ENZYME-IMMUNOASSAY OF ANTIMICROBIALS IN C OWS MILK AFTER THERAPEUTIC APPLICATION

Milk samples of 107 cows treated with antimicrobials in veterinary pra ctice were analysed by enzyme immunoassay (EIA) methods. The following veterinary drugs were used, either as single substances or in compose d formulas: tetracycline, chlortetracycline, dihydrostreptomycin, sulf amethazine, sulfadiazine, sulfamethoxypyridazine and trimethoprim. The results for the mean and maximal secretion of these drugs after intra mammary, intravenous, intramuscular or intrauterine treatment showed t hat no drug residue levels above the individual maximum residue limits , as set in accordance with regulation 2377/90 within the European Uni on, were present in milkings corresponding to the respective withdrawa l periods, but low residue concentrations near to the detection limits (5-20 ng/ml) could still be found in some of these samples.