Equine Thrush: Causes, Signs, Treatment and Prevention
- Grab the Reins Equestrian
- 1 day ago
- 6 min read
Thrush is one of the most common hoof problems seen in horses. While it often starts as a mild issue, it can become painful and damaging if left untreated. The good news is that thrush is usually straightforward to manage when it’s caught early and the right care is put in place.
This guide explains what equine thrush is, why it develops, how to recognise it, and what you can do to treat and prevent it.
Jump to:
2. Causes
3. Signs
4. Diagnosis
5. Treatment
6. Prevention
Medical disclaimer
The information provided in this article is intended for general educational purposes only. It is not a substitute for professional veterinary advice, diagnosis, or treatment.
Always seek the advice of a qualified veterinarian or farrier with any questions you may have regarding your horse’s health or a specific medical condition. Never disregard professional advice or delay seeking it because of information read here.
What is equine thrush?
Equine thrush is a bacterial infection of the frog, the soft, triangular structure on the underside of the hoof. It most commonly affects the grooves on either side of the frog and the central cleft.
The bacteria involved thrive in low-oxygen, damp, dirty environments, which is why thrush is often associated with muddy turnout, wet bedding, or poor hoof hygiene.
In early cases, thrush may only affect the surface of the frog. If allowed to progress, it can invade deeper tissues and lead to soreness or lameness.
What causes thrush?
Thrush usually develops when several risk factors combine. Common causes include:
Wet or muddy conditions
Prolonged exposure to mud, wet bedding, or manure creates ideal conditions for bacteria to grow.
Poor hoof hygiene
Infrequent hoof cleaning allows debris and bacteria to build up in the frog grooves.
Limited airflow to the hoof
Deep or narrow frog clefts, contracted heels, or poor hoof balance can reduce oxygen reaching the frog.
Long intervals between trims
Overgrown or unbalanced hooves can trap moisture and debris.
Limited movement
Horses standing in for long periods, particularly in wet conditions, may be more prone.
Signs of thrush to look out for
Thrush is often easy to identify once you know what to look — and smell — for.
Common signs include:
A strong, unpleasant odour when picking out the hooves
Black or dark discharge in the frog grooves
Soft, crumbly, or ragged frog tissue
Sensitivity or discomfort when the frog is cleaned
Deep or widening grooves in the frog
Not all horses with thrush will show lameness, especially in mild cases. However, more advanced infections can cause pain and affect soundness.
How is thrush diagnosed?
Thrush is usually diagnosed through a visual and physical examination of the hoof. The appearance of the frog combined with the characteristic smell is often enough to confirm it.
In more severe cases, or where the horse is lame, a vet or farrier may assess how deeply the infection has spread and whether other hoof conditions are present.
Treating equine thrush
Treatment focuses on removing the conditions that allow bacteria to thrive and supporting healthy frog tissue.
General treatment principles include:
Clean and dry the hooves daily
Pick out hooves thoroughly and remove all dirt and debris.
Expose the frog to air
Loose or diseased tissue may need to be carefully removed by a farrier to allow oxygen to reach affected areas.
Use appropriate topical treatments
Mild antiseptic solutions are commonly used. Avoid overly harsh or caustic products that may damage healthy tissue.
Improve the horse’s environment
Reduce exposure to mud, wet bedding, and manure wherever possible.
If thrush is severe, persistent, or causing pain or lameness, advice should be sought from a qualified vet or farrier.
Preventing thrush
Good management and routine hoof care are the most effective ways to prevent thrush.
Helpful prevention measures include:
Picking out hooves daily
Keeping bedding and standing areas clean and dry
Managing muddy turnout when possible
Maintaining a regular trimming or shoeing schedule
Encouraging movement and turnout
Supporting overall hoof health with balanced nutrition
Thrush is especially common during wet seasons, so increased vigilance at these times is important.
When should you be concerned?
You should contact your vet or farrier if:
The frog becomes very painful or starts to bleed
The horse develops lameness
The infection does not improve despite good care
You are unsure whether the problem is thrush or another hoof condition
Early intervention can help prevent long-term hoof damage.
Key takeaway
Thrush is a common but manageable hoof condition. With regular hoof care, clean conditions, and early treatment, most cases resolve quickly. Paying attention to your horse’s feet every day is one of the simplest and most effective ways to protect long-term soundness.
Medical disclaimer
The information provided in this article is intended for general educational purposes only. It is not a substitute for professional veterinary advice, diagnosis, or treatment.
Always seek the advice of a qualified veterinarian or farrier with any questions you may have regarding your horse’s health or a specific medical condition. Never disregard professional advice or delay seeking it because of information read here.
Frequently Asked Questions about Equine Thrush
Can thrush cause lameness?
Yes, thrush can cause lameness if it becomes severe or is left untreated. In early stages, many horses show no obvious discomfort. However, if the infection spreads into deeper, sensitive tissues of the hoof, it can become painful and may affect soundness. Any signs of lameness should be assessed by a vet or farrier.
How long does thrush take to heal?
Mild cases of thrush can begin to improve within a few days to a couple of weeks once proper cleaning, treatment, and environmental management are in place. More advanced cases may take longer and require professional input. Consistency with hoof care is key.
Is thrush contagious between horses?
Thrush itself is not considered contagious, but the conditions that allow it to develop can affect multiple horses. Wet, dirty environments and poor hygiene can lead to several horses on the same yard developing thrush at the same time.
Can thrush come back?
Yes. Thrush can recur, especially during wet weather or if management factors such as hygiene, turnout conditions, or trimming schedules are not addressed. Regular hoof care and early intervention greatly reduce the risk of repeat infections.
Should I call a vet or a farrier for thrush?
For mild cases, a farrier can often help by trimming away affected tissue and advising on hoof balance. If thrush is severe, painful, not improving, or causing lameness, a vet should be consulted. In many cases, vets and farriers work together to manage more advanced infections.
Can thrush affect shod and barefoot horses?
Yes. Thrush can affect both shod and barefoot horses. Barefoot horses may develop thrush in deep frog clefts, while shod horses may be at risk if moisture and debris are trapped around the frog or heels.
Is thrush more common in winter?
Thrush is more common during wet, muddy seasons, particularly autumn and winter, when horses spend more time standing in damp conditions. Increased vigilance during these periods is important.
Can diet affect thrush?
Diet does not directly cause thrush, but overall hoof health is influenced by nutrition. A balanced diet that supports hoof strength and horn quality can help the frog resist infection and recover more effectively.
What’s the difference between thrush and other hoof infections?
Thrush mainly affects the frog and its grooves and is usually identified by a strong odour and black discharge. Other hoof conditions, such as white line disease or abscesses, affect different structures of the hoof and may require different treatment. If you’re unsure, seek professional advice.
When should I be worried about thrush?
You should seek professional advice if:
The frog becomes very painful or starts to bleed
Your horse becomes lame
The infection does not improve with good care
You are unsure whether the issue is thrush or another hoof condition
Early assessment can prevent long-term damage.
References & further reading
Merck Veterinary Manual – Disorders of the Foot in Horses (Thrush)
British Horse Society – Thrush in Horses
Michigan State University Extension – Preventing and Treating Thrush in Horses
Edwards et al., Veterinary Microbiology (2013): Association of Fusobacterium necrophorum with equine hoof thrush
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