Contagious Ovine Digital Dermatitis in Sheep: Severe Lameness and Hoof Disease

Contagious ovine digital dermatitis, usually called CODD, is a severe infectious disease of the feet in sheep. It causes marked pain and lameness, and it is considered an important welfare problem where it occurs. Unlike routine overgrowth or mild hoof irritation, CODD typically affects the skin at the coronary band first, then damages the hoof capsule as the disease progresses.

This condition is different from classic footrot, although the two can overlap. Research suggests CODD is strongly associated with several Treponema bacteria, and many affected sheep also have interdigital dermatitis or footrot organisms present at the same time. In practical terms, that means a sheep may not have one tidy diagnosis. Your vet may be managing a combination of infectious hoof diseases at once.

For pet parents and flock managers, the biggest concern is pain. Sheep with CODD may kneel to graze, lag behind, lose body condition, or spend more time lying down. In advanced cases, the hoof horn can separate from the underlying tissue, which is dramatic to see and very uncomfortable for the animal.

Because CODD is contagious and can spread within a group, one lame sheep should never be ignored. Early recognition gives your vet more treatment options and may reduce how many other sheep become affected.

CODD is considered a multibacterial infectious hoof disease. Studies have repeatedly linked it to digital dermatitis-associated Treponema species, and lesions often also contain Dichelobacter nodosus, the main bacterium involved in footrot, plus other bacteria such as Fusobacterium necrophorum. This helps explain why CODD can look similar to, or develop after, interdigital dermatitis and footrot.

The disease usually spreads through contact with infected sheep, contaminated ground, and handling areas where feet stay wet and dirty. Moist conditions soften the skin and hoof horn, making it easier for bacteria to invade. Overstocking, muddy bedding, poor drainage, and delayed treatment of lame sheep can all increase risk.

Research suggests some CODD lesions develop after earlier foot damage or infection, especially interdigital dermatitis or footrot. In other words, irritated or diseased feet may create an opening for more aggressive infection at the coronary band. That is one reason flock-level hoof health matters even when only a few sheep look severely affected.

There is also concern about transmission dynamics between sheep and cattle digital dermatitis organisms in some settings, so your vet may ask about mixed-species housing, shared pastures, and biosecurity practices. Even when the exact source is unclear, the practical takeaway is the same: isolate lame sheep early and address environmental risk factors.

Your vet usually starts with a hands-on foot exam and a careful history. The location of the lesion matters. CODD often begins at the coronary band and progresses downward, while classic footrot more often starts in the interdigital skin and under-runs the horn. Because these diseases can overlap, your vet will look for signs of both.

Diagnosis is often clinical, meaning it is based on what the lesions look like and how the sheep is walking. Your vet may clean the foot, inspect all four feet, and score lesion severity. They may also check whether multiple sheep are affected, whether recent weather has been wet, and whether new animals were introduced without quarantine.

In more complicated cases, your vet may recommend swabs, PCR testing, or laboratory submission to help identify bacteria involved or rule out other causes of severe lameness. Differential diagnoses can include footrot, interdigital dermatitis, trauma, abscesses, toe granulomas, and less common hoof disorders.

Because treatment choices can differ by lesion stage, mixed infection status, and flock goals, a precise veterinary assessment is worth it. It also helps your vet build a realistic flock-control plan instead of treating one painful foot at a time without addressing the bigger pattern.

Prevention starts with biosecurity. Any new or returning sheep should be quarantined and have their feet checked before joining the flock. Sheep with lameness should be identified early, separated, and examined promptly. Waiting to see if they improve on their own gives infectious hoof disease more time to spread.

Good footing and dry housing matter. Wet, muddy areas soften the skin and hoof horn, which can make infection easier to establish. Improving drainage, reducing crowding around feeders and waterers, and keeping bedding cleaner can lower risk. Regular observation is also important, because early coronary band lesions are easier to miss than obvious hoof loss.

Your vet may also recommend a flock plan for footrot control, since interdigital dermatitis and footrot can increase CODD risk or occur alongside it. That plan may include quarantine protocols, treatment of lame sheep without aggressive routine trimming, and culling of chronic repeat offenders when appropriate.

There is no single prevention step that works for every flock. The best plan depends on stocking density, climate, housing, pasture conditions, and whether other hoof diseases are already present. A practical conversation with your vet can help match prevention steps to your flock's real-world setup.