Thrush is a common pain-in-the-neck ailment. It’ll normally respond rapidly to correct treatment (the classic ”squirt and done” routine rarely works) and, like everything else, it’s best if you catch it early.
Pick your horse’s feet daily, and watch for the initial signs of thrush (see sidebar on page 4). It’s best to eliminate thrush in its early stages, before the infection can invade deeper tissues or between the heel bulbs. Once it’s set-in, it’s more difficult to treat and can even make your horse lame.
Bacteria, Not Fungus. Thush is a mixed bacterial infection in the grooves along the side of the frog, in the central cleft of the frog and/or in the crease between the heel bulbs. It usually involves the organism Spherophorus necrophorus (aka Fusobacterium necrophorus). It is an anaerobic organism, which means it requires a low-oxygen environment to grow. Although this organism is capable of invading skin, it usually requires other bacteria to do so effectively. Exactly how this works isn’t completely understood, but one theory is the other bacteria will keep the oxygen level low enough for S. necrophorus to survive.
Causes. Manure can serve as a source of bacteria, including S. necrophorus, and manure packed into the bottom of the foot also creates a low-oxygen environment. However, the horse doesn’t have to be standing around in manure to get thrush. Muddy conditions also favor thrush because the organisms can survive in moist soil. Mud packed into feet also seals them off from the oxygen in the air.
Improperly trimmed frogs grow flaps that cover the grooves, lowering oxygen and trapping moisture. Feet/heels that are too long also predispose to thrush because the grooves become very deep and the hoof does not self-clean efficiently. Finally, injury to the tissues from embedded stones or other materials will break through the normal barriers and allow bacteria easy access.
Hoof Preparation. First, thoroughly clean out the black material. Pick out the foot, then use a stiff brush to remove all the debris until it’s clean. You can wash it out, too, but be certain that you rinse thoroughly (see sidebar, page 4, mixing products) and dry the hoof.
Once the foot has been cleaned and thoroughly dried, apply your treatment. Packing the sides of the frog with cotton soaked in the product and pushed firmly into place with a hoof pick will give prolonged treatment.
Note: Before any product can help, it must be able to get to the organisms. If there are overhanging flaps of the frog, get your farrier out to trim that back or, if you’re comfortable doing so, cut them off yourself. He or she also may be able to trim away a lot of the affected tissue, making your job easier and offering a faster recovery rate.
Our Trial. This is a two-part field trial. In this first section, we’re focusing on botanical ingredients (botanical/natural ingredients only or mixed chemical and botanical). Next month, we’ll discuss the heavy guns: chemical and pharmaceutical treatments. (Note: You’ll also see thrush discussed in the near future when we look at products that are designed to eliminate hoof or skin infections.)
In this trial, we define mild thrush as the obvious black discharge and odor but no lameness or pain on picking the feet and no deep-tissue layer invasions. Moderate thrush is defined as pain on picking the feet or manipulation of the tissues of the heel. Severe thrush is severe pain with obvious involvement of the deep tissues, e.g. tissue with deep cracks or, sometimes, bleeding.
If you’re determined to avoid chemicals (unless absolutely necessary, of course), Kiss A Frog and Thrush Off were the only products free of chemical ingredients in both their base and active ingredients. Also, all the ingredients in HoofSeptic are easily biodegraded and harmless to the environment.
However, we must caution you that ”chemical” doesn’t necessarily mean more harsh or less environmentally safe. For the antimicrobial compounds in botanicals to be effective, they have to be isolated and in a concentrated form. Many concentrated essential oils are highly irritating to skin, eyes and the respiratory tract. Their environmental effects are unknown, but they can’t be assumed to be zero. There are also botanically based products with potentially hazardous carriers. Read all product labels.
Bottom Line. The key to treating thrush is diligence. Stay on top of it, follow instructions, and keep the hoof clean and dry. Apply the gentlest topical that will be effective against the degree of severity.
All the products in this trial were effective for mild thrush. The most effective products for mild-to-moderate thrush were Huuf Magic and Solution4Feet. However, our top choice and Best Buy is Huuf Magic. It’s about half the cost and its ingredients are made known to you.
For severe thrush, there’s only one choice: Thrush Off. It’s the only product free of potential sensitivity problems when used on raw, open tissues, and it’s effective.
Article by Veterinary Editor Eleanor Kellon, VMD.