This study involved two experiments which examined the efficacy of 'in water'
tilmicosin medication for the treatment of experimental Mycoplasma gallisepticum (MG) disease. The first experiment investigated
tilmicosin concentrations of 50, 100, 200 and 400 mg/l administered for 5 days. In the second experiment, dose levels of 50, 75 and 100 mg/l
tilmicosin administered for either 3 or 5 days were investigated. The first experiment suggested that
tilmicosin was effective in reducing the incidence and severity of airsacculitis lesions caused by MG. In the second experiment
tilmicosin treatment was found to significantly reduce the severity of airsacculitis caused by MG, although there was no effect on the morbidity. These experiments suggest that
tilmicosin is effective in the treatment of MG
infections when administered in
drinking water. The minimum effective concentration of
tilmicosin in
drinking water appears to be at or less than 50 mg/1 when administered for either 3 or 5 days.