The use of a homologous standardized inoculum of Anaplasma marginale was compared to a chemoprophylatic method, using dihydrate oxytetracycline, considering reduction of rickttsemia and packed cell volume (PCV), during A. marginale infections in calves. The animals that had received the inoculum (10(7) A. marginale infected erythrocytes) showed a 1.2% reduction of rickettsemia and the PCV decreased 23.0%, when challenged in the field. These values were statistically lower than those obtained from animals in the control group. As far as chemoprophylaxis is concerned, the animals that had been treated three times with dihydrate oxytetracycline (20 mg/kg) showed a 2.7% reduction of rickettsemia and the PCV decreased 36.3%. These values were also statistically lower than those obtained from animals in the control group. Both preventive measures proved to be efficient in reducing rickettsemia and decrease of PCV.
Anaplasma marginale; dihydrate oxytetracycline; chemoprophylaxis; standardized inoculum
