Sulfamethazine Blood and Milk Concentrations in Dairy Cows

Abstract

Sulfamethazine was administered to 4 normal cows, paren-terally, orally, and by infusion, at a dosage of 1.5 gr./lb. body wt. the 1st day and 1 gr./lb. body wt. the 2d day, and blood and milk detns. were made at frequent intervals after administration. Sulfamethazine diffuses freely from blood to milk and from udder to blood. Concns. in the milk of slightly less than half the free drug blood level were attained. All 3 methods of administration, at the dosage used, resulted in the attainment of blood and milk concns. considered to be bac-teriostatically effective. No evidences of systemic toxicity of the drug were noted.