Digital dermatitis is a painful foot condition that causes severe lameness in cattle.
This highly contagious disease was first described in Italy in 1974 and has since spread around the world, primarily within dairy cattle.
However, the disease is also becoming an emerging threat in beef cattle.
It is most common in cattle kept in confinement, and although it can affect breeding cows, it has been identified primarily in feedlot cattle within the beef industry.
A research study in 2000 in southeastern United States identified digital dermatitis in 29 percent of culled dairy cattle at the packing plant. The same study said four percent of culled adult beef cattle had lesions of digital dermatitis.
Outbreaks have been anecdotally reported in feedlots in Western Canada.
Digital dermatitis goes by many names including strawberry foot rot, raspberry heel, foot wart and hairy heel wart.
The hind legs are affected in 85 percent of cases.
These lesions may appear initially as a raw, red, oval ulcer on the back of the heel just above or at the coronary band.
Many of them often develop raised, hair-like projections or wart-like lesions, and some may extend up between the claws or appear on the front of the foot.
These raw skin lesions are incredibly painful, and cows will dramatically alter their gait and posture to avoid putting pressure on them. Animals will walk on their toes because the lesion is usually at the heel, which may cause the hoof on the heels to overgrow.
This condition may resemble a wart, but it isn’t because warts are caused by a virus. This disease is caused by a bacterium in the “spirochete” family called treponema.
Researchers still disagree about whether other pathogens are in-volved, but treponema has been the primary organism associated with digital dermatitis.
There are likely predisposing factors such as immunity, infectious and environmental components.
Wet conditions and constant moisture with manure contamination are probably responsible for softening the skin and allowing the organism to penetrate the skin surface.
The disease is highly contagious and can spread rapidly and affect a large percentage of animals once introduced via the addition of new cattle into a herd.
Younger cattle tend to be more susceptible, and cases in dairy cattle tend to occur around calving. This suggests that immune system suppression may play a role in the disease.
Treatment has proven to be difficult and usually requires cleaning and drying the lesion and then applying an antibiotic on the skin in a bandage or with a topical spray.
Antibiotic sprays, which are usually a tetracycline mixture, need to be applied twice daily, which is feasible in a dairy herd but highly difficult in a feedlot setting.
Injectable antibiotics are often used in conjunction with topical treatments, but there is limited evidence that they are helpful.
Prevention is focused on hygiene and pen conditions by trying to reduce stocking density, maintaining watering and feeding areas to avoid mud and manure accumulation and managing corrals to avoid wet areas.
Foot bath solutions such as copper sulfate, zinc sulfate and formalin control the disease in dairy herds but can be difficult to manage in beef cattle.
Cattle that live in settings where manure management is difficult to achieve should walk through foot baths twice a day for at least five days a week, but this is difficult to achieve in a feedlot.
Once-a-week foot baths may be sufficient in more hygienic conditions, which is more practical in beef cattle herds.
Producers should consult a veterinarian before starting a treatment program. Foot baths require considerable effort to manage and need to be long enough and deep enough to allow for two dunks for each foot.
Researchers are attempting to create a vaccine, but results have not been promising.
Producers can attempt to prevent bringing digital dermatitis into their herds by avoiding contact with infected dairy cattle.
Hoof trimmers should disinfect their equipment between farms to avoid spreading this highly contagious disease.
John Campbell is head of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.