Thrush Infection Basics

Thrush Infection Basics

Thrush Infection Basics

By Greg Toronchuk

Q    My horse gets thrush every winter despite my best efforts to prevent it. What do you recommend to prevent and treat thrush?

A    Thrush is a common hoof disease which usually has a simple treatment with little or no long lasting implications. However, in some situations, infection left unaddressed can cause long-term lameness. The collateral sulci (the grooves alongside the frog) and the central sulcus (groove in the center of the frog) are the main sites of thrush infection. These are the areas where your horse may become sensitive to a hoof pick or, in extreme cases, sensitive to manual palpation with your finger.

The two main culprits which cause thrush infections – anaerobic bacteria and fungi – are common in nearly all soils and flourish in oxygen deprived environments. It is nearly impossible to keep a paddock or stall free of thrush causing bacteria and fungi, but there are important elements to keep in mind for reducing the likelihood of thrush occurrences. A dry area free from straw bedding is important. Urine breaks down straw very rapidly, creating a favourable environment for thrush causing agents.

That being said, thrush can infect your horse’s hooves even with a perfectly dry paddock. Environment is only part of the thrush equation. Hoof condition is equally important.

horse hoof parts

Parts of the Hoof

Deep sulci with overgrown frog creates the perfect microenvironment for a thrush infection. I like to keep the sulci open so they stay as clean as possible. Club feet tend to have a higher incidence of thrush, as do hooves with a coronary band injury or deformity.

The severity of a thrush infection can vary from just a little black residue on the end of a hoof pick when cleaning out feet, to bleeding and eroded corium as a result of a severe infection.  Because I am diligent at keeping my frogs trimmed up, I rarely see bad thrush infections and when I do, usually moving a horse to a drier paddock or fixing a leaky water line is enough to clear up a lingering thrush problem. For the few horses that need a little extra help I use a product containing iodine.

I first remove all infected tissue, which will allow more oxygen to invade the infected area. Then, after a thorough trim, I will have my client apply the iodine product to the infected areas daily until the symptoms subside. There are many other products marketed for thrush treatment available, as well as natural mixtures you can make up at home. Always consult your farrier and veterinarian before starting a thrush treatment.   

Greg Toronchuk, BSc Ag, has been a professional farrier for five years, having gone to farrier school in the U.S. after finishing a degree in Animal Science from the University of Alberta. He shoes mainly hunters, jumpers, and eventing horses, but has a few clients from nearly all disciplines in his books. The Alberta representative for the Western Canadian Farriers Association, Greg believes in continued farrier education and attends clinics and lectures, as well as competing in horseshoeing contests across Canada.

Main Article Photo courtesy of No Thrush - Deep sulci with overgrown frogs and heel cracks create the perfect microenvironment for a thrush infection. Removing the infected tissue allows more oxygen to invade the affected area.

This article originally appeared in the December 2012 issue of Canadian Horse Journal.

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