Анотация: The pathogenicity of Mycoplasma capricolum subspecies capricolum in Red Bororo (RB) bull calves was investigated. Two calves infected with 4.21 x 106 cells of Trypanosoma congolense and later inoculated endobronchially with 1.6 x 109 CFU / ml of M. capricolum subspecies capricolum (Tc/Mcc) died 38.0+-1.4 days post infection (pi) presenting fibrinous intersititial pneumonia and severe lymphoid depletion in spleen and lymph nodes