Residues of penicillin in the milk after intrauterine treatment of lactating cows

The penicillin is a broad-spectrum antibiotic, active against a large number of Gram-positive and Gram-negative microorganisms. A total of 14 cows (East Friesian sort) were divided into two equal experimental groups, and one group was administered a dose of 400.000 IJ/ i.u./cow, and the order group 800.000 IJ/ i.u./cow penicillin. The penicillin residues in milk was determined using of Delvo test SP method with B. stearothermophilus var. calidolactis, as the test mikroorganism. In the first group, the average duration of the presence of its residue in milk of treated cows was 37,7 (0-60) hours. After the intrauterine dose of 800.000 I.U./cow, this time period was an average of 53,8 (36-72) hours. The concentrations of penicillin residues at the intrauterine treatment dairy cows were determinined an average of 0,003-0,143 I.U./ml milk for dose of 400.000 I.U./cow, and an average of 0,008-0,325 I.U./ml milk for dose of 800.000 I.U./cow. Total excretion of penicillin residues per cow were an average of 1.288,2 (0-2.538) I.U./cow for dose of 400.000 I.U./cow, and an average of 6.149,1 (1.452-15.330) I.U./cow for dose of 800.000 I.U./cow.