DANOFLOXACIN CONCENTRATION IN MILK, MILK- YIELD AND SOMATIC-CELL COUNT AFTER REPEATED INTRAMUSCULAR TREATMENTS OF DAIRY-COWS

Danofloxacin was injected intramuscularly in a daily dose of 1,25 mg/k g body weight to 8 cows (4 cows in early lactation; 4 cows in late lac tation) over 5 days. The Danofloxacin concentrations in milk (as sum o f Danofloxacin and Desmethyldanofloxacin) showed a level of 1 mu g/ml 12 h post treatment and 0,1 mu g/ml 24 h post treatment. Six milkings (72 h) after the last injection of Danofloxacin no milk residues above the detection limit (0,005 mu g/ml; HPLC) could be identified. The da ta of milk yield and somatic milk cells did not indicate any treatment related changes as did the clinical observations of the cows. Therefo re, a good local and systemic tolerance of Danofloxacin can be assumed . The favourable pharmacokinetic properties which result in Danofloxac in milk concentration above 0,10 mu g/ml (MIC for coliforms) for at le ast 24 h after a single i.m. injection will highly probably lead to th e future use of Danofloxacin as a mastitis drug.