EN
There were performed clinical examinations of udders and milk samples taken from 2084 cows of 20 farms in which some difficulties in obtaining milk of high quality were noted. It was found that both a low milk yield and milk quality were associated with mastittis and poor hygienic state, and nutrition errors. Postitive resullts of CMT were on an average in 63,2% of cows (37.8—87.5%). The presence of bacteria was found in 46.5% (15.9—69.5%), subclinical mastitis in 9.5% (2.4—20.3%). Mastitis was caused by Streptococcus agalactiae on an average in 17.8% (0—49.0%), Str. dysgalactiae in 8.5% (0—20%), Str. uberis in 10.3% (2.0—42.9%), Staphylococcus aureus in 12.2% (0—38.7%), Staph. epidermidis in 29.2% (16.2—42.2%), Micrococcus spp. in 18.1% (7.7—35.7%), E. coli in 1.2% (0—4.3%), yeasts in 0.8% (0—35%). In no farm a complete control of mastitis was employed.