Foot rot disease in cattle

HEAVY rains received this year came with a number of challenges for livestock farmers especially as it relates to diseases.

The disease prevalence and morbidity as well as mortality tend to increase with increase in predisposing factors such as increase in pathogens.

One disease which seems to have increased in incidence judging by numerous consultations from farmers if foot rot, an improperly named disease for animals whose feet are called hooves. Foot rot is a sub-acute or acute necrotic infectious disease of cattle which causes swelling and lameness in at least one hoof.

This disease can cause severe lameness and decreased weight gain or milk production. Lame bulls will be reluctant to mount because of the digital pain. Severely affected animals may need to be culled from the herd. Weight gain is significantly reduced when grazing cattle contract the disease.

The incidences of foot rot varies according to the weather and season of the year. Foot rot is usually random in occurrence, but the disease incidence may increase up to 25 percent in high-intensity beef or dairy production units.

The unusually wet conditions which were experienced this year increased the incidences of the disease. Farmers are advised to have more than one kraal so that animals can be rotated between the kraals. What one observed this year was animals penned in kraals which had mud up to knee-height. Consequently the animal goes through the whole night standing because it is simply not possible for it to lie down and rest.

Normal healthy skin will not allow the bacteria which causes foot rot to enter the deeper tissues. Mechanical injury or softening and thinning of the interdigital skin by puncture wounds or continuous exposure to wet conditions are necessary to provide entrance points for infectious agents.

Standing in environments heavily contaminated with dung and urine will soften and irritate the skin providing entry routes for the pathogens. High temperatures and humidity will also cause the skin to crack, leaving it susceptible to bacterial invasion.

Fusobacterium necrophorum is the bacterium most often isolated from infected hooves. This organism is present on healthy skin but it needs injury or wet skin to enter the deeper tissue. Once the skin breaks bacteria gain entrance into subcutaneous tissues and begin rapid multiplication and production of toxins, further stimulating continued bacterial multiplication and penetration of infection into the deeper structures of the foot.

Clinical signs of foot rot occurs in all ages of cattle with increased incidences during wet humid conditions.

The first signs of foot rot include extreme pain leading to sudden onset of lameness, which increases in severity as the disease progresses. There is also acute swelling and redness of interdigital tissues with lesions in the interdigital space and a characteristic foul odour. The disease progression may lead to evenly distributed swelling around both digits leading to separation of the claws.

The animal develops fever and goes off feed. Foot rot can affect both the front and hind limbs. Swelling attributable to foot rot involves both claws. It should be noted that there are other diseases which cause symptoms similar to foot rot and hence proper inspection is needed for accurate diagnosis. Treatment should always begin with cleaning and examining the foot to establish that lameness is actually due to foot rot. Most foot rot cases can be treated by use of systemic antimicrobial therapy.

Affected animals should be kept in dry areas until healed. Preventive and control of foot rot begins with management of the environment and prevention of mechanical damage to the hooves. Minimise the time cattle spend standing in wet areas.

Other preventive measures include footbaths especially for dairy operations. However, some animals that are affected by mild cases of foot rot will recover on their own when they are moved to drier handling pens.

Uyabonga umntakaMaKhumalo.

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