Swine veterinary drugs administered via the intra-muscular route. II. Persistence of damages at the injection site after the regulatory withdrawal time.

This study aimed to evaluate, after withdrawal period, muscular damages ind uced by intramuscular administration of veterinary drugs to swine. Conventi onnal pigs (females or neuter males) 5 to 6 months old, bred at farm, were used. Nine formulations containing aspirin, dexamethasone, sulfadoxine with trimethoprime, long acting amoxicillin, long acting oxytetracycline, penic illin G, flumequin, lincomycine and tylosine respectively were tested at th e noticed recommended doses. Injection sites were removed after the withdra wal period and lesions were examined using a macroscopic scoring method. Wi th 7 drugs, muscular damages were still observed in more than 50 % of the a nimals at the no-residue withdrawal time. These results are discussed from a regulatory point of view, for the choice of injection sites and the metho ds used to score the muscular lesions.