Abstract
The research was done on the herd (n = 3000) of cows of black-motley breed with an admixture of Holstein. At the first stage, the diagnosis was carried out by using the Keno test. There were selected 148 (4.9%) cow, which had of subclinical mastitis. For treatment, there were used the schemes tried and tested in the farm: (1) nisin, polymexin B, ketoprofen, methyl salicylate; (2) nisin, polymexin B, ketoprofen, ceftiofur; (3) amoxicillin, ketoprofen, methyl salicylate, prednisone. Before it, the allocation of pathogens was not carried out. After treatment the number of repeated cases of the disease reached 44.6%, which indicated the ineffectiveness of the treatment regimens used. At the second stage, samples of milk, nasal and vaginal mucus were taken from animals with a relapse of mastitis. Different pathogens were used to isolate pathogens (Staphylococcus aureus, Escherichia coli, Shigella spp., Enterococcus spp., Ps. aeruginosa). The extracted isolates were identified based on the cultural and biochemical properties. The results were interpreted on the recommendation of EUCAST. Of all the animals examined, they simultaneously detected in milk 3 pathogens in 37.8%, 2 pathogens in 40.9%, and only one pathogen was isolated in 21.3%. Moreover, S. aureus (84.8%), Ps. aeruginosa (62.1%), Enterococcus spp. (34.8%) was found in smears from the vagina. The sensitivity of the selected pathogens to antimicrobials showed that 73% of S. aureus strains were resistant to ≥6 antibiotics, 47% E. coli to ≥7, 34% Shigella spp. to ≥4 and 21% Ps. aeruginosa to ≥4. The use of antibiotics of different groups without isolating the pathogen and determining its sensitivity leads to the appearance of multiresistant strains of bacteria and culling animals from the herd. This work was supported by the Ministry of Science and Higher Education of Russia (AAAA-A18-118021590136-7) and the Russian Science Foundation (project 20-16-00106).