Foot-rot
Foot-rot is a term applied to the condition of feet of cattle, sheep, goats and sometimes pigs. It is characterized by inflammation, necrosis and ulceration of underlying tissues of foot. The disease is widespread in many tropical countries with highest incidence in sheep. The disease is related to climatic conditions. High temperature and humidity favour the disease. Foot rot in cattle and sheep is caused by Fusobacterium necrophorum complicated by Dichelobacter nodosus, especially in sheep.
Transmission: Animals in chronic state transmit infection directly to healthy animals. The sheep can remain as carrier for 3-4 years. Conditions of wetness and warmth favour the persistence of bacteria in the pasture. Infected cattle may often serve as the source of infection.
Symptoms: The earliest sign of foot-rot is swelling and moistness of skin of inter digital cleft. This is accompanied by lameness which increases as necrosis under-runs the horn in cleft. The animal may carry the leg or walk on its knees. In severe cases, there may be anorexia and fever. Symptom less carriers may be present for a period up to 3 years.A history of lameness in a flock is suggestive of foot-rot. This can be confirmed from clinical examination of typical lesions and microscopical examination of smears from the lesions after staining with Gram’s strain or Loeffler’s methylene blue. The organisms appear pink coloured short rods.
Diagnosis: It is difficult to diagnose foot-rot. Identification of Gram-negative bacilli is sufficient to diagnose the disease.
Treatment and control: wet pastures should be properly drained. The affected hooves of the diseased animals should be trimmed. The exposed infected tissue should be treated with 10% formalin or with chloramphenicol or tetracycline. The parenteral treatment with a mixture of penicillin and streptomycin is of value.