Abstract
Fifty-day-old chickens were administered with 0.2 per cent (group A), 0.4 per cent (group B), and 1.0 per cent (group C) of sulfadimethoxine mixed with a diet. In groups B and C, medication was continued for 30 days. In group A, consecutive 3 or 4 days' medication was alternated with a 2 or 3 days' recess.
Feed intake was reduced with an increase in the additive. In groups B and C occurred diarrhea and soft feces. Many chickens of these groups manifested anemia and weakness about 10 days after medication, showing 27 per cent the rate of increase of body weight among the control ones.
The average serum level of the drug in total and in free amount was 19 and 14 mg, respectively, in groupB and 30 and 26 mg in group C.
Autopsy revealed hemorrhagic changes in groups B and C on and after the 15th day after medication. They seemed to have been induced by vitamin K deficiency, which might have been caused indirectly by the long-term medication.
Neither hematological nor histological examination proved any noticeable toxicity of the drug.
