Deficiency of key minerals adversely affects animal productivity and provokes the occurrence of diseases associated with micronutrient deficiencies. This emphasizes the importance of including organic forms of micronutrients in the cattle diet. Such organic complexes increase the availability of essential substances, strengthening the health of animals and contributing to the growth of their productivity. The paper presents the results of research on the efficiency of using organic chromium in feeding young cattle aged 6-9 months. It was found that feeding young bulls at the age of 6-9 months with compound feed containing Biopromis Chromium picolinate had a positive effect on digestive processes in the rumen and on the blood composition of animals, which contributed to an increase in average daily live weight gain by 2.2-5.0 % with a decrease in feed costs by 1.63-3.52%. Based on the results obtained, it can be noted that the use of concentrates with the addition of organic chromium compounds is an effective way to increase the productivity of cattle.

   The paper contains the results of research aimed at determining the dynamics of semen production and concentration of amino acids in the semen of stud bulls with the peptide-amino acid chelated product “PAD-3” included in the diet.

   As a result of the conducted experiment it has been established that the use of the studied product in feeding of stud bulls in the amount of 2 and 3 % of the weight of concentrated compound feed allows increasing the volume of ejaculate by 6.4 and 6.7 %, sperm activity – by 2.5 and 1.3 %, sperm concentration in ejaculate – by 7.6 and 6.8 %, semen fertilizing capacity – by 6.1 and 6.3 p. p. and the concentration of non-essential and essential amino acids in semen.

   Fiber makes up a major part of the diet of ruminants, so studying the nutritional value of feed and improving diets in terms of the content and ratio of structural carbohydrates is relevant for the production of livestock products.

   The purpose of the study, the results of which are presented in this paper, was to study the balance and utilization of nitrogen, as well as ruminal digestion of first-calf heifers during early lactation depending on the content of structural carbohydrates in the diet.

   During the experiments it was found that the level of structural carbohydrates in the diet of first-calf heifers influenced dry matter intake. The optimal levels of structural carbohydrates in the diet of lactating cows during early lactation (30.7-32.6 % of NDF and 21.5-21.9 % of ADF) were determined, promoting more intensive ruminal digestion, expressed in maintaining the optimal pH value of the rumen at a level of 6.65-6.61 units, in improving the digestion of structural carbohydrates of plant feeds with an increase in the formation of end metabolite products (VFA), a decrease in the ammo-
nia content and an increase in milk productivity.

   This paper contains the materials of research aimed at studying the cleavability of neutral detergent fiber in haylage depending on its quantitative content.

   In the process of studying the composition of structural carbohydrates in preserved grass fodders, it has been found that when they accumulate in the dry matter of green mass for silage and haylage, the total content of metabolizable energy and feed units decreases, which in turn reduces the productive effect of the fodder. When determining the regularity of kinetics of neutral detergent fiber in legume-grass preserved fodders in the rumen of ruminants with the establishment of their cleavability, it has been found that, as in grass haylage, the cleavability of neutral detergent fiber has a strong inverse relationship and depends on its total content in the dry matter of the fodder.

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   Sugar sorghum is an indispensable crop in solving the problem of fodder shortage in mid-summer and autumn, it is characterized by high and stable yield, good feeding qualities, technological efficiency of conservation and storage, therefore, the study of the use of sugar sorghum silage in cattle diets is relevant.

   This paper contains the materials of research aimed at studying the milk productivity of lactating cows fed with sugar sorghum silage as part of the diet.

   It was found that the inclusion of sugar sorghum silage in the diet of animals contributed to an increase in the average daily milk yield by 2.0 %, and when converted to milk with basic fat content, productivity was higher by 3.6 % and amounted to 19.45 kg of milk per animal per day compared to the group of animals fed with corn silage as part of their diet.

   The paper contains the results of research on the effectiveness of using the energy feed concentrate “Energopak” in the diets of lactating cows during the transition period. It has been established that its use in the amount of 300 g per head per day contributes to improved quality of colostrum and milk productivity of cows, expressed in an increase in dry matter in colostrum by 0.50-5.83 percentage points, protein mass fraction – by 0.11-5.20, fat mass fraction – by 0.4-1.0, lactose mass fraction – by 0.13-0.30 p. p., immunoglobulins – by 2.52-18.74 g/l, average daily milk yield on the 6^th and 20^th days of lactation – by 6.3 and 7.9%, respectively.

   The cattle feeding efficiency is determined by the type of diets, formulation of compound feeds and feed additives. Balanced feeding during the dry period ensures the cow health improvement, preservation of reproductive functions, and good health of newborn calves.

   The paper contains the results of research aimed at determining the efficiency of using the “LaktECO” DRY” premix in the feeding of dry cows.

   It was found that optimization of feeding of pregnant dry cows led to an increase in animal productivity. The live weight of calves in the experimental groups was 1.2-1.3 kg higher than that of their counterparts in the control group. It proves that the use of the premix had a positive effect on the intrauterine development of animals. The relative gain in all studied groups was also rather high. Thus, the use of the “LaktECO” DRY” premix in the feeding of dry cows makes the product more competitive and promotes the efficiency of dairy cattle breeding.

   The paper contains the results of research aimed at studying the effect of feeding compound feed with the use of chemical treatment of protein concentrates on the productivity indicators of young cattle. It was found that feeding young cattle aged 6-12 months with compound feed containing high-protein feed treated with organic acids increased the absolute live weight gain by 7.9-9.0 % compared to the control group. The increase in productivity contributed to effective transformation of feed nutrients into products. Feed conversion rate decreased by 8.71-7.86 %.

   The paper contains the results of statistical analysis of the indicators of structural carbohydrates in grass forages conserved by agro-industrial enterprises of Brest region in 2021-2024. Based on the analysis of 2836 samples, reliable mathematical models of dependence of ADF on NDF and CF; CF on ADF in corn silage, as well as in grass and grass-and-legume haylage were established. The models can be used in routine laboratory work as a complementary method of analysis. Strong dependence of ADF on CF; CF on ADF in legume-grass haylages and alfalfa haylages in a single form was established, however, the approximation error > 10 indicates the impossibility of practical application of these models and requires additional research. Uniformity of botanical composition of the batch of samples is one of the key conditions for creating a mathematical model of dependence. When forming a batch of samples of alfalfa haylage that was homogeneous in terms of botanical composition, and reducing the number of samples in it by 60 % in relation to the total number of legume and legume-grass haylages, comparable coefficients of determination were obtained.

   One of the promising trends in modern practice of feeding farm animals is the use of organic compounds of micronutrients, which, due to their high bioavailability and digestibility, have a positive effect on the quality of the resulting products, strengthen the immune system and help reduce morbidity. However, the search for optimal dosages and the development of their schemes in cattle diets always remain a topical subject of research.

   The paper contains the materials of research aimed at studying the effectiveness of using cobalt sulfate and cobalt acetate in feeding young cattle aged 12-18 months.

   It has been found that the replacement of mineral cobalt with cobalt acetate in the diet of young bulls aged 12-18 months leads to a decrease in the concentration of volatile fatty acids in the rumen by 6.7 %. The use of concentrates with the addition of organic compounds of cobalt contributes to an increase in average daily live weight gain of experimental animals by 4.0 %, while reducing the feed consumption per unit of gain by 3.6 %.

   In recent years, there has been an increasing interest in the Republic of Belarus in the use of various feeds and additives that can significantly affect the metabolism and productivity of animals. One of such feeds is peas, characterized by a rich content of proteins, vitamins and minerals. Production of this crop is growing every year and its quality is improving. This opens up new opportunities for increasing its use in compound feeds for young cattle. The paper contains the results of research aimed at studying the features of metabolism and productivity of young cattle fed different doses of peas. In the course of the research, both quantitative and qualitative changes in the organism of animals were considered, their productivity indicators were analyzed. It was found that the inclusion of ground pea grain in the amount of 15 and 20 % by weight of compound feed in the diet of young cattle at the age of 10-75 days had a positive effect on feed intake and intensity of metabolic processes in the body, increased the intensity of animal growth, while reducing the cost of production. This allows us to draw conclusions about the feasibility of using peas in the diet.

   Adequate feeding, providing animals with the necessary amount and ratio of protein and energy, is one of the key factors for achieving maximum yield with minimum production costs. To properly and most accurately balance diets for nutrients, a variety of ingredients must be used, including expensive imported products such as sunflower and soybean meal. Therefore, it is necessary to look for alternative, more affordable sources of protein, in particular flaxseed cake, which contains a complex of important organic substances and essential amino acids, and has a high nutritional value.

   The paper presents the materials of the work aimed at studying the effect of feeding young cattle with linen flaxseed cake on metabolic processes in the body and the feed-use efficiency.

   It was found that feeding young cattle with experimental compound feed containing linen flaxseed cake in the amount of 15 %, 20 and 25 % by weight as a full-fledged substitute for sunflower meal made it possible to get average daily live weight gain of young animals at the level of 926 g, 994 and 1021 g (control value was 964 g). Inclusion of linen flaxseed cake in the amount of 15% by weight of compound feed provides a reduction in the weight gain of animals by 3.9% (926 g) relative to the control value (964 g).

   Red dairy cows demonstrate high productivity and improved milk characteristics, which is why this breed is in demand in dairy farming in the Republic of Belarus. Developing optimal rations for animals of this breed will increase the efficiency of milk production, reduce the risk of disease, and increase the profitability of enterprises in the industry.

   The aim of the study was to comprehensively investigate the effectiveness of increased levels of minerals (calcium, phosphorus, magnesium, sulfur) in the feeding of Red dairy cows of Belarusian selection during various physiological
periods of the animals’ lives (dry period, increasing the milk yield) using total mixed rations.

   The studies showed that the use of moderately increased requirements for calcium, phosphorus, magnesium, and sulfur by 2-5% per 1 kg of dry matter of the diet ensured higher body weight gain and the production of calves with increased growth capacity. There was also an increase in daily yield of milk of standardized 4 % fat content in milk yield periods by 3.57 % and 6.15 %, respectively, as well as higher milk protein yield and greater lactation stability over time, indicating an increase in the biological full-value of rations.

   The milk of red dairy cows is of high quality and significantly surpasses other breeds in fat and protein content, which is why these animals began to be used in dairy farming in the Republic of Belarus. However, the current feeding standards in the country do not meet the needs of cattle of this breed in basic nutrients and minerals, so it became necessary to develop them.

   The aim of the presented work was to optimize calcium, phosphorus, magnesium and sulfur requirements for red dairy cows in the second and third periods of lactation.

   As a result of research, the advantage of moderately increased requirements for calcium, phosphorus, magnesium and sulfur by 2-5 % per 1 kg of dry matter of the diet for cows of the studied breed has been established, application of which provides an increase in daily yield of milk of standardized 4 % fat content in the main and final periods of lactation by 6.47 and 6.50 %, respectively, higher milk protein yield, greater stability of lactation over time, activation of function of hematopoietic organs, which can become one of the factors to increase biological full-value of diets.

   This paper contains the results of research aimed at determining the effectiveness of the influence of feeding system elements on zootechnical parameters and ruminal digestion of cows.

   The state of animal health and parameters of the internal environment of the rumen in the 2^nd phase of the dry period were also studied. The research showed that the studied elements of the feeding system ensured an increase in the digestibility of the main nutrients of the diet by 1.4-2.1 percentage points. Their positive effect on the stability of the rumen microbiome composition, mainly represented by cellulolytic bacteria, the number of which increased by 5.8-11.5 %, was also established.

   Ensuring radiological safety of milk is a priority task in the current animal breeding of our country, which is due to strict requirements for product quality in the conditions of the modern economy.

   Indoor maintenance of cattle results in a deficiency of metabolizable energy and minerals in the diets, and vitamins A and E in the organism, while vitamin D requirement increases. In this regard, the aim of the research was to study the influence of mineral composition and vitamin D content in the diet on the transfer of ⁹⁰Sr into milk.

   In the course of radiometric surveys of specific activity of ⁹⁰Sr in feeds that formed the basis of the diet of lactating cows, the parameters of transfer of this radionuclide from the diet into milk were studied. Based on the research results, proposals were formed to optimize the mineral composition and structure of diets of cows kept in agricultural enterprises of the Gomel region, located in the territory of radioactive contamination.

   Noise pollution in livestock buildings is a modern-day, pressing and understudied problem. The sources of noise are various feed preparation mechanisms, milking machines, scraper units, mobile transport used for feed distribution and manure removal, as well as the animals themselves.

   This paper contains the results of research aimed at studying the level of noise impact during the implementation of the main technological processes when keeping cows at commercial dairy farms and complexes.

   It has been found that noise levels exceeding the permissible threshold (70 dB) are considered stressful for dairy cattle and can cause negative behavioral reactions in animals. Identification of possible noise sources arising during the operation of cattle housing facilities allows workers at dairy farms and complexes to minimize dangerous situations and accidents associated with uncontrolled behavior of cows when exposed to noise.

   Recombinant lactoferrin produced by the mammary gland of transgenic goats corresponds to the native protein in its structure and functional activity, retaining all its biological properties. Long-term studies have established some effect of genetic modification and seasonal variations on the composition of milk of transgenic animals. These factors must be considered in the long-term housing of a dairy herd and the development of technologies for processing milk with certain biotechnological properties. This paper contains the results of analyzing the seasonal dynamics of recombinant lactoferrin content in the milk of transgenic goats during a three-year monitoring period. In the course of studies conducted during 2022-2024, pronounced seasonal variations with a tendency to decrease the protein level in the spring-summer period were established. In 2022, the lowest variability of indicators was observed (2.8-3.0 g/l) with minimal deviations compared to 2023 and 2024. The identified interseasonal differences indicate the influence of the season on the synthesis of rLF.

   Along with feeding, the determining factor affecting the productivity of sows is the supply of clean, good-quality drinking water at the right temperature and in the right quantity at all stages of the reproductive cycle. When keeping sows in an industrial facility, significant amounts of water are consumed for technological needs. Overconsumption of water leads to an increase in the cost of manure disposal, and the ecological load due to the operation of a pig farming enterprise increases.

   In this regard, the issues of reducing water consumption for technological needs, which exceeds the needs for watering pigs, are of particular relevance, which has become the purpose of the scientific work.

   In the course of the research, water consumption standards for liquid type of feeding in heavily pregnant and lactating sows by seasons for drinking and performing technological operations in an industrial-type enterprise were established. The use of these standards made it possible to maintain a favorable microclimate in the farrowing section, as well as to save 5,964 liters of water (for 1 cycle of housing for 35 days) used for manure removal, which reduced the cost of animal housing, including the cost of water supply, processing, storage, transportation and disposal of manure effluent.

   Animal welfare implies the creation by humans of a set of conditions that ensure the satisfaction of all biological needs of the organism and contribute to the full development of its genetic potential. In this regard, we have analyzed the pig environment comfort level in the conditions of industrial pig breeding complex, defining the human role in the creation of optimal animal housing conditions. Studies conducted in the suckling sow sectors have confirmed the importance of maintaining optimal microclimatic parameters. In particular, for sows due to farrow it is necessary to ensure an air temperature of at least 22°С. For newborn piglets, it is necessary to maintain the temperature in the range of 30-35°С, by the end of the suckling period this indicator should be 24°С, and before weaning – 28 °С. When studying the operator’s actions, it has been found that his presence at the moment of farrowing increases the livability of piglets during the most critical period of suckling on the 3-5^th day after the birth of piglets on average by 2-3 %.

   Nowadays, modernization of existing and construction of new farms and complexes for milk and beef production is becoming the main direction of intensification of livestock production, so making an optimal decision regarding the expediency of reconstruction or construction of new livestock facilities is possible only on the basis of a detailed comparative analysis of elements reflecting the economic, technological and production efficiency of each of the objects of similar capacity.

   The paper contains the results of research aimed at developing an integral indicator for assessing space-planning and technological solutions in the modernization, reconstruction and new construction of farms and complexes for milk production.

   In the course of the work, the main approaches to the evaluation and selection of the most effective for implementation in the production process option of the combination of space-planning and technological solutions in the modernization or reconstruction of farms and complexes for milk production are determined.