||This article contains instructions, advice, or how-to content. (May 2011)|
Foot rot, or infectious pododermatitis, is a hoof infection commonly found in sheep, goats, and cattle. As the name suggests, it rots away the foot of the animal, more specifically the area between the two toes of the affected animal. It is extremely painful and contagious. It can be treated with a series of medications, but if not treated, the whole herd can become infected. The cause of the infection in cattle are two species of anaerobic bacteria (bacteria that can grow without oxygen), Fusobacterium necrophorum and Bacteroides melaninogenicus. Both bacteria are common to the environment in which cattle live, and Fusobacterium is present in the rumen and fecal matter of the cattle. In sheep, the Fusobacterium necrophorum first invades the interdigital skin following damage to the skin, and causes interdigital lesions and slight inflammation. The second stage of the disease is marked by the invasion of the foot by the foot rot bacterium Dichelobacter nodosus, a Gram-negative anaerobe. Usually, there is an injury to the skin between the hooves that allows the bacteria to infect the animal. Another cause of foot rot may be high temperatures or humidity, causing the skin between the hooves to crack and let the bacteria infect the foot. This is one of the reasons foot rot is such a major problem in the summer. Foot rot is easily identifiable by its appearance and foul odor. Treatment is usually with an antibiotic medication, and preventing injury to the feet is the best way to prevent foot rot.
The disease is different in cattle and sheep and cross-infection is not thought to occur.
Signs of infection
The first sign of a foot rot infection is when the skin between the claws of the hoof begins to swell (cellulitis). Swelling usually appears 24 hours after infection. The skin between the toes may be very red and tender and the toes may separate because of all the swelling. This is very painful to the animal and can cause lameness. The animal may also have a raised body temperature. A crack can develop along the infected part and is yellow in color. The foot will have a foul odor. Tendons and joints in the area can become infected, which is much harder to treat. A condition known as "super foot rot" is seen in some animals. Super foot rot infection occurs much faster and is usually much more severe. Most normal foot rot treatments will not cure this foot rot and a veterinarian should be contacted immediately.
The best way to treat foot rot is to catch it as early as possible. The infected animals should be separated away from the herd as soon as possible to prevent the infection from spreading and allow the animal a better environment for healing. The first treatment is to clean the foot thoroughly and examine the foot to determine it is definitely foot rot causing the infection. Keeping the wound clean and using an antibiotic ointment may help reduce the spread of infection. Foot rot is usually treated with an antimicrobial product. Penicillin, tetracycline, and other antibacterial medicines are often used to treat normal cases of foot rot. Usually, the antimicrobial product is nonprescription, but sometimes a veterinarian may choose to use a prescription medication. It is critical to closely monitor the animals to make sure they are responding to treatment. The infected animals should be kept dry until the healing has occurred. If the animal is showing no signs of recovery after three to four days, the bacteria could have infected the other tissues of the foot. Infusing antibiotic into the veins of the foot may be an effective way to treat those cases. Claw amputation and in very severe cases, euthanasia, may also have to be considered.
The infected animals can serve as the source of infection for the whole herd because they will spread the bacteria throughout the environment. The bacteria can live without a host for up to seven days. Once another animal gets a cut or crack in the soft tissue between its toes, the bacteria can infect the animal. This is why infected animals must be kept away from the rest. A good way to prevent foot rot is to keep any foreign objects that may cut or damage the foot out of the environment. This should be a practice regardless of whether a herd has foot rot or not. The cuts are what allow the bacteria to enter the foot tissue and cause the infection. Some cattle feeders add zinc to the feed mixes and may vaccinate the animals for foot rot. Zinc is important to maintaining the skin and hooves of cattle. Cattle deficient in zinc will become infected more easily than cattle with adequate zinc in their diets.
Vaccines have been developed but their efficacy is questionable and the immunity they provide is of short duration.
- Foot rot information
- W.G. Kvasnica, DVM, Ben Bruce, Ph.D., Ron Torell, MS. Foot Rot of Cattle. .
- Information on foot rot in sheep