Residues of gentamicin in eggs following medication of laying hens.

1. Gentamicin was injected subcutaneously and intramuscularly into 5 groups of 10 laying hens and its concentration was determined in albumen, yolk and whole egg. 2. Groups 1 and 3 were intramuscularly injected with doses of 10 and 25 mg/kg while groups 2, 4 and 5 were subcutaneously injected with doses of 10, 25 and 50 mg/kg, respectively. 3. The final gentamicin concentration in albumen was measured on d 3 for groups 1 and 2; on d 4 for groups 3 and 4, and on d 5 for group 5. Concentrations in yolk and whole egg were measured on d 7, 10 and 12. 4. Gentamicin recovery was as follows: 2% in groups 1 and 2, 2.5% in groups 3 and 4, and 3% in group 5. 5. Most of the residue (approximately 90%) was recovered from the yolk.