DIGITAL DERMATITIS - REPORT OF AN OUTBREAK

An outbreak of digital dermatitis in a diary herd in Gauteng province of South Africa is described in which 72% of the lactating herd was af fected. Many of the affected cows showed a severe lameness and a drop in milk production. Other complications included heel horn erosion, un der-running of heel horn and boxy claws. The diagnosis was made on the typical clinical appearance of the condition and the presence of spir ochaetes on histopathological section from biopsy material. The condit ion responded to spraying affected feet with an oxytetracycline mixtur e after cleaning with water using a high pressure hose. The prevalence was reduced to 28% after one month of therapy. A repeat outbreak occu rred on the same farm 7 months later during which time 37% of the lact ating herd was affected. Of the cows affected, 48% represented new cas es, whereas the rest were reinfection.