Identifying and treating thrush

Thrush is an anaerobic bacteria that dines on healthy horse hoof tissue. It grows best in low oxygen environments. Horses contract the bacteria when they stand in muddy pastures or wet stalls for hours at a time. If a horse has contracted heels, a deep cleft (central sulcus) or a frog peppered with fissures and tags, he’s at risk for developing thrush.


You can smell thrush before you can see it.

Bad cases of thrush are characterized by black goo oozing from the frog. However, if the thrush bacteria take up residence in a nice deep crack in the frog, they can live there for years undetected. Only bad cases of thrush ooze goo, but even mild cases can be painful for your horse. Watch for these three things to identify thrush:

  1. Conditions that leave your horse’s feet wet for hours at a time.
  2. Cracks between the heel bulbs, in the frog along the collateral grooves or in the cleft.
  3. The horse’s hoof smells like a poopy paddock even after you’ve picked it out.

Thrush is a stubborn bacteria to treat.

Kopper Kare thrush treatmentOnce it attacks the frog, thrush works its way deeper into the hoof to protect itself from air exposure. The bacteria can live in a tight sulcus crack through the driest summer and the coldest winter. Some people recommend using household cleaners and chemicals to treat thrush, but they are only temporary solutions. Lysol soaks and peroxide will kill the thrush but also damage the hoof tissue, leaving the frog vulnerable to a new bacterial infections.

Dominion Vet makes a product called Kopper Kare, which is a fungicide-antiseptic-astringent solution. It will kill thrush bacteria without damaging healthy hoof tissue. Here’s how to apply it: After picking out your horse’s feet, scrub the soles of the hoof and the frog with a stiff brush to remove as much dirt and debris as possible. Don’t wash the hoof – we don’t want to add any more moisture to the area. Then, squirt the solution directly onto the frog and heel bulbs. Use a cotton swap or small paint brush to work it into the clefts and cracks. Kopper Kare is water resistant, but for best results, give the product a chance to soak in before turning your horse out to pasture.

Prevention is the best cure.

Here’s how you can win the upper hand on thrush or prevent it from attacking your horse’s feet:

  • When the ground is mucky, pick your horse’s feet twice a day.
  • Add sand or pea gravel to the spots in the paddock where your horse spends the most time. These types of fills have excellent drainage, so your horse won’t be standing in muck.
  • Keep your horse’s stall clean and dry.
  • Keep a pair of kitchen shears in your tack box, and use them to trim tags on the frog between farrier visits.
  • During wet weather, apply a thrush product like Kopper Kare once or twice a week as a preventative measure.

How do you beat back thrush bacteria? I’d love to hear your tips and experience.

11 thoughts on “Identifying and treating thrush

    • Sorry, Randy, that sounds like it needs a professional’s opinion! You might want to seek a few opinions from some different vets and farriers.

  1. My hooftrimmer encourages the use of cider vinegar sprayed on hooves after picking as a preventative measure for thrush when conditions get favorable for it. She has heard the acid kills bacteria, but doesn’t dry out the hooves.

    • Yes! I have heard that too. A past farrier of mine recommended soaking the hook in a mixture of apple cider vinegar, epsom salts and warm water. It didn’t work for me – it was just more moisture on a frog that was already too soft. But it is a popular and natural thrust treatment!

      • You could also add some Melaluca (tea tree oil) or even oil of oregano. Both essential oils that have anti-fungal properties.

  2. I pour Kopper Kare into a container that comes with a brush. I find it gives better control with getting into all the crevices.

  3. Abby did the Melaluca a and oregano with the essential oils do u spry it on or a runny cream if u could let me no ty

  4. Some old guy told me use a 30% bleach and 70%/water on the thrush. Then rub in Vaseline or Vicks vapore rub. As they will keep more moisture out. And keep the bleach killing action going on.

  5. If your horse has a well trimmed foot that is functioning properly, unlike the one in the photo that is full of false sole and in need of some knowledgeable care, there won’t be issues with thrush. A healthy functioning foot doesn’t have cracks, crevices, contracted heels or deep collateral grooves that are perfect homes for bacteria to thrive. I always tell new clients that if you have thrush, there are more often than not bigger problems to deal with. Always go to the source of the issue. Thrush can be treated constantly but if the trim and hoof care never changes, it will come back time and time again.

    • Not all horses are blessed with perfect feet, no matter how well or how often they’re trimmed. Just as with athlete’s foot, some horses and ponies are just more susceptible than others.

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