Foot rot in breeding bulls can be a more serious issue. Lame bulls will be reluctant to breed and if fever is associated with the infection, spermatogenesis can be adversely affected
Bovine interdigital necrobacillosis, or foot rot, is a common disease causing lameness in cattle. It is caused by a bacterial infection, can affect any age of cattle and can occur in dairy barns, on pastures and in feedlots.
Characteristic clinical signs of foot rot are the swelling of the foot with spreading of the claws. Cattle become suddenly lame and the lameness can often be severe. The swelling and damage to the tissues can cause significant pain and infected cattle are often reluctant to move and may spend more time lying down and eating less. Usually, only one foot is involved and cattle often will have an elevated temperature. The lesion on the foot will often have a characteristic odour.
The bacteria that is usually involved is Fusobacterium necrophorum; however, other bacteria may be important causal agents as well. F. necrophorum is a very common organism and can be found anywhere cattle are found. Infection results when the skin around or between the claws is cut, cracked or punctured and the bacteria get into these wounds. Although not completely understood, it is thought that an exotoxin the bacteria releases is responsible for the swelling and necrosis (rotting) of tissues. The disease is more common during wet, humid weather and when animals are overcrowded. Soil with a high pH can have higher incidence of infection. Cattle that are on rough ground or on fields that have been recently harvested can have an increased incidence of foot rot.
It is important to remember that not all causes of lameness in cattle are the result of infection. Injuries to the sole of the hoof, tendon injuries and muscle injuries can also cause lameness. Fibromas (corns) can also form between the toes and cause significant lameness. It is essential to properly diagnose lameness to provide the appropriate treatment and reduce the use of antibiotics.
Most cases of foot rot require treatment with appropriate antibiotics. Sometimes the condition may resolve without treatment, however, treatment is recommended to reduce the chances of more serious complications such as joint, bone and tendon sheath infections. Pencillins, oxytetracyclines, and ceftiofur are commonly used antimicrobial agents. With treatment the condition is generally resolved in four to five days. The use of anti-inflammatory medications may also be indicated to reduce the inflammation associated with infection. If the infection does involve deeper tissues, longer courses of treatment may be required. In some cases the infection can spread into joints, bone or form chronic abscesses. These can be difficult to resolve. If this occurs, and only one claw is affected, the animal may require surgical removal of the claw. Infection of bones and joint can be difficult, if not impossible, to treat and often result in euthanasia of the animal.
Foot rot in breeding bulls can be a more serious issue. Lame bulls will be reluctant to breed and if fever is associated with the infection, spermatogenesis can be adversely affected. This can result in the bull being infertile for a period of time. For the cow-calf producer, significant economic loss can result from decreased fertility leading to open cows and extended calving periods.
The incidence of foot rot can be reduced by avoiding conditions that predispose cattle to infection. Depending on the type of operation this can be easy or very difficult. Having cattle with good hoof conformation will also help. There is a vaccine that can reduce the incidence of foot rot. Vaccination is often recommended for breeding bulls where the cost associated with disease is greatest. Talk to your veterinarian for more information on protocols for treating and preventing foot rot.
Dr. Troy Bourque, a cow-calf veterinarian and owner of Sheep River Veterinary Services in Okotoks, Alta., is a member of the Western Canadian Association of Bovine Practitioners, who co-ordinate this column.
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