1Department of Clinical Sciences, Faculty of Veterinary Medicine, Karaj Branch, Islamic Azad University,
2Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran,
3School of Mathematics, Statistics and Computer Sciences, University of Tehran, Tehran, Iran
A total of 183 coagulase negative Staphylococcal infected quarters and 64 uninfected quarters were randomly allotted to 4 experimental groups: infected quarters that did not receive any treatment (positive control group; n = 60); infected quarters that received Tylosin (n = 61) or Cefquinome (n = 62) and also uninfected quarters that did not receive any treatment were considered as negative control group (n = 64). Treated heifers received Tylosin or Cefquinome 10 to 14 days before the expected calving date. The bacteriological cure rate based on sampling obtained 3 days after calving was significantly higher (P<0.01) in mammary glands treated with systemic Tylosin (85.3%) than in the positive control group and mammary glands treated with systemic Cefquinome (69.4%). At the same time Tylosin treated heifers had significantly lower (P<0.01) somatic cell count scores compared to the positive control and Cefquinome groups. With the exception of one heifer that calved 8 days earlier than the expected calving date, there was no detectable antibiotic residues in the milk of the treated heifers on the 3rd day of lactation.