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Contagious ovine digital dermatitis
Contagious digital dermatitis is a particularly painful sheep foot disease and particularly discouraging for the breeder, because it behaves like no other. It is caused by spiral-shaped bacteria, called treponemes, which settle in the skin...
What is it?
Contagious digital dermatitis is a particularly painful sheep foot disease and particularly discouraging for the breeder, because it behaves like no other.
It is caused by spiral-shaped bacteria, called treponemes, which settle in the skin above the hoof and destroy the horn attachment.
Its distinctive sign is the sense of progression. Footrot starts from the skin between the hooves and lifts the horn from the heel towards the claw. Here, it's the opposite: the lesion begins at the labrum, this strip of skin just above the horn, in the form of a red and bleeding ulceration, then goes down and peels off the entire wall of the hoof from the top.
Key point
Do not trim affected feet: trimming clearly aggravates this disease and spreads it throughout the herd. If a flock does not respond to usual treatments for footrot, have the feet examined by the veterinarian before proceeding.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Severe lameness, often brutal and much more painful than that of foot rot: the animal no longer puts its foot down, refuses to move, moves on its knees.
Only one foot is most often affected at first, sometimes two.
Characteristic lesion on the labrum, just above the horn: bright red ulceration, moist, bleeding, very painful at the slightest contact.
Progression from top to bottom: the wall of the claw comes off from the bead, and the horn can be lifted downwards.
In advanced cases, complete loss of the horn box: the claw becomes detached, the animal walks on the raw flesh.
Unpleasant odor, different from that of footrot.
Skin between the hooves often normal or little affected at first, which is an important clue to distinguish it from foot rot.
Rapid weight loss, animals which no longer follow, which remain lying down and no longer eat properly.
Lameness that does not respond to footbaths and usual treatments for foot rot, and which worsens after trimming.
In an affected herd, several animals affected successively, with a progression that is worrying.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Spiral-shaped bacteria, treponemes, are involved in the lesions. They settle in the skin of the labrum and gradually destroy the attachment of the horn.
They take advantage of any pre-existing foot damage: scald, foot rot, injury, skin softened by humidity.
Prolonged humidity and contaminated environments favor their survival and transmission.
Trimming aggravates the lesions: by opening the horn and exposing the flesh, it gives bacteria direct access to the tissues. This is a counterintuitive but well-established point, and it explains many treatment failures.
These bacteria survive in litter, mud and on trimming equipment.
Local treatments alone do not reach the bacteria deep in the skin, which explains the poor response to footbaths.
Purchasing animals without quarantine or foot examination: this is the main route of entry.
Presence of foot rot or scald in the herd, which weakens the feet.
Damp and muddy environments, soggy litter, overdensity.
Systematic trimming of the herd with non-disinfected equipment between animals.
Aggressive trimming of affected feet, which aggravates and spreads the disease.
Animal groups, fairs, common pastures, ram loans.
Absence of isolation of lame animals, which contaminate passage areas.
Transmission
It is a contagious disease, which is transmitted from one animal to another through soiled soil, litter, mud and areas of forced passage.
Trimming equipment not disinfected between animals is a recognized vector: trimming several feet with the same pliers without disinfection spreads the disease throughout the herd.
The introduction of purchased animals is the main route of entry onto a farm unharmed. As the beginning lesions are discreet, an animal may appear healthy upon purchase.
Wet and muddy areas, corridors and areas around watering troughs concentrate contamination.
There is no risk for humans.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The examination of the foot by the veterinarian is essential, because it is the diagnosis which requires the treatment, and a foot rot treatment applied here will do nothing.
The veterinarian looks for the starting point of the lesion: at the bead, above the horn, and not between the hooves. This single element is very orienting.
He checks the direction of the separation: from top to bottom in this disease, from the heel towards the pinch in foot rot.
He examines several animals in the group, including those with little lameness, to identify beginning lesions and assess the extent of the problem.
It removes foot rot, foot abscess, scald, laminitis and foreign bodies.
Laboratory samples may be taken in doubtful situations or when a herd does not respond to any treatment.
A complete breeding visit, with examination of the feet on a representative sample, is the best investment in a herd where lameness is resistant: it avoids months of ineffective treatments.
Treatment
Treatment is mainly based on an antibiotic administered systemically, prescribed by the veterinarian. This is what most differentiates this disease from foot rot, where local treatment and footbaths play a central role.
The choice of the molecule, the route and the duration are entirely up to the veterinarian, and the treatment must be carried out until its end: early cessation leads to relapses.
Local treatment can be combined, on prescription, but it is not enough alone.
An anti-inflammatory relieves pain which is very significant here, and allows the animal to start moving and eating again.
Do not trim affected feet. This is the most important and counterintuitive instruction in this sheet: trimming opens the horn, exposes the flesh and frankly aggravates the lesions. If minimal trimming is necessary, it is decided and carried out by the veterinarian.
Isolate affected animals in a clean, dry area, away from areas where the herd passes through, for the duration of treatment.
Systematically disinfect trimming equipment between each animal, including healthy animals.
Footbaths give disappointing results in this disease, unlike foot rot: do not count on them and do not insist to the detriment of good treatment.
Ask the veterinarian about the withdrawal periods for meat and milk products used and respect them.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Quarantine of purchased animals is the number one measure: isolation away from the herd, examination of the feet of each animal by the veterinarian, and integration only after inspection.
Avoid lending rams and grouping animals of different origins.
Disinfect trimming equipment between each animal, without exception: it is a recognized vector.
Immediately isolate any lame animal, in a clean area, rather than allowing it to circulate and contaminate the corridors.
Keep feet dry: drainage, stoning around water troughs, abundant and renewed litter.
Master the scald and footrot, which prepare the ground.
Monitor the herd and respond to the first lameness that is not behaving as usual, rather than waiting until several animals are affected.
In an affected herd, establish a written plan with the veterinarian: identification of treated animals, isolation, schedule, and decision on animals to be culled.
Cull animals which relapse despite well-conducted treatments: they maintain the disease in the herd.
Vaccination
There is no vaccine against this disease.
The vaccines available in certain countries against foot rot do not protect against it: this is a confusion to be avoided, because it leads to believing the herd is protected when it is not. Talk to your veterinarian before embarking on a foot vaccination program.
Possible complications
Complete loss of the horn box, with an animal walking on raw flesh: extreme pain and very long convalescence.
Permanent deformation of the regrown hoof, with chronic lameness.
Involvement of the joint and underlying bone in deep forms.
Severe and rapid weight loss, drop in fertility and production.
Animals lying down permanently, with bedsores and myiasis in the hot season.
Gradual spread to the entire herd if the affected animals are not isolated and if the trimming equipment is not disinfected.
Considerable cost in treatments, time and culled animals.
When to see a veterinarian
A limp is significantly more painful than usual and the animal no longer puts its foot down at all.
A red, bleeding lesion appears just above the horn, at the labrum.
The horn comes off from the top, or a claw comes off completely.
The lameness of your herd does not respond to footbaths or the usual treatments for foot rot: have the feet examined, it may be another disease.
The lameness gets worse after trimming.
Several animals are affected successively despite your efforts.
You have just purchased animals and unusual lameness appears: call quickly, the origin is probably there.
Prognosis
Good when the diagnosis is made early and the general treatment is carried out correctly and to the end: the lesions heal and the hoof grows back.
Reserved for advanced forms with loss of the horn box: regrowth takes months and the claw often remains deformed.
Bad when the joint is affected or when the animal relapses despite well-conducted treatments.
At the herd level, control requires rigor and time: quarantine, isolation of lame people, disinfection of equipment and culling of chronic cases. The herds which apply this plan survive, those which are satisfied with footbaths become exhausted.
Frequently asked questions
How to distinguish it from footrot?
By the starting point and the direction of progression. Footrot begins between the hooves and lifts the horn from the heel towards the claw. This begins at the bead, just above the horn, in the form of a bleeding red wound, and peels off the wall from top to bottom. It is also much more painful. The veterinarian must confirm, because the treatments are very different.
Why am I told not to parry?
Because trimming frankly aggravates this disease: it opens the horn, exposes the flesh and gives bacteria direct access to the tissues. This is exactly the opposite of the usual reflex when faced with a diseased foot, and this is why so many herds get worse despite treatment. If trimming is necessary, it is decided by the veterinarian.
My footbaths don't work, what should I do?
This is a strong signal. This disease responds poorly to foot baths, unlike foot rot, and requires general treatment prescribed by the veterinarian. A herd whose lameness resists everything should be examined foot by foot before continuing to spend on ineffective footbaths.
Will a completely detached hoof grow back?
Yes, the horn grows back, but it takes many months and the animal suffers a lot during this time. The reformed hoof often remains deformed. This is a situation that requires veterinary treatment, deep litter, anti-inflammatory medication and real thought about the animal's future.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 11 August 2026
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