by Mark Johnson, Oklahoma State University

Recent rains have led to many beef producers seeing a high incidence of foot rot in beef herds. Foot rot is an acute or subacute necrotic (decaying) infectious disease that causes swelling and lameness in at least one foot. The disease can cause severe lameness, decreased weight gain and lower milk production. Lame bulls and females will be reluctant to breed.

If treatment is delayed, deeper structures of the foot may become infected, leading to chronic disease and poor recovery prognosis. Severely affected animals may need to be culled. The incidence of foot rot varies according to the weather, season of the year, grazing conditions and housing environment. Approximately 20% of all diagnosed lameness in cattle is actually foot rot.

Cause

Fusobacterium necrophorum is the bacterium most often isolated from infected feet. This organism is present on healthy skin, but it needs injury or wet skin to enter the deeper tissue. F. necrophorum appears to act cooperatively with other bacteria, such as Porphyromonas levii, Staphylococcus aureus, E. coli and Trueperella pyogenes, thereby decreasing the infective dose of F. necrophorum necessary to cause disease. Prevotella intermedia has also been implicated as a causative agent for foot rot.

Normal healthy skin will not allow the bacteria to enter the deeper tissues. Moisture, nutrient deficiency, injury or disease can result in compromised skin or hoof wall integrity, increasing the likelihood of the bacteria invading the skin. Deficiencies of zinc, selenium and copper can lead to higher frequency of foot rot due to the important role these trace minerals play in skin and hoof integrity as well as immune function. Injury is often caused by walking on abrasive or rough surfaces, such as stony ground, sharp gravel and grazing stubble on recently mowed pasture, which may irritate the interdigital skin. Standing in pens or lots heavily contaminated with feces and urine softens the skin and provides high exposure to the causative bacteria. High temperatures and humidity will also cause the skin to chap and crack, leaving it susceptible to bacterial invasion.

Clinical signs

Foot rot occurs in all ages of cattle, with increased incidences during wet, humid conditions. When case incidence increases in hot and dry conditions, attention must be directed to loafing areas, which are often crowded and extremely wet from urine and feces deposited in small shaded areas. The first signs of foot rot include:

• Extreme pain leading to sudden onset of lameness, which increases in severity as the disease progresses.
• Acute swelling and redness of interdigital tissues and adjacent coronary band.
• Lesions in the interdigital space are often necrotic along its edges and have a characteristic foul odor.
• Evenly distributed swelling around both digits and the hairline of the hoof, leading to separation of the claws.
• Loss of appetite.

Treatment

Treatment of foot rot is usually successful, especially when started early. Treatment should always begin with cleaning and examining the foot to establish that lameness is actually due to foot rot. A veterinarian may advise recommended antibiotics and dosages for each situation. Use of a nonsteroidal anti-inflammatory product may be indicated for pain relief. There are multiple antimicrobial products labeled for the treatment of foot rot. These products should be used rather than using another product in an extra-label manner. A product specifically labeled for pain associated with foot rot is now available.

When possible, affected animals should be kept in dry areas until healed. If improvement is not evident within three to four days, it may be an indication the infection has invaded the deeper tissues. Infections not responding to initial treatments need to be reevaluated by a veterinarian in a timely manner.

Prevention

Prevention and control of foot rot begins with management of the environment. Prevention of mechanical damage to the foot caused by frozen or dried mud, brush stubble and gravel is desirable. Minimize animals’ exposure to sharp plant stubble and sharp gravel. Attempt to minimize the time cattle must spend standing in wet areas. Pens should be well-drained and frequently scraped. Areas around ponds, feedbunks and water tanks should be maintained to minimize mud and manure.

Summary

Foot rot is a major cause of lameness in cattle and can have a severe economic effect on animal health, animal performance and enterprise profitability. Skin and hoof lesions allow bacteria to invade live tissue. Therefore, the most important preventive measures are centered on the protection of interdigital skin health. Important preventative measures include a well-balanced mineral nutrition program and minimizing exposure to conditions that may cause skin or hoof injury. Treatment is frequently successful if the disease is diagnosed and treated soon after symptoms develop.

Reference: Foot Rot in Cattle OSU Cooperative Extension Fact Sheet AFS-3355

Editor’s note: Mark Johnson is a beef cattle breeding specialist with Oklahoma State University Extension. Johnson regularly contributes to the Cow-Calf Corner, an OSU Extension newsletter targeted toward cattle producers.

Angus Beef Bulletin EXTRA, Vol. 16, No. 5-A