Experimental and field sulfaquinoxaline toxicosis in Leghorn chickens

Mortality of 47% occurred in a commercial flock of 20-week-old leghorn pullets treated with 0.05% sulfaquinoxaline in the feed. The drug was given for 2-3 days, removed for 2 days, and fed again for 2-3 days. Gross lesions consisted of disseminated hemorrhages, bone marrow pallor, a variety of changes suggesting septicemia, and overwhelming bacterial infection. Experimental feeding of sulfaquinoxaline at 0.05% in the feed at a schedule of 3 days on, 3 days off, and 2 days on successfully reproduced the essential features and gross lesions of the field toxicosis. Mortalities of 32.5% and 43.5% were observed in sulfaquinoxaline-treated groups. A high incidence of gangrenous dermatitis occurred in chickens with the experimental toxicosis, but it was not observed in the field case.