In a bacteriological study of 412 samples of the udder secretion of sick cows with mastitis, 121 cultures of microorganisms of 15 species were isolated, which were represented in 54.9% of cases by gram-positive cocci, the remaining 45.1% by representatives of the Enterobacteriaceae and Ps. aeruginosa, staphylococci prevailed - 28.6%, streptococci - 22.6%, enterococci - 19.2%. When the incidence of cows with mastitis is more than 30%, the microflora was isolated from 81.8% of udder secretion samples, including pathogenic microflora (Staph. aureus, E. coli) - in 32.7% of cases, conditionally pathogenic (C. diversus, Ent. faecalis) - 23.6% and 20.0% - saprophytic microflora (Staph. saprophyticus, Staph. epidermidis, Ent. aerogenes, Ps. aeruginosa) and fungi (Сandida) - 5.5%. The results of the study showed that in clinically healthy lactating cows, the bactericidal activity of the udder skin varies depending on the functional state of the mammary gland and has a maximum value of 91.8 ± 2.0% in the first week after birth, decreasing to 87.8 ± 2 by the middle of lactation. .4% and becomes minimal during the launch period - 79.7±2.3%. The change in the bactericidal activity of the skin of the udder teats is associated with the state of other non-specific factors of local protection, in particular, the titer of lysozyme M and the level of somatic cells.

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Reproduction and culling of productive animals are the main factors that affect the number of cows in a herd. Timely determination of fertility in replacement heifers with subsequent culling of problem heifers will help reduce direct economic losses in breeding dairy cattle. When making a diagnosis, veterinarians should exclude all forms of temporary or permanent infertility, including Congenital anomalies (infantilism, freemartinism, deformities, etc.).In order to establish the hormonal status of heifers-freemartin in the blood serum, the concentration of sex hormones (progesterone, estradiol-17ᵦ, and testosterone) and anti-Müllerian hormone (AMH) was determined.Studies of the level of AMH using an enzyme-linked immunosorbent assay in blood serum have proven the possibility of early assessment of fertility in heifers. This method will allow early culling of Freemartin heifers from a productive herd. The study of AMH levels showed that its amount directly correlates with fertility in cattle, regardless of the period of the estrous cycle. When the concentration of AMH in the blood serum is below 100 pg / ml, heifers are not capable of fruitful insemination, while a high level of anti-Müllerian hormone (more than 380 ng / ml) makes it possible to successfully fertilize animals on the first attempt. All clinically healthy replacements obtained during a single pregnancy were successfully inseminated. At low concentrations of anti-Müllerian hormone, Freemartin heifers were sterile, even after hormonal stimulation (Co-Synx) and sperm doses were administered without clinical manifestation of sexual desire.The introduction of testing for the level of AMH by the ELISA method in the mandatory gynecological clinical examination of cattle in livestock enterprises is expedient and effective.

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Soils in the Vladimir region are poorly represented by mobile forms of cobalt and zinc, below average they are provided with boron and manganese. Accordingly, there is a need for the administration of preparations containing trace elements to replenish deficient feed rations. The use of the preparation «Polysalts of microelements» leads to an increase in the level of copper, zinc, cobalt and manganese in the blood serum of cattle, restoring the physiological norm. The optimal dose of the preparation «Polysalts of microelements» has been selected. It is 300 mg daily for 20–30 days in infertile animals, or daily at a dose of 270–300 mg in the last third of pregnancy before the expected calving When using «Polysalt of microelements» for 30 days at a dose of 300 mg, 100% of the cows came to hunt. The period from calving to full libido averaged 30,9±2,39 days; the service period was 79,5±2,47 days, and the insemination index was 1,6±0,14.