Preventing and Treating Thrush

One of the most common hoof ailments in horses is thrush, a bacterial condition caused by standing in wet or dirty conditions, insufficient exercise, genetic hoof deformities and sometimes,  perfectly normal everyday equine life. The bad news about thrush is that the bacteria that causes it, Fusobacterium Necrophorum, is omnipresent, residing as it does in the intestinal tract, in soil and in feces, and winding up anywhere horses tend to  congregate. The good news is that thrush can be treated and cured. Best of all, thrush prevention seems to be an issue of good hygiene: daily, thorough hoof cleaning and regular hoof care is the best prevention of all.

 

Fusobacterium necrophorum  is an anaerobic bacterium, meaning that it cannot live in the presence of oxygen. Anaerobic bacteria thrive in the depths of manure and mud, so that horses whose stalls aren’t cleaned often and well will be more prone to developing thrush infections. Overgrown toes, contracted heels, inappropriate hoof trimming and shoe pads may all contribute to thrush. Thrush appears in the central sulcus and grooves of the frog, where the crevices of the frog allow material to accumulate. When the crevices are impacted with dirt or manure, the bacteria goes to work, breaking down the layers of the frog.

 

The most identifiable sign of thrush is the smell, variously described as foul, disgusting, or revolting by those who know. The accompanying discharge is black and oily. There may be tenderness or pain, depending on how long the thrush has been present, but in new cases, your horse won’t be in pain.  If thrush goes untreated, the frog may bleed: there may be pus and swelling and the horse may eventually go lame as the frog is destroyed. Early treatments are topical, but internal antibiotics may be necessary if the infection has become systemic. (If the hoof or leg are swollen or hot to the touch, the infection has spread).

 

Thrush treatments have three prongs:

 

1. Stabling must be kept as clean as possible. Bedding should be replaced frequently; washing down floors with antiseptics may help kill resident bacteria and reduce the chances of reinfection.
2. Hooves must be picked out and cleaned daily, and hooves trimmed regularly. You may need to have the necrotic tissue trimmed by a farrier when starting treatment. Some vets suggest using soaking solutions to help kill bacteria that’s worked into the hoof crevices.
3. Applications of antibiotics ointments or liquids follow daily hoof cleaning until the thrush has disappeared. The product should be thin enough to be worked into the crevices using a swab, but thick enough (or sticky enough) that it doesn’t wash off right away. You may decide on a daily soak, using soaking boots.

 

Everyone has their favorite thrush remedy, from dilute cider vinegar to solutions of bleach, peroxide or formalin (Formaldehyde). Depending on your tolerance for high-potency or frankly dangerous substances, you may decide on a product that leans heavily on copper napthenate or choose something containing a safer antibiotic such as tea tree oil.

 

Although experts may disagree on the best thrush remedy, most do agree that exercise is important in preventing thrush. In horses with normal hoof conformation, weight bearing activity actually presses foreign material out of the hoof and helps keep it clean. For horses recovering from thrush, exercise is also important, as it helps increase blood flow to the frog, which speeds the healing process.