Equine Thrush: What Causes the Odor?

Farrier working on case of Equine Thrush

A strong rotting smell is a well-known indicator of Equine Thrush. You probably know the smell well if you’re a horse owner. The smell is like that of a rotten egg. The odor radiates from the hoof, making regular hoof cleanings and farrier work more foul-smelling than usual. So, what causes Thrush to smell? In this blog, we sniff out the answer to this question.

Hoof Anatomy and Structure

Your horse’s hooves are comprised of connective tissue proteins. Connective tissue is rich in the mineral sulfur. The sulfur provides the “welds,” or crosslinks, in the connective tissue protein. These crosslinks are responsible for the structural integrity of the hoof capsule. If the bonds are weakened or destroyed, the structural integrity of the hoof will be compromised.

Thrush and the Microbial Invasion

Thrush is an invasion of “hoof-eating” microbes into the connective tissue of the sulci surrounding the frog and heel. These anaerobic microbes thrive in low oxygen environments, such as the deep sulci and clefts surrounding the frog. Once the organisms divide in the frog sulci, the stage is set for a progressive invasion and infection.

How Equine Thrush Affects the Hoof

The anaerobic microbes consume the connective tissue proteins, including the sulfur, and excrete volatile sulfur compounds as waste. The rotten egg smell associated with Thrush is the odor of the sulfur released by the microbes. The same smell occurs during hot-shoeing. The odor produced is the smell of sulfur gas from burning the sulfur-rich connective tissue proteins of the hoof.

Thrush can be devastating to the hoof. As the sulfur crosslinks are destroyed the connective tissue becomes weakened, compromising the structural integrity of the hoof.

If your horse develops Equine Thrush talk to your veterinarian and farrier. Use a non-caustic hoof topical, such as Life Data® Hoof Clay® and Farrier’s Finish®, as a measure against Thrush. Stay away from caustic remedies for Thrush or substances that block oxygen to the hoof. Add a balanced hoof supplement, such as Farrier’s Formula® Double Strength, to your horse’s diet to build a stronger hoof capsule more resilient to infections and other hoof related issues. Contact us at 1-800-624-1873 if you have any questions.