Occurrence of bovine mastitis in grade B milk farms in the state of São Paulo

Abstract

From March/1991 to February/1992 1,683 cows from seven grade "B" milk producing dairy farms were used in a study on the prevalence of bovine mastitis. GMT tests (7,695) were 47.0% negative; 15.1% " +" and 37.5% "++/+ + +". CMT scores were grouped by number of lactation (1st, 2nd, 3rd or more) and by stage of lactation (1-30 days in milk; 31-90 days; 91-250 and >; 250 days). Both stage of lactation and number of lactation had significant effect on % of cows CMT "++/+ + + ". Microbiological results from 983 milk samples were 50.97% positive. From the positive samples were isolated Staphylococcus sp (44.6%), Corynebacteríum sp (15.0%), Streptococcus sp (8.2%), Yeast/Fungi (5.4%). Bacillus sp (4.4%), E. coli (3.2%) and Klebsiella sp (0.2%). Considering both pure and mixed culture isolation, Staphylococcus sp represents 55.6%, Corynebacteríum sp, 18.6% and Streptococcus sp, 15.0%.