AGRICULTURAL BIOLOGY, 2015, V. 50, ¹ 6, pp. 810-816 ISSN 2412-0324 (English ed. Online) (SEL’SKOKHOZYAISTVENNAYA BIOLOGIYA) ISSN 0131-6397 (Russian ed. Print) ISSN 2313-4836 (Russian ed. Online) Veterinary microbiology, microbiomes doi: 10.15389/agrobiology.2015.6.810rus doi: 10.15389/agrobiology.2015.6.810eng SCREENING OF DAIRY COWS’ HERD FOR PRESENCE IN MILK OF HEMOLYTIC MICROORGANISMS IN RELATION TO SOMATIC CELL CONTENT O.A. ARTEM’EVA, D.A. PERESELKOVA, I.V. VINOGRADOVA, E.N. KOTKOVSKAYA, E.A. GLADYR’, N.V. SIVKIN, N.A. ZINOVIEVA Federal Agency of Scientific Organizations, pos. <...> Dubrovitsy, Podolsk Region, Moscow Province, 142132 Russia, e-mail vijmikrob@mail.ru Acknowledgements: Supported by Russian Science Foundation, the project ¹ 15-16-00020 A b s t r a c t Inflammation of mammary glands of cows or mastitis is one of the most common infectious diseases of dairy cattle, which causes significant economic losses to livestock and affects the quality of dairy products. <...> This work was aimed at monitoring the presence of hemolytic streptococci and as the main causative agents of mastitis in the high producing dairy cows and identifying relationship between the milk somatic cell count (SCC) and the infection with . <...> Whole herd of clinically healthy Holstein cows of the Central region of Russia from first to seventh lactations ( = 345) were used for the milk sampling. <...> Depending on the presence of microorganisms in the milk, the cows were distributed between four groups: I — hemolytic streptococci and are detected; IV — both hemolytic streptococci and of antibiotic susceptibility profile of are not found; II — only hemolytic streptococci are detected; III — only are detected. <...> Determination isolates was carried out on a special medium using disco-diffusion method. <...> Determination of methicillin-resistant staphylococcus (MRSA) was carried out using the MRSA Alert w/swabs test («HiMedia Laboratories Pvt. Ltd», India). <...> The significance of differences was evaluated by Student’s t test. <...> It was found that only 22.0 % of clinically healthy cows did not contain studied forms of microorganisms in their milk, while in 78.0 % of them the presence of hemolytic streptococci and/or in milk was detected. <...> The higher levels of SCC in the milk of cows in group III with I, II <...>