Types of Hoof Infections in Horses | Causes and Treatment

Hoof infections in horses run from the trivial — a damp, smelly frog after a wet week — to the limb-threatening, with internal abscesses, advanced canker and undermined laminae all sitting at the serious end of the spectrum. The vast majority are preventable. Most are also missed for too long, because owners either fail to pick the foot up or fail to recognise what they are looking at.

This guide is the complete UK and South African reference for the four common hoof infections every horse owner needs to recognise: thrush, white line disease (seedy toe), canker and hoof abscesses. Each section covers what the infection is, what causes it, how to spot it, what the vet or farrier will do, and how to prevent it coming back.

Anatomy of the Hoof — A Quick Refresher

Hoof infections almost always live in three places: the frog, the white line, or the laminae beneath the sole. Knowing the geography of the foot makes the rest of this article make sense.

• Hoof wall — the hard, protective outer cylinder of horn that bears most of the horse’s weight.
• Sole — the slightly concave, weight-distributing underside of the hoof.
• Frog — the rubbery, V-shaped pad in the rear of the sole that absorbs concussion.
• Frog sulci — the central and lateral grooves that flank the frog. Thrush lives here.
• White line — the visible junction between the inner hoof wall and the sole. White line disease lives here.
• Heel bulbs — the soft, paired prominences at the back of the foot. Canker often starts here.
• Laminae — the velcro-like tissues that bond the inner hoof wall to the third phalanx (pedal bone). Subsolar abscesses sit beneath these. If you want the deeper anatomy, our guide to the coffin joint explains what sits inside the hoof capsule.

Thrush in Horses

Thrush is the most common hoof infection in horses and the easiest to spot if you pick out the foot regularly. It is a bacterial infection of the frog and the surrounding sulci, primarily caused by Fusobacterium necrophorum, an anaerobic bacterium that thrives in the warm, wet, oxygen-poor environment of a deep frog cleft packed with mud, manure and bedding.

Signs of Thrush

• A foul, distinctive black-pudding smell from the foot — often noticeable before any visual change.
• A black, oily or tar-like discharge in the central and lateral sulci of the frog.
• The frog itself looks ragged, soft and crumbly rather than firm and rubbery.
• Deepening of the central sulcus into a narrow, painful split.
• Tenderness when picking out the foot, particularly in the central sulcus.
• In advanced cases, lameness as the infection invades sensitive deeper tissues including the digital cushion and heel bulbs.

Causes and Risk Factors

• Wet, dirty bedding — particularly deep-litter beds that are not properly skipped out daily.
• Permanent muddy turnout — the classic British winter risk factor.
• Infrequent hoof picking — bacteria thrive in packed-in detritus.
• Conformation — horses with naturally upright, club feet or contracted heels have deeper, narrower sulci that hold debris and exclude oxygen.
• Poor or overdue farriery — long heels, low frog pressure and overgrown bars all contribute.
• Lack of exercise — movement increases blood supply to the foot and naturally cleanses the frog. A horse in extended box rest is at higher risk.

Treatment

1. Pick the foot out twice daily and scrub. Use a hoof pick, then a stiff brush, and finally a wet brush with antibacterial wash to clean both sulci to the depth of the cleft.
2. Trim ragged frog tissue. Speak to your farrier — flaps of dead frog hold infection and need to come off so oxygen can reach the underlying tissue.
3. Apply a topical antibacterial. Over-the-counter options include diluted iodine (Betadine), copper sulphate solution, dilute hydrogen peroxide, or branded products such as Hoof Stuff (Red Horse Products), Field Paste, or Cornucresine. The British Horse Society recommends a clean, iodine-based regimen for early thrush.
4. Keep the horse on dry, clean bedding. Wood-based bedding (BedMax-type shavings) or cardboard wicks moisture better than straw alone for affected horses.
5. Daily exercise where possible. Movement is therapy. A horse on box rest with thrush needs hand-walking on hard, dry standing.
6. Refer to the vet if there is lameness, deep central-sulcus splits, fever, swelling above the heel, or the infection has not improved within ten days of conscientious care.

Most cases of mild thrush respond to two to three weeks of daily care. Deep central-sulcus thrush, where the infection has burrowed into the soft tissue between the heel bulbs, is more stubborn and often needs the farrier and vet working together. We have a deeper structured medical reference on thrush in horses, plus a practical, step-by-step guide to treating hoof thrush if you want full clinical detail.

White Line Disease in Horses (Seedy Toe)

White line disease — known in the UK and SA traditionally as seedy toe — is an infection that invades the white line, the layer of horn that joins the inner hoof wall to the sole. The infection is polymicrobial: a mix of bacteria and fungi exploiting a defect in the white line and gradually undermining the hoof wall from the inside out.

Signs of White Line Disease

• A crumbly, powdery, chalk-like white material visible at the white line when the foot is trimmed or picked out.
• A separation or “hollow” along the white line at the toe or quarters that you can probe with a hoof pick.
• In advanced cases, a visible cavity or ridge appearing on the outer hoof wall above the white-line defect.
• A change in the angle of the hoof wall as the infection undermines support.
• Lameness in advanced cases when rotation or sinking of the pedal bone occurs.

Causes and Risk Factors

• Damage or weakness in the white line — created by chronic laminitis, hoof wall cracks, an old abscess track, poor shoeing or repeated wet/dry cycling of the horn.
• Persistent wet conditions — same enabling environment as thrush.
• Long shoeing intervals — long toes lever the white line apart at every step.
• Previous laminitis — a horse that has had laminitis carries permanent weakness in the lamina-sole junction and is significantly predisposed.

Treatment

White line disease is principally a farriery problem. The vet may be involved if the disease is extensive or if pedal bone changes are suspected.

1. Resection. The farrier removes the diseased horn — sometimes a small flap, sometimes a much larger window in the hoof wall — to expose the infected area to air. Anaerobic infection cannot survive in oxygen.
2. Aggressive cleaning. The cavity is scrubbed daily with antiseptic — diluted iodine or chlorhexidine — and packed with an antibacterial paste. Specialist farriers often use copper-sulphate-based packings, formaldehyde-based treatments, or a clay-and-iodine mix.
3. Mechanical support. A bar shoe, glue-on shoe or hoof boot stabilises the hoof while the wall regrows. In severe cases the entire toe may need to be resected and supported.
4. Long-term hoof regrowth. A complete hoof wall regrows in nine to twelve months. The horse needs scrupulous care, regular trimming, and dry footing throughout.
5. Address the underlying cause — particularly any history of laminitis. A horse that develops white line disease without explanation should have a metabolic workup (Cushing’s disease, equine metabolic syndrome) considered.

Most cases caught early respond well. Advanced cases with significant pedal bone involvement can be career-ending and occasionally life-threatening. The deeper structured medical reference is on the white line disease (seedy toe) page, and we cover the day-to-day management in our white line disease guide.

Canker in Horses

Canker is a chronic, proliferative bacterial infection of the frog, sulci and heel bulbs that causes the affected tissue to become soft, fleshy, foul-smelling and ulcerated. Unlike thrush, which destroys frog tissue, canker produces an overgrowth of abnormal, unhealthy tissue that bleeds easily and resists ordinary treatment. It is far less common than thrush but considerably more serious.

Signs of Canker

• An offensive, distinctive odour — different from thrush, often described as “rotting fish” or “foul cheese.”
• A soft, white-yellow, cottage-cheese-like growth in the frog area or heel bulbs.
• The affected tissue bleeds readily on contact and is sensitive to pressure.
• The infection may extend up the back of the heel bulbs and into the soft tissues of the pastern.
• One or all four feet may be involved — multiple-foot canker is unfortunately common.
• Lameness varies and is not always severe in early cases, which is partly why canker is often diagnosed late.

Causes and Risk Factors

The exact cause of canker is still debated, but the disease is associated with anaerobic bacteria including Fusobacterium necrophorum and various spirochaetes. Risk factors include:

• Persistently wet, contaminated environments — the heaviest-affected populations in the UK are draught and feathered breeds living in damp standing.
• Heavy feathered breeds — Shire, Clydesdale, Gypsy Cob, Friesian. The thick feather traps moisture against the heel bulbs and pastern.
• Compromised immunity or poor general condition.
• Pre-existing thrush or hoof injury that allows bacterial entry.

Treatment

Canker is a vet-and-farrier job from the start. Casual home treatment will not resolve it.

1. Surgical debridement under sedation or general anaesthesia — every speck of abnormal tissue must be removed. Often performed in stages over multiple visits.
2. Topical treatment after debridement — metronidazole paste applied directly to the wound is now the standard first-line therapy in many UK referral hospitals, with daily bandage changes for several weeks.
3. Cryotherapy in selected cases.
4. Systemic antibiotics in some cases, though most modern protocols emphasise topical treatment.
5. Strict environmental change — clean, dry standing, daily bandage changes, frequent wound monitoring.
6. Long convalescence — six weeks of intensive treatment is typical. Recurrence is unfortunately common, particularly if the underlying environment is not corrected.

Outcomes have improved considerably with modern topical metronidazole protocols, but canker remains a serious diagnosis. The deeper medical reference is on our equine canker page.

Hoof Abscesses

A hoof abscess is a localised pocket of infection beneath the sole or hoof wall, almost always the consequence of bacteria entering through a small defect in the white line, sole or heel and being trapped between the rigid hoof wall and the underlying sensitive tissue. It is the single most common cause of acute, severe lameness in horses on UK and SA yards — a horse goes from sound on Monday evening to non-weight-bearing on Tuesday morning, and the cause is almost always an abscess.

Signs of a Hoof Abscess

• Sudden, severe lameness — frequently grade 4 of 5, with the horse refusing to bear weight. This dramatic onset is the classic signature.
• A bounding digital pulse on the affected foot.
• Heat in the hoof wall and the coronary band.
• Localised pain on hoof testers applied by the farrier or vet — pain in one specific spot identifies the location of the abscess.
• Sometimes a visible black mark or track in the sole or white line.
• Eventual rupture — most untreated abscesses rupture either at the sole or, more commonly, at the coronary band as the infection tracks up the hoof wall.

Causes

• A small puncture wound — a stone, a stub of wire, a stable nail.
• A bruise that has subsequently become infected.
• A sub-clinical white line tract giving bacteria access.
• Sudden ground changes — rock-hard ground after dry weather, or wet ground softening the sole.
• Hoof imbalance and shoeing problems that produce localised pressure.

Treatment

1. Establish drainage — the priority. The vet or farrier locates the abscess with hoof testers and pares away enough sole or wall to release the pus. The horse usually shows immediate, dramatic relief once drainage is achieved.
2. Poultice the foot — Animalintex or a clay-based equine poultice, changed once or twice daily, draws remaining pus out and keeps the abscess track open. Continue until the discharge is clean.
3. Tetanus protection — every abscess is a potential tetanus source. Ensure cover is current.
4. Hoof boot or surgical bandage protects the foot during convalescence.
5. Antibiotics are usually not indicated in an uncomplicated abscess once drainage is achieved, and may delay rupture by suppressing the body’s response. They are reserved for complicated cases — pedal bone involvement, deep digital flexor tendon sheath infection, or a horse that is unwell.
6. Return to work within a fortnight in most uncomplicated cases.

The greatest risk in abscesses is treating them as a soft-tissue lameness that will pass with rest. They will not. They need draining. A foot that has been lame for more than 48 hours without improvement should have hoof testers applied by a vet or farrier on day three at the latest. For a full clinical breakdown, see our hoof abscess reference, along with the MSD Veterinary Manual and World Horse Welfare guidance.

How to Tell Them Apart

The four common hoof infections each have a different signature.

If a foot looks or smells wrong but the horse is sound, you usually have time to treat it carefully. If a horse is suddenly, severely lame, you have an abscess until proven otherwise — call the vet or farrier today, not in three days.

Prevention: A Daily Hoof Routine

Every hoof infection in this guide is dramatically less common in horses with consistent daily hoof care.

1. Pick out all four feet twice daily. Once before work and once at evening checks. Use a stiff brush to remove the last of the debris from the sulci.
2. Inspect each foot. Look at the frog, the white line, the sole, the heel bulbs and the coronary band. Smell the foot. Note any change.
3. Keep bedding clean. Skip out two or three times a day. Replace damp banking. Choose a wicking bedding (shavings, cardboard, hemp) over straw alone if your yard is wet.
4. Manage turnout. Rotate gateways, use surfaced gateways or rubber matting in heavy traffic areas, and let standing water drain.
5. Six-week farrier cycles. Five weeks if your horse is on heavy work or has previous problems.
6. Address feathered breeds carefully. Feather looks beautiful but holds moisture against the heel bulbs. Wash, dry thoroughly and inspect daily in winter.
7. Ride forward. A horse in regular work has better hoof circulation, stronger frogs and more naturally cleansed feet than a horse standing in a box.
8. Address laminitis history. A horse with previous laminitis needs ongoing metabolic management and tighter hoof routines.

When to Call the Farrier vs the Vet

Call the farrier for: routine thrush, white line disease, suspected hoof imbalance contributing to recurrent infections, lost or twisted shoes, or any chronic hoof problem developing over weeks rather than days.

Call the vet for: any sudden severe lameness (suspected abscess), suspected canker, infections involving the coronary band, fever or systemic illness, lameness lasting more than 48 hours without explanation, deep central-sulcus thrush with lameness, or any wound that exposes deeper tissues.

The farrier and vet often need to work together on the more serious infections. Set the expectation early that you may need both — a good vet practice and a good farrier already know each other and will coordinate care.

Breeds and Conformations Most at Risk

• Heavy, feathered breeds — Shire, Clydesdale, Gypsy Cob, Friesian — at greater risk of canker, thrush and feather-related skin infections such as mud fever (pastern dermatitis).
• Native ponies on permanent grass — particularly Welsh, New Forest and Dartmoor — with chronic thrush from constant wet turnout.
• Horses with upright/club feet — deeper sulci and contracted heels predispose to thrush and recurrent abscesses.
• Horses with previous laminitis — greatly increased risk of white line disease.
• Cushing’s (PPID) and EMS horses — compromised immunity and abnormal hoof horn quality.
• Older horses on box rest — reduced movement, reduced hoof circulation, increased risk of thrush and abscess.

UK and SA Climate Considerations

The UK climate presents the classic high-risk environment: long wet winters, persistent muddy gateways, and frequent freeze-thaw cycles. Hoof infections cluster from October to April. The risk peaks in late winter when standing has been wet for months and horses spend more time stabled on potentially under-skipped beds.

The South African climate presents a different pattern. The summer rainfall regions (Highveld, KZN) see infection clusters in November to March, when warm, wet conditions favour bacterial growth. The Western Cape’s wet winter brings a UK-style problem from May to August. Year-round dry regions (Karoo, Northern Cape) see fewer hoof infections but more sole bruising and abscess from rock-hard ground — different problem, same vigilance required.

Frequently Asked Questions

How do I treat thrush in my horse?

Pick the foot out twice daily, scrub the frog and sulci clean with a stiff brush and dilute iodine or chlorhexidine, ask the farrier to trim away ragged frog tissue, apply an antibacterial topical such as iodine, copper sulphate or a branded equine preparation, and keep the horse on dry, clean bedding. Most cases improve in two to three weeks. If they do not, or if there is lameness, ask the vet.

Does thrush go away on its own?

Mild thrush sometimes resolves when conditions improve, but assuming it will is a gamble. Untreated thrush can deepen into the sensitive structures of the frog, cause central-sulcus disease and lead to lameness. Active treatment is always preferable to waiting it out.

What does white line disease look like?

It looks like crumbly, powdery, chalk-like material along the white line at the bottom of the foot, often with a probing depth that increases the more you investigate. In advanced cases there is a hollow ridge or cavity visible on the outer hoof wall above the diseased area.

Can canker be cured?

Yes, in most cases, but treatment is intensive — surgical debridement, topical metronidazole and rigorous bandage management over six weeks or more, with strict environmental control. Recurrence is common if the underlying environment is not corrected. Get a referral to an experienced equine surgical team early if canker is suspected.

How long does a hoof abscess take to heal?

Once drainage is achieved, most uncomplicated abscesses heal in seven to ten days. Lameness usually resolves within 24 to 48 hours of drainage. Abscesses that rupture at the coronary band can leave a track that takes longer to seal and occasionally a permanent ridge in the regrowing hoof wall.

Should I use antibiotics for a hoof abscess?

Usually no. The treatment for an abscess is drainage, not antibiotics. Antibiotics may suppress the body’s response, delay rupture, and prolong the problem. The vet may use them in complicated cases — pedal bone involvement, joint infection, severe systemic illness — but routine, uncomplicated abscesses are managed by drainage and poulticing alone.

Why do my horse’s feet keep getting infected?

Recurrent hoof infection is almost always a management or mechanical problem. Look at: bedding hygiene, turnout standing, hoof picking frequency, farrier cycle, hoof balance, history of laminitis, and metabolic disease. Recurrence is information — it means a root cause has not been addressed.

Can I use apple cider vinegar for thrush?

Apple cider vinegar is mildly acidic and has been used as a folk remedy. Mild cases of early thrush sometimes respond, but it is far less reliable than diluted iodine, chlorhexidine or a dedicated equine product. For deep, established or central-sulcus thrush, use a vet-recommended preparation.

For deeper structured medical detail on each condition, see our thrush in horses, white line disease, equine canker and hoof abscess reference pages. The British Horse Society hoof care guide and its dedicated hoof abscess guidance are the authoritative UK welfare references. Your vet and farrier remain the central decision-makers on individual cases.