ABSTRACT
F. necrophorum [62.0%], B. melaninogenicus [43.0%], P.aerobius [34.0%], C. sporogenes [18.0%], F. mrotiferum [18.0%], B. fragilis [12,0%] and C. perfringens [12.0%] were the most prevalent obligate anaerobic organisms isolated from bovine interdigital dermatitis. The pathogenicity of F. necrophorum in mice was related to the route of infection. Intrahepatic route was the most virulent route with mortality rate [86.7%]. Mortalities with s/c or i/p routes reached 53.3% and gross lesions were discussed in details. The in vitro sensitivity of 20 strains represented each of F. necrophorum, B. melaninogeneicus and P. anaerobius to 16 chemotherapeutic agents were described in details. Oxytetracycline, enerofloxacine and danofloxacine were the most effective drugs against the majority of tested anaerobic microorganisms