Livestock and poultry diseases occurring due to mineral or vitamin deficiencies are widely reported and belong to the factors restraining the development of livestock industry. Almost until the 90s of the last century, the conditions associated with trace element deficiency were prevented and treated using inorganic compounds. In recent decades, scientists have synthesized chelate metal compounds using organic carriers, determining the high bioavailability of these compounds and the efficiency that repeatedly exceeds the efficiency of inorganic compounds. Amino acids are preferably used as organic carriers. In addition to their main function, i.e. replenishing the trace element deficiency, chelate compounds increase the enzymatic activity, the functional activity of the immune system, and are also able to enhance the absorption of other trace elements, showing a synergistic effect. Due to the immunostimulatory activity resulting from increase in the content of sialic acids, properdin, ceruloplasmin, gamma globulin protein fraction, the metal chelates (copper, cobalt, iodine) can be used as immune response modulators. Iron chelate compounds are used for therapy and prevention of iron deficiency anemias not only in veterinary, but also in human medicine. This paper is based on data analysis of Scopus, CyberLeninka, PubMed, RSCI and other databases and systematizes scientific knowledge on the problem of designing and synthesizing metal chelate compounds using organic carriers. The scientific rationale is given for the use of amino acids and organic acids as organic carriers of metal, vitamin and other compounds. The mechanism of biological action of chelate compounds and the pathogenesis of trace element deficiencies in animals are considered, while the advantages of chelate compound use in microelementoses therapy and prevention are specified.

Relevance . Today the scientific community all around the world is showing significant interest to the study of endogenous intoxication syndrome in the body. The article presents the results of assessing the level of endogenous intoxication in diseases of the liver of cattle by the concentration of molecules of medium mass in the blood serum. Methods . Two groups of cows were formed, 50 animals each: 1 — healthy livestock; 2 — with liver pathology. The state of the liver in cows was assessed by the clinical status, the boundaries of the liver and its sensitivity, biochemical blood tests and ultrasound diagnostics of the hepatobiliary system. The level of endogenous intoxication in cows was studied using two MMM fractions at wavelengths = 254 nm (MMM 254) and = 280 nm (MMM 280). Results . The highest values of markers of endotoxicosis in the blood were observed in cows with hepatitis. Thus, a significant difference in MMM 254 (toxic fraction) with healthy animals in this subgroup was 1.8 times, changes in the MMM 280 fraction (fraction containing aromatic amino acids) were less pronounced — there wasan increase of 25.4%. The level of MMM 280 in the blood of cows with hepatosis did not significantly change in relation to the data of healthy livestock, at the trend level, an increase of 10.1% was observed. The level of MMM 254 at the same time significantly increased by 1.5 times. The calculation of IR 280/254 in cows with hepatopathology revealed a decrease in the index with maximum changes in animals with hepatitis; relative to healthy livestock, there was a difference of 30.4% (hepatitis) and 25.3% (hepatosis).

IntroductionT he main trend in the development of modern society is an increase in the range and volume of production of specialized food products.These products are aimed at correcting the nutritional status, increasing stress resistance at a high rate of life, preventing social diseases, and increasing the active life expectancy of a person (Anisimova et al.,

The article presents the results of assessing changes in biochemical parameters and the concentration of molecules of medium mass in the blood of cows with mycotoxicosis during treatment. It has been determined that mycotoxicosis in cows, caused by the combined intake of T-2 toxin and aflatoxin B1, is characterized by changes in the biochemical status of the animal organism in violation of protein, carbohydrate and lipid metabolism, as well as the development of hepatic-renal failure. In case of mycotoxicosis an increase in the level of endogenous intoxication in the body of cows was registered with a dominant MMM 254 in the blood and a less significant increase in MMM 280. The dynamics of the clinical status and blood parameters of cows during the treatment of mycotoxicosis shows that the determination of the concentration of MMM in the blood of animals is quite justified for determining the direction (progression or relief) of the course of the disease and allows evaluating the effectiveness of treatment.

The article describes characteristics of milk productivity of meat cow breeds in the south of Tyumen region. The breeds under study (Hereford, Charolais, Limousine, Salers and Obrak) are compared. The level of milk productivity in Hereford, Obrak and Salers cows is higher than that of limousine and Charolais. The average daily productivity of Hereford cows was 4.97 kg, Obrak cows – 4.89 kg, Salers cows – 4.77 kg, limousines cows – 4.51 kg and Charolais cows – 4.44 kg. Hereford cows had the most nutritious milk – 3103.8 J, milk produced by Obrak and Salers cows had a nutritional value which was lower by 1.0 %, by limousine cows – by 2.8 %, by Charolais cows – by 4.3 %. Milk productivity tends to increase with age and different generations. Thus, Charolais cows had the highest milk yield, and the Limousine cows had the lowest milk yield. Unique and time-consuming data that can be used by all agricultural enterprises are presented.

Estrous synchronization allows monitoring the estruation onset and ovulation in the cows or heifers with normal estrous cycles. For dairy cattle, grouping the cows with regular estrous cycles facilitates artificial insemination and accelerates genetic improvement. The number of days needed for artificial insemination is significantly reduced. Therefore, the authors studied the efficacy of the combined use of the gonadotropin-releasing hormone, prostaglandin, and progesterone preparations for stimulating estruation has been studied. The combined use of hormones and prostaglandins is effective in stimulating the arousal stage in cows and heifers. The authors developed a complex scheme of induction (stimulation) and synchronization of reproductive function in cows and heifers. Experimental testing of this technique was carried out in 2017-2019 based on the "Russia" CJSC in the Kanevsky district (Russia). 106 animals were examined. The analysis of literary sources shows that the yellow body of ovary hormones has a specific effect on the genitals. The results of this study were showed that during inflammatory processes in the genitals of cows, the follicles undergo luteinization and can transform into the persistent yellow body, thus causing the absence of the estrous cycles. The studied was confirmed that one-time diagnostics during rectal examination does not provide grounds for distinguishing the persistent yellow body from the yellow body of the cycle. For determining the persistent yellow body, a two-time study in the intervals of three to four weeks is required. Prolonged infertility caused by the progesterone hormone leads to a shortfall in calves and milk. Therefore, the persistent yellow body treatment should be performed in time.