STUDIES ON THE CAUSES OF BACTERIAL MASTITIES IN TWO DAIRY BOVINE FARMS IN NORTHEASTERN BULGARIA AND THEIR SENSITIVITY TO ANTIMICROBIAL PRODUCTS

The prevalence of clinical and subclinical mastitis in two dairy farms with 500 and 114 cows each was studied. The causative agents have been identified and their antimicrobial susceptibility has been determined. In farm A, 44 cows (8.8%) with mastitis were observed - 3 with clinical and 41 with subclinical forms. Pathogenic microflora was isolated from 35 cows (79.5%). Were identified 64 strains: 30 (46.9%) Streptococ-cus spp. and 34 (53.1%) Staphylococcus spp. All staphylococci and streptococci showed sensitivity to Amoxi-cillin/Clav. acid. All staphylococci also showed sensitivity to Cephalothin, Gentamicin and Rifampicin. In farm B, 26 cows (22.8%) with mastitis were diagnosed - 10 with clinical and 16 with subclinical forms. Pathogenic microflora was isolated from 19 cows (73.1%). Were identified 24 strains: 8 (33.3%) Streptococcus spp. and 16 (66.7%) Staphylococcus spp. All streptococci showed sensitivity to Amoxicillin, Amoxicillin/Clav. acid, Cephalothin, Erythromycin, Gentamicin, Tetracycline, Rifampicin and Enrofloxacin. Susceptibility to Amoxicillin/Clav. acid, Cefoxitin, Cephalothin, Lincomycin, Gentamicin, Tetracycline, Rifampicin and En-rofloxacin was found in all staphylococci.
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