crud, or “urine scald” is caused by urine splashing up on a horse's rear cannon bones. This is not true—mares are also susceptible to cannon crud and there is no link to urine and this skin condition.

While cannon crud can be annoying and unsightly, it is generally harmless to your horse. There are a lot of relatively inexpensive products that have reported success in treating this condition. Always consult your veterinarian before trying any new treatments, or if the condition worsens.