A characteristic feature of high-yielding first-calf heifers is the intensity of metabolic processes occurring in their body. In their diets it is necessary to increase the concentration of metabolizable energy by reducing the level of fiber. This often negatively affects the cows’ digestion and milk production. At the same time, dairy cows, as ruminants, need a certain level of structural carbohydrates in their diets. This paper contains the results of research on the effect of different content of neutral detergent fiber and acid detergent fiber in the diets of first-calf heifers during early lactation on feed intake, digestibility and efficiency of energy use by the animal organism.

In the presented work, the composition of structural carbohydrates of corn silage was studied and their correlations with energy value were established. The research showed that between cellulose and lignin, as a complex included in the acid detergent fiber, the correlation relationship was high and negative – r = -0.71. It was found that the average lignin content in the selected samples was 6.97%±0.06, the correlation between the structural carbohydrates of ADF and lignin content was insignificant and weak – r = 0,15. Based on the obtained correlations, it may be concluded that with increasing lignin concentration with plant age, there is a quantitative decrease in cellulose content in the plant cell wall.

The modern level of fur farming industry development requires a fundamentally new approach to the issue of feeding fur-bearing animals. At present, fur farming scientists are actively searching for new sources of feed protein. In this regard, the possibilities of using various products of food, brewery, tannery and other industries are being studied. The purpose of the research presented in this article was to determine the effect of barley malt protein concentrate (BMPC) on the digestibility of nutrients in the feed of females for reproduction. The research has shown that the use of barley malt protein concentrate in the amount of 10 and 15% in mink diets does not reduce the digestibility of nutrients and gross energy and contributes to the increase of dry matter and protein digestibility coefficients. Due to its nutritional properties and chemical composition, it can become a worthy alternative to products of animal origin.

In industrial breeding, animals are exposed to conditions different from those of their natural habitat to which they have adapted through evolution. Many factors of this artificially created environment, feeding and housing, have a certain influence on the physiological condition of animals. This paper contains the materials of research aimed at studying the peculiarities of mink nutrition in the natural habitat and their adaptation in the conditions of cage breeding. It should be noted that experimental minks had certain dietary preferences. So, the American mink turned out to be more omnivorous, while the diet of the European mink was dominated by amphibians. The European mink also ate bird eggs, which was not the case with the American mink. The data obtained clearly show the traceability of seasonal changes in the food components of minks. So, in the winter period a gradual decrease in the diet of minks of fish from 33.4% to 0% was observed. It is found that this food plays an important role in the life of American mink in all seasons – its consumption ranged from 5.6 to 18.6 %.

High-yielding cows are particularly demanding in terms of nutrition and energy supply during the first 100 days of lactation. The use of protected fats in feeding is one of the ways to ensure the livestock livability and its high productivity. The article presents the materials of research, the purpose of which was to determine the effect of a complex energy feed based on dry protected fat as part of the diets for dairy cows with increased milk flow on milk productivity and biochemical status of the organism. The studies showed that inclusion of energy feed based on dry protected fat in the amount of 3% of the mass of compound feed in the diets of lactating cows with increased milk flow had a positive effect on the morpho-biochemical status of the organism and increased milk productivity by 8.1%.

Calf rearing technology is associated with the peculiarities of gastrointestinal tract development. The first six months of their life are characterized by the greatest intensity of growth, so at this age the requirements for nutritional adequacy are particularly high. Calves should receive the necessary amount of energy, complete protein, minerals, vitamins. This paper contains the materials of research, the purpose of which was to study the effectiveness of the use of crushed corn grain in feeding calves and determine the optimal rates of its inclusion in the diet. It has been established that the inclusion of crushed grain corn in the amount of 30 and 40% by weight of compound feed in the diet of young cattle at the age of 66-115 days has a positive effect on feed intake, which contributes to the intensive growth of animals, while reducing the feed costs and the cost of gain.

Obtaining healthy, well-developed young stock characterized by high growth rates is a key factor in cattle production. Milk and milk fodder consumed by the calf immediately after birth are of vital importance, as they contain all the necessary nutrients. However, it is not economically feasible to use them for a long time. An alternative to them are whole milk replacers, which are available in a very wide range. The paper contains the results of research on the physiological state and productivity of calves when using whole milk replacers with different composition of concentrate based on winter cress seeds. It was found that whole milk replacers with different composition of energy-rich concentrate based on winter cress oilseeds in the diet had a positive effect on feed intake, digestibility and utilization of nutrients, morpho-biochemical composition of blood, and productivity of young bulls. The use of the studied replacers made it possible to increase the average daily gain of calves by 5.4-9.5% with a decrease in feed costs by 3-11%.

Successful development of cattle breeding is impossible without rational use of fodder, balanced in all nutrients, minerals and biologically active substances. Protein nutrition plays an important role in feeding young cattle. Feed protein deficiency remains one of the main problems in animal breeding. Due to the high cost of imported protein feeds it is necessary to find their local analogs. One of the sources of protein can be oilseeds and products of their processing. The paper contains the materials of research aimed at studying the efficiency of feeding young cattle different doses of linseed cake. It was found that feeding young cattle with compound feed containing linseed cake in the amount of 20 and 25% by weight as a full-fledged substitute for sunflower meal made it possible to increase the average daily gain of animals by 3.6 and 4.9% with a decrease in feed costs by 3.0% and the cost of production by 3.45 and 1.48%.

In the system of full-fledged animal nutrition of paramount importance is the enrichment of feed with protein, which is necessary for the construction of cells and tissues, as well as for the nutrition of the body. Milk protein can be replaced with vegetable protein in calf diets as they grow, digestive organs are formed and their ability to digest feed changes. One of such sources of protein and fat in animal nutrition is rapeseed and products of its processing. The purpose of the research described in the article was to establish the effectiveness of feeding calves rapeseed cake and meal with a reduced amount of anti-nutritive substances. It was found that feeding young cattle with KR-1 compound feed containing rapeseed cake and meal in the amount of 15 % by weight made it possible to obtain average daily gains of calves at the level of 848-865 g with feed consumption of 2.99-2.52 feed units per 1 kg of gain. The cost of daily ration of young bulls of experimental groups was lower compared to the control group by 8 %. This is due to the fact that rapeseed fodder is cheaper. As a result, the cost of gain of young bulls receiving compound feed containing rapeseed cake and meal was lower by 2-5%, and the profit increased by 10% in comparison with the control group.

With the strengthening of the milk productivity potential of cows, the animals’ need for biologically active substances, including vitamins, increases significantly. Lactating cows need carotene, vitamins E and D in their feed. Vitamin concentrates in premixes predominantly fill the deficiency of these micronutrients in the diets of high-yielding animals. The aim of research was a comparative evaluation of the efficiency of using increased levels of vitamins A and E in the diets of Holstein dairy cows of Belarusian selection in dry, fresh and increased milk yield periods during mixed feeding. As a result of comparative evaluation, the advantage of moderately increased requirements for carotene (vitamin A) and vitamin E by 10% per 1 kg of dry matter of the diet for high-yielding dairy cows of Holstein breed of Belarusian selection was established. Application of these requirements can become one of the factors to increase biological full-value of diets.

High-yielding cows are most in need of vitamins, micronutrients and other biologically active substances as they build up their milk production potential. Rationing of carotene, vitamins E and D depends largely on the type of feeding, the ratio of nutrients in the diet and the level of animal performance. The article presents data on comparative evaluation of the effectiveness of increased levels of carotene (vitamin A) and vitamin E in the diets of high-yielding Holstein cows of Belarusian selection in the 2nd and 3rd third of lactation during mixed feeding. As a result of research, the advantage of moderately increased requirements for carotene (vitamin A) and vitamin E by 10% per 1 kg of dry matter of the diet for high-yielding dairy cows of Holstein breed of Belarusian selection has been established, application of which provides an increase in daily yield of milk of standardized 4% fat content in the 2nd and 3rd third of lactation (by 5.68 and 5.34%), higher milk protein yield (by 6.06 and 5.73%), greater stability of lactation over time (by 0.04%), and can become one of the factors to increase biological full-value of diets.

The growth of livestock production is largely constrained by the high cost of fodder and lack of feed protein. In this regard, it is necessary to search for new inexpensive feed resources rich in protein and able to reduce the cost of mixed fodder. Such sources can be food production wastes, which have high energy and biological activity, are harmless and hypoallergenic. The paper contains the results of research aimed at determining the efficiency of using malt sprouts as part of mixed fodder for fattening young cattle. It has been established that the use of mixed fodders containing 15 and 30% of malt sprouts in the feeding of young cattle positively affects its health.

Processing industry waste is an important source of protein. The use of protein components contained in them in the production of mixed fodders can reduce the grain component, thereby reducing their cost price. In our research we studied the efficiency of feeding malt sprouts as part of mixed fodder for preweaned calves. It was found that feeding calves KR-1 mixed fodder, including malt sprouts in the amount of 5% by weight instead of grain components, contributed to their live weight gain of 806 g per day, reducing the cost of feed for gain by 7.3% and the cost of live weight gain of calves by 10%.

A deficiency of complete protein results in a huge overconsumption of feed. This is an urgent problem in feeding farm animals and needs to be solved. Amino acids play an important role in providing vital functions of the organism with protein. The aim of research was to establish the need for limiting amino acids (lysine, methionine, threonine) and inclusion of their synthetic analogs in the composition of diets, contributing to increased productivity and efficiency of transformation of feed protein in the body of preweaned calves. It was found that the use of whole milk replacers containing synthetic amino acids in the diet of young calves aged 10-75 days made it possible to obtain live weight gain for the experiment at the level of 764-813 g and to reduce feed costs for gain by 1.7-6.6 %, metabolizable energy - 0.3-5.8 %, crude protein - 0.4-5.2 %.

The article analyzes the content of ¹³⁷Cs in the diets of groups of horses of similar sex and age in the Polesie State Radioecological Reserve (PSRER). It was found that the content of this radionuclide in forages (hay, oats, barley, triticale, barley straw, green mass of grasses of hayfields and pastures) did not exceed the permissible values established by hygienic standards, so they are suitable for feeding horses without restrictions. In the summer pasture season the content of ¹³⁷Cs in the muscle tissue of horses was within the range from 25 to 135 Bq/kg, which does not exceed the established standard and allows their realization without restrictions. In contrast to the summer pasture season, in the winter stall-feeding period this radionuclide accumulated in large quantities, therefore, before selling horses it is necessary to provide their temporary keeping on a “clean” diet with obligatory dosimetric control of ¹³⁷Cs content in their muscle tissue. As a result of the research, finishing horse stock management standards were developed to obtain horse meat with specific activity of ¹³⁷Cs not higher than 200 Bq/kg, providing optimization of conditions for breeding and feeding of horses.

At the present stage of pig breeding, due to the widespread breeding of meat genotypes, progressive technological methods of feeding and housing of animals are introduced. The development of the industry poses new challenges in assessing and developing standards of animal needs for metabolizable energy, essential amino acids and other nutrients and biologically active substances. The aim of the work was to study the effect of the concentration of metabolizable energy in the diet on the indicators of growth, tissue gain and the rate of protein retention in pigs. It was found that rationing of compound feed for young pigs with a live weight of 20-40 kg in terms of metabolizable energy, digestible lysine and other essential amino acids, balanced in accordance with the concept of “ideal protein”, made it possible to satisfy their physiological needs for these nutrients. Feeding animals with compound feed containing 13.8 MJ of metabolizable energy and 10 g/kg of digestible lysine provided 621 g of daily live weight gain at minimum feed consumption (1.44 kg/day).

Cow’s milk is the most nutrient-enriched human food containing all the necessary substances for growth, development and normal metabolism in the body. Given the ever-growing demand in the world and the Republic of Belarus for high-quality dairy products, the requirements to raw materials for their production are increasing, so the search for ways to obtain milk of high sanitary quality is relevant. Milk from the udder teat comes out almost sterile, but as it moves along the milking system, microflora is formed in it, the quantitative and qualitative composition of which changes depending on the conditions of storage and transportation of milk, which determines the sanitary and hygienic indicators of raw materials at its realization. In the course of research, a comprehensive study of treatment modes of milk hoses for pumping milk from the milking parlor to the cooling tank and from the cooling tank to the milk truck was carried out. Based on the assessment, generalization and analysis of the data obtained, the regulations establishing the list and sequence of technological operations on postmilking treatment of milk transfer lines, as well as the draft technical code of common practice of post-milking treatment of milk transfer lines, aimed at increasing the production of raw milk of "Extra" grade by sanitary and hygienic indicators, were developed.

The paper contains the results of studies on the vitamin and mineral composition of mutton obtained from the front, middle and back parts of carcasses of sheep of different genotypes bred in the Republic of Belarus. The mutton from sheep of the following genotypes was studied: wool-and-meat producing sheep (Precoce, Texel, Ile-de-France, Merinolandschaf, Suffolk, Lithuanian Black-headed), fur-and-meat producing sheep (Romanov sheep), meat-type sheep (Dorper). The difference in the content of vitamins (B1, B2, PP) and minerals (calcium, potassium, magnesium, iron, sodium) in the front, middle and back parts of carcasses of sheep of different genotypes was established. The studies were carried out in the laboratory of applied research for meat processing industry of the meat products technology department and in the production and testing laboratory of RUE “Institute of Meat and Dairy Industry”. The data on the content of vitamins and minerals in mutton obtained from the front, middle and back parts of carcasses of sheep of different genotypes can be used in the development of a variety of meat products with specified properties.

The paper contains the results of studies on the fatty acid composition of lipid fraction of mutton obtained from the front, middle and back parts of carcasses of sheep of different genotypes bred in the Republic of Belarus: Dorper, Precoce, Texel, Ilede-France, Merinolandschaf, Suffolk, Lithuanian Black-headed, Romanov sheep. The difference in the content of fat, polyunsaturated, monounsaturated and saturated fatty acids in the lipid fraction of the front, middle and back parts of carcasses of sheep of different genotypes was established. The lowest cholesterol content (mg/100 g) in the lipid fraction of the front part of carcass was observed in the Suffolk breed (53.1), and the highest – in the Merinolandschaf breed (84.8). In mutton of the middle part of carcass, the lowest cholesterol content was in the Ile-de-France breed (52.3), while the Dorper breed had the highest content (76.3). The lowest level of cholesterol in mutton of the back part of carcass was observed in the Merinolandschaf (32.0), and the highest – in the Romanov breed (78.9). Romanov, Precoce and Texel sheep breeds had an advantage in terms of the balance of fatty acid composition of the lipid fraction of the front, middle and back parts of carcasses, defined as the ratio of the total amount of polyunsaturated and monounsaturated fatty acids to saturated fatty acids. As for the biological efficiency of polyunsaturated fatty acids, defined as omega-6/omega-3 ratio, the least balanced was the lipid fraction of mutton from the front, middle and back parts of carcasses of Lithuanian Black-headed sheep.

The paper contains the results of studies on the content of essential amino acids in the protein of mutton obtained from the front, middle and back parts of carcasses of sheep of different genotypes bred in the Republic of Belarus: Dorper, Precoce, Texel, Ile-de-France, Merinolandschaf, Suffolk, Lithuanian Black-headed, Romanov sheep. Scientific studies were carried out in the laboratory of applied research for meat processing industry of the meat products technology department and in the production and testing laboratory of RUE “Institute of Meat and Dairy Industry”. It has been established that the protein of mutton from Romanov sheep, Suffolk, Merinolandschaf, Lithuanian Black-headed is characterized by high values of minimum scores (more than 100 %) and absence of essential amino acids limiting the nutritional value in all three parts of the carcass. In the Precoce sheep mutton protein, there is a limitation in methionine + cysteine (in the back part), in the Texel breed mutton protein - in leucine (in the middle part), in the Ile-de-France breed mutton protein - in methionine + cysteine (in the front part), in the Dorper breed mutton protein - in leucine and methionine+cysteine in the front and back parts, and in leucine, methionine+cysteine and phenylalanine+tyrosine in the middle part.

The level of performance of technological operations of machine milking is an important element of the work of specialists of commercial dairy farms and complexes, because it affects the productivity and health of animals. The important task of machine milking is to milk out the cow as quickly as possible and keep her mammary gland healthy. In order to identify the most frequent violations of the rules of machine milking, the timing of the work process of operators during milking of tied up cows into the milk pipe was carried out. As a result, the scale of quality assessment of the operator's fulfillment of modern provisions of technological regulations on the quality of technological operations of machine milking was developed. The responsibilities and the most important requirements to be imposed on the workers of this profession were defined.

Dairy cattle breeding is the most important branch of animal husbandry, which provides domestic milk processing plants with raw materials and the population with high-value food products. Recently, more and more attention has been paid to milk quality in milk production. Non-compliance with milking hygiene rules, lack of preventive measures and other components of the milk production process can negatively affect the quality of the resulting products. The article presents the results of a scientific work that studied the effect of hygiene products based on chlorhexidine and iodine on the state of the mammary gland and the quality of milk obtained in the conditions of Municipal Agricultural Unitary Enterprise “Experimental base “Maysk” of the Ivatsevichy District. As studies have shown, the greatest economic efficiency of milk production is achieved when using prophylactics and disinfectants based on chlorhexidine. This makes it possible to increase the profitability of dairy cattle breeding of the agricultural enterprise and significantly reduce the incidence of subclinical and clinical mastitis in animals - by 10.0 and 2.5 percentage points, respectively.

When developing technological elements for keeping calves in the early postnatal period, it is necessary to take into account a number of their biological features. Studies have determined the influence of the duration of keeping calves in individual houses on their productivity, behavior and comfort. Thus, when increasing the duration of keeping calves in individual houses up to 30 and 45-90 days, the daily live weight gain increased for the first three months of life by 4.9 and 5.5-7.0 %, respectively, compared to calves with 20-day duration of individual keeping in houses. Calves transferred to group sections at the age of 30-45 days adapted relatively quickly to external conditions, moved actively, and stood on their feet for less time. This makes it possible to create more comfortable conditions for keeping young calves that meet their biological needs. It is found that increasing the floor area up to 1.8 m²/head allows creating more comfortable conditions for loose-housed replacement heifers of 3-6 months of age, providing an increase in their daily live weight gain by 4.6 %.

To reduce losses in pig production at all stages of growth, it is necessary to level out the main causes of stress reactions in animals. This will increase the productivity and livability of pigs by improving the comfort of housing conditions. As part of the research, the stress situations among breeding stock of pigs were analyzed, the main parameters of influence on animals by manipulation materials, as well as the use of classical music were established. The scale of species-specific behavioral patterns of pigs when using video surveillance system was developed. The data obtained in the process of research will make it possible to optimize the environment of animals at modern pig-breeding enterprises, adapting it to the maximum extent possible to the biological features of the pigs’ organism, to prevent in time the influence of stresses and, thus, to increase the vitality of pigs.

A cow should spend at least 12-14 hours a day lying down. During this time the blood circulates more actively in the udder, milk production is more intensive and at the same time the ligaments, joints and hooves are relieved and rested. Optimal lying time is achieved only with sufficient comfort, which can be provided by the box floor covering. The article presents the results of assessing the comfort of cows kept on various rubber coverings (monolithic rubber slabs of foreign manufacture previously used on the farm and rubber-cord slabs with the size of 1930×1230×18 produced by JSC “Belshina” according to TS 38.14762133-19-9) and their influence on physiological state of animals. It has been established that the use of rubber-cord slabs produced by JSC “Belshina” contributes to the creation of a warmer, drier and cleaner den, which affects the duration of rest of animals. Keeping animals in boxes with a covering made of these slabs does not have an adverse effect on the animal skin temperature and does not cause disturbances in the clinical and physiological state of cows or their diseases.

Industrial technologies in pig breeding along with increasing the efficiency of production create a significant environmental burden due to the disposal of manure effluents, the volume of which increases when pigs are kept without bedding. One of the effective measures to minimize environmental pollution is the use of self-draining batch manure removal system. The main principle of its efficiency is the availability of process water, providing the required rheological properties of the effluent, in the storage tanks. Due to the fact that manure removal is one of the most complex and labor-intensive processes in the whole technological chain of production, requiring the expenditure of significant amounts of water, techniques have been developed to reduce water consumption for cleaning the premises for growing-finishing and fattening pigs, consisting in reducing the layer of water cushion at the bottom of the baths by 30-50%. In the process of approbation it was established that the application of the developed methods provided maintenance of a favorable microclimate in the room, increasing the production abilities of livestock. The total economic effect was obtained, which amounted to 8.09 rubles or 2.53 $ (in 2023 prices) per one grown head of young pigs.

In commercial poultry production, producers are always looking for ways to improve efficiency in raising poultry and producing meat products. One such way is to include feed additives in the diet. The studies showed that the use of feed additive “Agromix-Bio Plus” during the period of growing broiler chickens for meat production contributed to an increase in live weight at slaughter age of broiler chickens by 4.9 %, poultry stock livability – by 0.85 p.p., grade 1 carcass yield, with a simultaneous decrease in grade 2 carcass yield by 0.6 percentage points.