Thrush in horses: recognising and treating it

What exactly is thrush?

Thrush develops when bacteria — primarily Fusobacterium necrophorum — accumulate in the grooves of the frog. The soft hoof tissue becomes affected and literally begins to rot. You can recognise it by black, slimy material in the central and lateral frog grooves, a penetrating sour smell, and a soft or hollowed-out frog. In severe cases the damage extends into the deeper layers of the frog, causing pain and lameness. Because the frog plays a shock-absorbing and circulation-promoting role, a healthy frog is essential for your horse's wellbeing.

Causes: not just mud and moisture

Wet and unhygienic conditions are the main risk factors, but thrush has multiple causes:

• Standing on wet or dirty surfaces for extended periods (mud, manure, wet bedding)
• Insufficient movement, meaning the frog is not adequately stimulated
• Too little or irregular hoof care — pick out hooves at least once a week on average
• Narrow, deep frog grooves that trap dirt
• Enclosed stabling with poor ventilation

How to recognise thrush early

Early detection prevents a mild condition from developing into a serious problem. During daily hoof picking, watch out for these signs:

• Black or dark grey slimy material in the frog grooves
• A penetrating, sour or rotten smell when picking out the hoof
• A soft, crumbly or hollowed-out frog
• The horse pulling its hoof away when the frog grooves are touched
• Visible discolouration or a depression in the centre of the frog

Treatment step by step

Mild cases of thrush can be treated yourself. Clean the hoof thoroughly with a hoof pick and remove all loose or necrotic tissue — an old toothbrush can be useful for this. Rinse the grooves with water and pat dry. Then apply a treatment product such as diluted chlorhexidine (2%), iodine solution, or a ready-to-use thrush spray. Repeat this daily until the frog is dry, firm, and odour-free — allow 7 to 14 days for a mild case. In the meantime, ensure a dry, clean stable and as much movement as possible. In cases of deep tissue involvement or lameness, always consult a farrier or vet for professional debridement and treatment.

Prevention is better than cure

A consistent routine is the best protection against thrush. Practical measures that genuinely work:

• Pick out hooves at least once a day, including in the field
• Provide a dry lying area of at least 10–12 m² per horse
• Change bedding regularly and remove manure immediately
• Allow your horse at least 2 hours of movement per day on dry ground
• Schedule a farrier visit every 6–8 weeks and ask for attention to frog condition

EquiSight helps you keep track

Consistency is everything when it comes to hoof care. In EquiSight's horse dossier you can record hoof treatments, farrier visits, and notable findings with a date and photo. This gives you an instant overview of whether the frog condition is improving or recurring. Use the calendar to set reminders for daily checks or the next farrier visit. Not sure about what you're seeing? Ask EquiCoach — the built-in intelligence helps you determine whether you're dealing with thrush or another hoof problem, and provides initial advice on the next step.