Residues of oxytetracycline in egg white and yolk after medication of laying hens

After intramuscular administration to laying hens, the highest mean concentration of oxytetracycline in (OTC) egg white was noticed on the Ist day after treatment (the 6th day of the experiment). On the 6 th day after treatment OTC was not detected. In the egg yolk, the highest OTC concentration was observed on the 3rd day after treatment. On the 13 th day after treatment no residues of oxytetracycline were detected above the detection limit of the used method (50 ppb). After oral administration, OTC residues appeared in the egg white as early as the first day after treatment began. The residues were detected until the 9th day after treatment. In the yolk, residues appeared four days after the beginning of the treatment and they were detected until the 12th day after treatment.