Thrush is a foul-smelling, bacterial hoof infection in horses that can strike no matter where you live. While horse manure may be unpleasant, thrush takes the title for one of the worst odors—and it’s far more serious. This hoof condition thrives in wet, muddy environments and can lead to lameness if left untreated.

In this quick guide, we’ll explain what causes thrush in horses, how to recognize the early signs, and the best ways to treat and prevent it. With proper hoof care and prompt attention, you can protect your horse’s hooves and keep them comfortable, healthy, and ready to ride.

Quick Facts About Thrush in Horses

• Thrush is a bacterial and fungal infection which often results from living in wet, muddy conditions and poor hoof picking habits.
• Thrush is best treated with a combination of removing as much of the infection as possible and regularly cleaning the site with a clinical solution.
• Thrush is best prevented by regularly picking horses’ hooves, keeping their stalls, paddocks, and fields clean and dry, and having their hooves inspected and worked on by a qualified farrier.

What is Thrush in Horses?

Thrush is a bacterial and fungal infection which degrades horses’ frogs and creates secondary bacterial infections in the central and collateral sulcus. Typically, it affects horses’ central sulcus if they have sheared heels, whereas lateral sulci are primarily affected in most cases of thrush. Conformational issues such as long toes/low heels will create heel collapsing/contraction which traps in moisture/bacteria. Horses with lameness at the toe will shift weight back on the heels, creating again heel crushing and contraction. What does a horse hoof sulcus look like?

What Are the Symptoms of Thrush in Horses?

Symptoms of thrush include an absolutely putrid, rotten smell and a black, tar-like discharge that comes from the hoof. Thrush most commonly affects the hind hooves rather than the front, largely because these hooves are more challenging to clean thoroughly. As a result, debris often remains lodged in the sulci (deep crevices and the depression near the heel at the center of the frog). Additionally, the steeper angles of the hind hooves make them more prone to trapping moisture, mud, and manure—creating an ideal environment for bacterial growth. If left untreated, thrush can progress beyond the hoof and begin to affect the lower limbs.

Over time, untreated thrush can cause a variety of unseemly and dangerous symptoms. Symptoms of severe thrush can include a recession of the frog, increased weight bearing on the affected heel, and eventual lameness.

Does Thrush Hurt Horses?

Thrush does not typically cause pain by itself.  However, given that thrush can eat its way into and expose the frog’s sensitive tissue underneath, it can be easy for horse owners to unknowingly pick the exposed area too deeply and cause their horse pain. At times the tissue may even bleed. This would indeed be the case if the horse’s (protective) frog has already been compromised and minimized by thrush. In this case, the protective frog is almost nonexistent. Imagine your car without its shocks, that’s what it feels like to your horse. Moreover, horses who have narrow, upright feet and are more likely to have a closed up sulcus and a deep cleft between the heel bulbs; they may experience additional discomfort due to a thrush infection.

What Causes Thrush in Horses?

One cause is lack of exercise which helps clean out the sulcus.

Thrush is an infection that is most often seen in horses who live in a wet, muddy paddock. However, the idea that “horse living in muddy conditions = guaranteed to get thrush” is not entirely accurate. It can be found in horses living in perfectly clean conditions, and sometimes it’s only found in one hoof when the horse is living in poor conditions.

Thrush is likely caused by a couple of compounding factors. Namely, a combination of wet and muddy living conditions as well as poor foot conformation, poor trimming, and a lack of exercise. This last point is especially important, as exercise can help clean out the sulcus when the horse puts his weight down on the frog. This may prevent a thrush infection from taking root in the hoof.  Here’s how it works. As the frog experiences a mild concussion from a normal hoof contact to the ground, dirt and debris are expelled from this area, keeping it cleaner. Regardless of whether the horse is being exercised, their feet should be picked/cleaned out every day. Correct hoof care practices are always the first defense.

How to Treat Thrush in Horses

To treat thrush at home, begin by moving the horse into a dry environment. Then, you or your farrier will need to debride the frog and sulcus to reveal the infection. From there, farriers will clean and pick out the black debris from the hooves. If the dirt and muck won’t budge, the farrier may flush out the frog with water and hydrogen peroxide before using a wire brush on the area.

Once the mud and muck has been removed, the infected area must be cleaned with a thrush treatment solution such as Sore No More-The Sauce or Banixx Horse Spray. Banixx is an antibacterial and antifungal treatment that provides instant, sting-free and odor-free relief. And, it’s clear, it has no color so it won’t stain your hands or your horse. Sore No More-The Sauce is a liniment that helps heal hoof conditions by drawing out heat, toxins and fluid.

These products are in stark contrast to many other thrush treatments that contain iodine or bleach. Repeated iodine treatments will eventually burn your horse’s tissue causing pain. The resultant pain makes treatment more difficult or even dangerous for you. Moreover, bleach will dry out your horse’s hoof tissue. Healthy hoof tissue needs an adequate moisture level to remain pliable. Both conditions will make the tissue in the hoof overly sensitive to treatment

How Long Should I Treat My Horse?

After this initial treatment, horses with thrush will need to continue to receive treatment until the infection is gone. To ensure that it doesn’t return, the horse’s farrier must properly manicure and trim the horse’s hoof so they can evenly distribute weight across their hoof’s surface. Doing this will encourage the frog to grow back strong and healthy. The frogs themselves should also be trimmed in a manner that while the clefts may remain somewhat deep, the frog isn’t allowed to grow to a point where it is overlapping. This promotes self-cleaning of the clefts during a horse’s outside activities, including walking, exercising, playing, working, etc.

Over the next several weeks, continue to pair your horse’s trimming with repeated applications of treatment solution. First, pick/clean out your horses feet and then spray Banixx on your horse’s hoof just twice a day. Once in morning and once at night. This is enough to provide substantial relief and protection from thrush infections. An alternative is to apply a boot to your horse’s hoof. Fill it with enough Banixx that the infection is awash in Banixx. Soak this way for 10 minutes. If you’re doubtful about the cleanliness of his environment, tape up his hoof with a little layer of gauze. Then duct tape or vet wrap overnight.

How to Prevent Thrush in Horses

Be sure to clean the area weekly to minimize the buildup of manure or other muck.

The best prevention for thrush in horses is to clean your horse’s hooves and…often. Make sure to thoroughly clean the sides of the frog, as well as the frog itself. This will ensure your horse’s hooves are as clean as possible. If your horse is sensitive, you may be able to remove most hoof debris with a small wire brush. Never DIG into your horse’s hoof to remove hoof rubbish…persuade its removal gently.

Taking extra care of your horse’s surroundings will also help prevent this type of infection. If your horse lives in a stall, be sure to keep the bedding dry and clean. Or, if your horse lives in a run-in shed, make sure to clean the area weekly. This will minimize the buildup of manure or other muck. If your horse lives outdoors, make sure to be diligent with manure removal. Also, ensure there are adequate dry places for him to stand.  For turn out sheds, pick out manure once a week to remove wet organic material. In horses prone to thrush or in a thrush case, bed the stall in pine shavings, which helps to suck out the moisture of feet and that can aid in clearing and avoiding thrush.

Final Tips for Managing and Preventing Equine Thrush

Staying ahead of thrush in horses starts with regular hoof care, clean and dry living conditions, and a keen eye for early warning signs. Whether you’re caring for a performance horse or a backyard companion, knowing how to prevent and treat thrush is essential to maintaining healthy hooves and overall soundness. By taking proactive steps and using proven treatments, you can help ensure your horse stays comfortable, active, and free from this common—but preventable—hoof infection. If you need help with managing thrush in horses, call us at 800.786.4751.