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  • Abi Kroupa

Recognizing and Treating Thrush in Horses

Horse Thrush usually refers to a bacterial (occasionally fungal) infection of the horse's frog, the V-shaped structure between the sole and the heel on the bottom of the hoof. As the condition progresses, the frog tissue deteriorates and produces a smelly discharge.

If dealt with early, thrush can be simple to treat. But if ignored, thrush can cause sensitivity and lameness as it eats away at the frog's tissue.

A healthy frog is well-formed and serves as a shock absorber, aids in traction, protects the digital cushion and deep digital flexor tendon above it, and evenly shares hoof load-bearing with the other hoof structures. A healthy frog also has a natural self-cleaning function. When the frog meets the ground, it expands, and the horse's weight pushes the surface of the hoof sole flat and slightly outward. The mechanism of hoof load-bearing naturally pushes the dirt and debris out of the frog sulci (groves and deep crevices near the heel and at the center of the frog).

Healthy Horse Frog

Diagnosing Frog Thrush

An unhealthy frog is recessed from the surface level of the rest of the hoof and is smaller than it should be. It can occur because of many factors, including genetics, confirmation, diet, hoof imbalance, and living conditions.

Mild Horse Frog Thrush

Meanwhile, the frog atrophies and the hoof structures deepen, allowing dirt and debris to accumulate in the groves and on the frog, creating conditions that allow bacteria and fungi to thrive. Thrush can develop and produces a foul-smelling black discharge. The hind hooves are more often affected. An aggressive infection can even result in swelling (stocking up) of the lower limbs. One type of bacteria sometimes found in hoof thrush, Fusobacterium necrophorum, can be particularly aggressive in destroying the frog tissue.

Severe Horse Frog Thrush

Thrush Source Evaluation

Though frog thrush thrives in wet, moist conditions, that is not necessarily the original cause of the infection. The best way to reduce the instances of frog thrush is to evaluate the source of the unhealthy frog. Here are a few factors to consider:

  1. Does your horse get an ample amount of turn-out (6+ hours per day) and regular exercise that allows them to utilize their frog's natural self-cleaning mechanism?

  2. Do you pick out your horse's hooves daily?

  3. Is your horse on a consistent trimming or shoeing schedule? (Every 4-8 weeks)

  4. Does your horse have any conformational abnormalities, such as a club foot or navicular disease?

  5. Does your horse live in a dry environment? (well-draining pastures and freshly bedded stall)

If you scored 3/5 or below, your horse might be at a higher risk of developing frog thrush.


Your farrier should be your first treatment, especially for aggressive thrush. They will trim away the loose and diseased frog tissue and most likely apply an initial remedy. You should continue to treat the infection with an anti-thrush product until it has cleared. Popular anti-thrush products usually include a solution with:

· Povidone-iodine or Iodine (no more than 2% solution)

· Gentian Violet

· Chloroxylenol

· Isopropanol Alchohol

· Copper or Zinc compounds

· Anti-bacterial and anti-fungal natural oils such as Tea Tree, Eucalyptus, Lemon, and Lavender

· Or a combination of those ingredients

Some horse owners opt for homemade thrush remedies. Popular solutions that can be made at home are sugardine or honeydine. These are simple pastes consisting of equal amounts of sugar or honey and a povidone-iodine solution.

Another effective yet much harsher standby treatment for thrush is diluted bleach. This solution is made with ten parts water to one part bleach and is only suggested in severe cases.

Most thrush remedies will require 7-10 days of application to clear up the infection. However, some products only need 1 to 2 applications to clear the infection. Dye-based Gentian Violet products will last longer and don't require daily application. Oil and alcohol-based solutions absorb quickly and will likely require daily reapplication until the infection has cleared.

So how do you treat thrush when your horse has it?

· Clean hoofs out daily

· Wash the frog with povidone-iodine scrub or antibacterial soap

· Apply an anti-thrush product or remedy

· Reapply according to the product instructions

· Keep your horse in dry living conditions until the infection has cleared

· If your horse has chronic thrush, add daily hoof supplement to your horse's diet

Favorite Anti-Thrush Products

This product isn’t labeled as an anti-thrush treatment, but this is definitely my go-to when it comes to treating my horses for thrush. The main ingredients are Isopropyl Alcohol (antibacterial & antimicrobial), Acriflavin (topical antiseptic), and Methyl Violet (Gentian Violet - anti-fungal). These ingredients are some of the primary ingredients in popular anti-thrush products but is in a quick and easy-to-use aerosol spray. I usually have to apply to the affected hooves every other day for about a week.

Thrush Buster® helps treat thrush and reduce the risk of re-infection. A single application is powerful enough to last up to eight days without re-application. Ingredients: water, isopropanel formalin, PVP, iodine complex and Gentian Violet.

Aerosol solution designed to eliminate thrush and white line disease. Made with tea tree oil to nourish and protect the hoof. Ingredients contain 5% chloroxylenol and 0.5% allantoin.

Purges bacteria, fungi and spores from deep cracks and crevices. Broad spectrum formula gets the job done fast, predictably, reliably and painlessly. Contains mineral oil, chlorhexidine, neem oil, zinc oxide, petrolatum, cetearyl alcohol, ceteareth 20, glycerine, colalipid ST and lavender essential oil.

Favorite Hoof Supplements

Farrier's Formula Double Strength is a pelleted hoof supplement that can be added as a top

dressing on the regular feed or given separately. It provides nutrients such as phospholipids, omega fatty acids, vitamins, minerals, and important amino acid “protein building blocks” for a healthy hoof and hair coat. These nutrients are provided at twice the concentration compared to original Farrier's Formula. Farrier’s Formula Double Strength supplies the nutrients required for building strong hoof capsule connective

tissue in the correct balance and ratios. It promotes strong and fast growth of the hoof wall, sole, frog, and heel. Farrier’s Formula Double Strength also promotes a glossy more deeply colored coat and strengthened connective tissues of the joints and ligaments.

When your horse’s feet could use some extra help, turn to the nutritional supplements recommended by top farriers. Trust Horseshoer’s Secret Pelleted Hoof Supplement original formula to provide key nutrition to help prevent cracked hooves and strengthen hoof walls. Formulated to provide optimum benefits for healthy hooves

  • Promotes healthy hoof growth

  • Highly palatable and easy-to-feed

  • Contains biotin, protein, calcium, phosphorus, copper, zinc, methionine, lysine, yeast culture and omega-3 and omega-6 fatty acids


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