Foot rot in cattle
Foot rot is usually characterised by acute inflammation of the skin and adjacent soft tissues of the space between the digits (interdigital space). It is accompanied by swelling, lameness and, in most cases, a foul-smelling necrotic lesion of the interdigital skin.
Causes and contributing factors
A number of bacteria usually present in the environment can cause infection of bovine feet. Healthy epithelium (skin) is resistant to bacterial organisms, while diseased or injured skin is susceptible to infection. High rainfall with wet faeces and mud can soften the interdigital skin, making it susceptible to injury.
Infectious agents gain entry through the skin as a consequence of injury caused by sharp pieces of stone, metal, wood, stubble or thorns. Other factors that may encourage damage to the interdigital skin include irritation and erosion of the interdigital skin caused by interdigital dermatitis, believed to be, in part, a consequence of the constant exposure of feet to mud and manure.
Clinical signs and diagnosis
The most obvious clinical sign of foot rot is lameness, which worsens as the disease progresses. There is inflammation and tissue death, resulting in swelling and pain. There is usually a bad smell associated with foot rot.
Cattle may stand with the foot raised, be reluctant to move, lose their appetite, lose weight, and have a low-grade fever and reduction in milk yield. Hind feet are affected most often and cattle tend to stand and walk on their toes. If left untreated, lameness becomes increasingly severe, with infection extending to the joints and other deeper structures of the foot.
Diagnosis of foot rot is made by observing the animal and physically examining the foot for the characteristic gross lesions. Cattle producers often diagnose any lameness associated with foot swelling as foot rot, but a more careful examination may reveal other causes of the swelling and lameness, such as injury or foreign bodies.
Ideally, move the animals to a paddock or yard that is not waterlogged and is free of abrasive footings. Clean the affected foot of mud and any tissue tags. Prompt diagnosis and initiation of antimicrobial therapy are essential to achieve a satisfactory response. The application of local treatments to the foot may assist; however, the treatment of choice is injectable antibiotics administered for 3-5 days.
In feedlot cattle, feed additives may be a better option for treatment (provided the animals are eating), especially if large numbers of cattle are involved. In pastured cattle that cannot be regularly yarded, the use of long-acting injectable antibiotics is needed, though response to treatment, especially in severe cases, is less successful than with daily injections. For very severe cases, an affected claw may need to be amputated to salvage the animal.
Cases that cannot be treated or fail to respond to treatment should be euthanised on humane grounds.
Preventative measures include removing sources of injury, and keeping feet dry and clean. Mud holes should be filled and stagnant pools drained or fenced off. Feedlots should be well drained and manure removed frequently. In areas where cattle walk frequently, such as in lanes or gateways, grading or filling in low areas to provide a well-drained pathway for walking may help to prevent foot rot cases. Pouring a concrete pad or establishing solid pads around feed bunks and water troughs will help keep feet dry.
In dairy cows, beef cows and bulls, regular foot care, including claw trimming as needed, helps prevent foot diseases and injuries. Animals may also be walked through a foot bath containing copper sulfate, zinc sulfate or formalin. Footbaths are more commonly used in dairies and may be impractical for most beef herds.