RESUMO
One hundred and ten milk samples were collected from 35 dairy cows with recurrent mastitis and 75 apparently healthy ones. The field application of California Mastitis Test [CMT] on the apparently healthy cows indicated 60% [45 out of 75 cows] with sub-clinical mastitis. The estimation of SCC recorded 31.8% [35 samples] above Ixl0[6] cell/ml, 40.9% [45 samples] were ranged between 4xl0[5] to Ixl0[5] cell/ml and 27.3% [30 samples] were less than 4xl0[5] cell/ml. The bacteriological examination revealed 10% facultative anaerobic bacteria from normal milk samples, while both facultative and obligatory anaerobic bacteria were 62.2% from sub-clinical and 100% from clinical mastitic milk samples. The highly effective antibiotics on the isolated bacteria in the laboratory were florofenicol, tetradelta, gentamicin, amoxicillin-clavulanate, refampicin and metronidazol