DRUG RESIDUES IN UNMEDICATED PIGS

The concentration of sulfadimidine was measured in the urine of pigs w hich were housed (over five days) in boxes where other pigs have been treated orally with sulfadimidine before. Sulfadimidine was measured i n the urine of the unmedicated pigs in a concentration of up to 4 mu g /ml. Considering these urine concentrations, violative sulfaclimidine tissue residues would be expectable in the carcass after slaughter. Th e practice of fixing withdrawal times must be considered again to ensu re that drug residues in tissues are below the MRL before slaughter al so in unmedicated animals.