Study of Subclinical Mastitis in Dairy Herds of North Paraná, Brazil

Abstract

California Mastitis Test (CMT) was performed in five hundred and three Holstein cows from the north region of Paraná. One hundred and fifithy of these cows (29,82%) and 295 quarters in the CMT were positives. In 223 milk samples was observed bacterial growth (213 pure cultures and 10 associated cultures). The most commonly agents isolated in pure growth were, staphylococci (30,51%), whereas S. aureus (17,97%) and coagulase negative staphylococci (12,54%), streptococci (21,69%) and C. bovis (18,98%). Colonie's counter was performed in 193 milk samples. Of these samples, 9 had less than 3 x 102 CFU/ml, 22 had between 3 x 102 to 103 CFU/ml, 17 had between 103 to 3 x 103 CFU/ml and 145 had more 3 x 103 CFU/ml. The mean somatic cell count for the main agents isolated were 2,9 x 106/ml for streptococci, 2,5 x 106/ml for S. aureus, 1,2 x 106/ml for CNS. The most commonly species of CNS were S. hyicus (25,00%), S. chromogenes (15,00%), S. epidermidis(~\ 5,00%), S. simulans (5,00%) and S. warneri(5,00%). Thirty comma thirty percent of 33 isolated, were resistant to lincomycin, 27,27% to tetracycline, 18,18% to penicillin and novobiocin, 15,15% to ampicillin and erytromycin.