Nuflor - BRD and Foot Rot

Foot Rot: Causes, Incidence, Signs, Diagnosis, Treatment, and Control

Foot rot, also known as foul in the foot and interdigital necrobacillosis, is an infectious disease of cattle characterized by inflammation of the sensitive tissues of the feet and severe lameness.

Causes of Foot Rot

Foot rot is usually described as being caused by Fusobacterium necrophorum bacteria, but Bacteroides melaninogenicus bacteria also have been identified as possible causes. The disease appears contagious, and incidence is much higher during wet, humid weather or when conditions are wet underfoot. Stony ground, lanes filled with sharp gravel, and pasture of coarse stubble also predispose to the condition.

Discharges from the feet of infected animals are the probable source of infection. Bacteria enter through abrasions into the skin on the lower part of the foot. Such abrasions are more likely to occur when the skin is swollen and soft due to continual wetness, such as often occurs from rain in summer and autumn months. Persistent wet conditions also may favor persistence of the bacteria on pasture land.

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Incidence of the Disease

Cattle of all ages, including young calves, may be affected by foot rot, but the disease is much more common in adults. It has been observed that Brahman or Zebu-type cattle (Bos indicus) are more resistant than British breeds (Bos taurus) to infectious foot rot.

The disease is common in most countries and is of greatest economic importance in dairy cattle. It reaches the highest level of incidence in dairies, because of the intensive conditions under which the cows are kept. In beef cattle on range, the incidence is usually low, but many cases may occur in purebred herds and feedyard cattle. Under conditions favoring infection, as many as 25 percent of a group can be affected at one time, but the usual picture is for the disease to occur sporadically on contaminated premises.

Loss of production occurs in affected cattle, and an occasional animal may suffer a serious involvement of the joint and other deep structures of the foot; these may require amputation of a claw.

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Observable Signs of Foot Rot

Severe foot lameness appears suddenly, usually in one limb only, and may be accompanied by a moderate systemic reaction, with fever of 103° to 104°F. There is temporary depression of milk yield in cows, and affected bulls may show temporary loss of libido. An affected animal puts little weight on the leg, although it will only carry the leg off the ground when severe joint involvement occurs. Swelling of the coronet and spread of the claws are obvious.

The typical lesion of foot rot occurs in the skin at the top of the cleft between the claws. It takes the form of a fissure, with swollen, protruding edges that may extend along the length of the cleft or be confined to the front part or the part between the heel bulbs. Pus is never present in large amounts, but the edges of the fissure are covered with dead tissue, and the lesion has a characteristic foul odor. Occasionally in early cases, no external lesion may be visible, but there is swelling of the coronet and lameness. Such cases are usually designated "blind fouls" and respond well to injectable antibiotics.

Spontaneous recovery sometimes occurs, but if the disease is left untreated, the lameness usually persists for several weeks, with adverse effects on milk production and condition. The incidence of complications is also higher if treatment is delayed, and some animals may have to be destroyed because of local involvement of joints and tendons. In such cases, lameness is severe, the leg is usually being carried, and the animal strongly resists handling of the foot. Swelling is usually more obvious and extends up the back of the leg. Response to medical treatment is usually poor, and surgical measures are usually necessary to drain the wound.

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Diagnosis of Foot Rot

The characteristic site, nature and smell of the lesion, the pattern of the disease in the group, and the season and climate are usually sufficient to indicate the presence of true foot rot. Careful examination of the foot can usually differentiate foot rot from traumatic injuries to bones and joints, puncture wounds, bruising of the heels, and gross overgrowth of the hoof. Laminitis also may cause lameness, but no local foot lesions occur.

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Treatment Options

Administration of injectable antibiotics or sulfas and local treatment of the foot lesion are necessary for best results. Immediate treatment as soon as possible after the onset of swelling and lameness will give excellent recovery in 2 to 4 days. When treatment is delayed for a few days after the onset of signs, severe lesions may develop and cause an extended recovery period.

Local treatment includes scrubbing the lesion, removing all dead tissue, and applying any suitable topical antibacterial preparation. It should be secured with a pad and bandage that can be left on for several days. A wet pack of 5 percent copper sulfate solution also is inexpensive and effective.

If conditions underfoot are wet, the animal should be kept stabled in a dry stall. In cattle running at pasture, or in the case of large numbers of feedyard cattle, local treatment is often omitted because of the time and inconvenience involved. In an outbreak, however, affected animals should be identified with a marker, to avoid subsequent confusion. Local treatment may not be necessary at all in the early stages of the disease if the animal can be prevented from gaining access to wet, muddy areas.

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Control Measures

Prevention of foot injuries by filling in muddy and stony patches in barnyards, lanes, and feedyard alleys will reduce the incidence of foot rot. On dairy farms, providing a footbath with an approved medication in a doorway, so that cattle have to walk through it twice daily, may be affective.

Commercial vaccines to prevent foot rot are available and appear to provide protection against the toxins produced by the bacteria that cause the disease.

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Veterinary Consultation

The information presented here is not a substitute for veterinary consultation. Contact your veterinarian for complete herd and feedyard health management programs.

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