Sulfadimethoxine Withdrawal Time in Lactating Cows

Drug residues in milk have received much attention in recent months. Not surprisingly, the residue data collected by different groups, as well as the interpretation of its significance to public health, have been widely divergent The publicity generated has caused public concerns about the safety and wholesomeness of dairy products. Because of these concerns and the recognized need of the dairy industry to strictly comply with the FDA requirements regarding allowable tolerance of approved drugs in milk, Hoffmann-La Roche and Rutgers University recently conducted a study to confirm the established milk discard (withdrawal) time following administration of sulfadimethoxine as Albon once-a-day Boluses to lactating dairy cows. The original sulfadimethoxine tolerance of 10 ppb in milk, established after evaluation of extensive human food safety data by the Agency, remains in effect today. The recent study was conducted to determine if changes in dairy management and assay methods implemented since the original milk discard time was established, had changed the drug withdrawal time required to comply with the established tolerance.