PSX-B-21 - Diagnosis of early mastitis in dairy cows: somatic cells and bacterial pathogen measuring

Mastitis is an inflammatory condition of the breast that can be caused by chemical, physical, traumatic injury or bacteria. In recent years, biomarkers for the mastitis diagnosis have been actively studied. The aim of the study was to assess the relationship between SCC and pathogenic bacteria in milk occurrence. The study carried out by milk samples collected in the experimental herd (Krasnodar region, Russia) from 85 Holsteinized Black-and-White cows. Healthy cows (HC; n = 4), cows at risk for clinical mastitis (RCM, n = 22), subclinical (SCM; n = 25) and clinical mastitis (CM; n = 34) groups were divided by a bacteriological cultivation and SCC level (Fossomatic7 DC). SCC results were logarithmically converted to SCS. Consequent groups were included animals with SCS level: HC (SCS < 4.1), RCM (4.2≤SCS≤5.3), SCM (5.4≤SCS≤6.3), CM (SCS >6.4). HC group of animals showed SCS equal to 3.11±0.28, 4.85±0.44 for RCM, 5.8±0.28 for SCM and 7.43±0.87 for CM. Identification of isolated bacteria species was carried out by conventional biochemical methods using the API20E, APIStaph, API20Strep tests (bioMerieux SA,France). Number of isolated pathogenic bacteria in CM group was 57 strains of which 33.3% were attributed to Enterobacteriaceae, 45.6% to coagulase-negative staphylococci (CONS), 12.3% to S.aureus and 8.8% to Ps.aeruginosa. In SCM group there were assigned 48 strains: 32.5% to Enterobacteriaceae strains, 42.5% to CONS, 20.0% to S.aureus, 5.0% to Ps.aeruginosa. The antibiotic susceptibility was determined according to NCCLS and EUCAST. S.aureus isolates showed the highest sensitivity to erythromycin (4.3% of resistant strains) and the highest resistance to ciprofloxacin (100%), tetracycline (95.0%), rifampicin (88.5%), benzylpenicillin (79.3%), novobiocin (69.2%) and fusidin (65.5%). The primary analysis of SCC and milk microbiological profile can be able to increase the accuracy of mastitis occurrence diagnosing that contributes to taking the right decision for choosing an antibiotic to preserve the cows’ health in Russian cattle population. The study was funded by RSF (project No.21-76-20046)