Thrush

Written, curated, and posted by Bo Cruz

As winter snow and spring rains continues to be upon us for the next few months, an area to watch carefully in our mules is a bacterium that develops in and around the frog of their hooves called "Thrush."

Thrush is the destruction of a portion of the equine's hoof called the frog. This destruction is caused by an anaerobic bacteria and fungi that is not contagious. Thrush, however, brings with it a recognizable, strong-smelling odor coming from the affected area.

Thrush can be very painful for all equine when the frog's tissue becomes inflamed and overrun with bacteria. Typically, Thrush is characterized by a thick black discharge that smells like rotten dairy...or "poop"! This foul odor and thick discharge occur because the bacteria are actually fermenting within the frog's tissue.

This bacterium doesn't cause lameness until it eats away at the frog and gets down into the sensitive tissue, which can then cause lameness. Severe Thrush, however, often occurs in the cleft between the heel bulbs where it can turn into a deep gash.

Veterinarians recommend hooves be kept clean periodically. If the mule (or horse) is kept in a run-in shed or stall, the area should be cleaned weekly to help minimize the buildup of organic matter (manure). 

Keeping hooves clean of dirt, debris and excess moisture is the best way to prevent thrush. Standing for extended periods of time in wet areas (mud, swamps, snow, wetlands, etc.) can result in Thrush.

Thrush treatment can be relatively easy and inexpensive when especially if caught early. Kopertox and Thrush Buster can work well for treating Thrush. Scott Morrison, equine podiatrist at Rood and Riddle Veterinary Clinic, identifies and talks about treating thrush in equine in the YouTube video “Identifying and Treating Thrush in Horses.”