Low severity

Thrush

Thrush is an infection of the frog — the V-shaped, rubbery structure on the sole of the hoof. It thrives when feet stay wet, packed with mud or manure, or are left unpicked. Most cases are a hygiene and farriery problem. A photograph cannot diagnose thrush, and the app scan is a first look at the hoof, not a verdict that your horse has thrush.

Symptoms to watch for

Black, tar-like discharge in the grooves (sulci) beside or in the centre of the frog

A strong, foul odour when the foot is picked out

A frog that looks ragged, pitted, or softer than usual

Sensitivity when cleaning deep into the sulci in more advanced cases

Lameness only when infection reaches sensitive tissue — many horses stay sound

Common causes

Prolonged wet or muddy standing — paddocks, gateways, and soiled bedding
Feet left unpicked, so packed mud and manure sit in the frog sulci
A contracted or deep-sulcus frog that traps debris
Infrequent farrier care leaving overgrown or necrotic frog horn
Poor stable hygiene and constantly damp floors
Opportunistic bacteria (often including Fusobacterium necrophorum) in anaerobic, dirty sulci

Prevention

Pick out all four feet every day, including the collateral and central sulci of the frog
Provide dry standing — woodchips at gates, well-drained turnout, and clean bedding
Keep stables mucked out so horses are not standing in wet manure
Schedule regular farrier visits so the frog is trimmed and the foot can self-clean
After wet work or muddy turnout, pick out the feet and let them dry rather than leaving them packed
Do not treat a photo or a scan result as a diagnosis

What to do

1
Pick the foot thoroughly and look at the frog in good light — note odour, colour, and how deep the sulci are.
2
Move the horse onto clean, dry standing. Thrush will not resolve while the foot stays wet and packed.
3
Ask your farrier to trim loose or necrotic frog horn so the sulci can be cleaned and aired.
4
After trimming, clean the sulci daily and apply a product your farrier or vet recommends for thrush (commonly iodine-based or a commercial frog treatment).
5
Keep the treated foot dry between applications. Avoid packing the sulci with wet mud or heavy grease that seals in moisture.
6
If the horse is lame, the frog is painful to firm pressure, or the infection looks deep, stop home treatment and call the vet — do not keep digging.

When to call the vet

Pick up the phone if…

Call the vet if the horse is lame, if the frog is painful or bleeding, if you can see deep tissue or pus, or if daily cleaning and dry standing have not improved the smell and discharge within one to two weeks. Thrush can be confused with a puncture, canker, or white line disease — those need a vet, not a photo guess.