Belarusian Large White breed is the most widespread among planned pig breeds in the Republic of Belarus. Currently, using methods of molecular biology, information about genetic markers and their correlation with economically useful traits, it is possible to conduct selection process in pig breeding at a qualitatively new level. In this regard, research was carried out at the breeding enterprise of the agricultural branch of Zadneprovsky SGC Orshanskiy KHP OJSC in the Vitebsk region in order to develop a system of selection and genetic measures for use of Belarusian Large White pigs in linear breeding based on DNA technologies. Based on polymorphism of genes-markers of performance traits, the genetic potential of lines and related groups of boars of Belarusian Large White breed has been determined. Based on analysis of the research results, the genetic profiles of lines and related groups of pigs of Belarusian Large White breed at the base enterprise of Zadneprovsky SGC were constructed.

In the dynamics of 2002-2019, a slight increase in the number of cattle of the Ukrainian Gray breed has been determined against the background of a slight increase in milk yield of cows with the first calving and yield of calves per 100 cows, as well as decrease in the growth rate of young animals. The purebred livestock of the Ukrainian Gray breed belongs to two genealogical lines: Shamrin XY-141 and Petushok 191-Y and is kept only in two breeding herds of Ukraine. A comparative assessment of body weight of heifers at the age of 210 days and 8 months indicates the advantage of young stock of Shamrin XY-141 line over the Petushok 191-Y line by 4.7 kg and 1.6 kg, respectively. Further, the advantage was on the side of the representatives of Petushok 191-Y line, but with no statistically significant difference between them. The body weight variation ratio of heifers of Petushok 191-Y line during rearing made 6.06-13.81%, and Shamrin XY-41 - 7.11-13.88%, indicating insignificant, but still possibility of increasing the trait by breeding method. Crossbreed heifers were inferior to purebred in terms of body weight and weight gain during rearing, indicating inappropriateness of interbreed selection of animals of the local population with modern breeds of beef cattle.

Indicators of bulls’ semen motility were studied at all stages of preparation for in vitro fertilization. In the process of preparing semen for fertilization, when passing through all stages, there was a clear tendency for decrease in the average total motility of semen (by 14.2%), motility of sperm cells with rectilinear translational movement (by 19.0%), distance of the path curve (by 12.6%), distance of the average path (by 5.4%), distance of the straight path (by 3.2%), curvilinear speed (by 26.0%), the average speed of movement along the trajectory (by 11.7%); rectilinear movement speed (by 7.9%) and head oscillation frequency (by 5.7%). At the same time, indicators of linearity (by 9.8%), straightness (by 6.2%) and oscillations (by 10.2%) increased, and the values of the amplitude of the lateral head displacement did not change significantly.

When implementing measures prescribed in the Republican Program for Development of Sheep Breeding for 2013-2015 and in the Package of Measures for Development of Sheep Breeding in the Republic of Belarus for 2019-2026, the number of sheep increased. Thus, according to Belstat data, as of January 1, 2021, the increase in agricultural organizations made 6.2%, in peasant (farm) households - 1.7%, in population’s households the livestock decreased by 1.7%. It has been determined during the research that Prekos breed is bred at the Vostok Combine plant OJSC of Gomel region, which was awarded the status of a “Pedigree sheep breeding reproducer” in 2015. Researchers, together with specialists from the Gomel breeding enterprise, determined the feasibility of its use in further selection and breeding work to improve the breeding traits, primarily exterior-and-constitutional, as well as to increase body weight of hybrid sheep. To improve the breed and performance traits of animals, schemes have been developed for obtaining sheep bred at the enterprise.

The paper presents the results of work with purpose to establish the efficiency of fertilization in in vitro culture of oocytes of cattle with semen divided by gender. In total, 1804 oocytes were fertilized: 770 with ordinary semen and 1034 with divided by gender. 583 blastocysts were obtained. The cleavage level was almost the same and made 91.9% when using ordinary semen, and 91.3% when using semen with certain gender. The output of blastocysts during fertilization with certain gender semen made 29.9% of the number of fertilized oocytes and 32.7% of the number of cleaving embryos, which turned out to be 5.7 and 6.0 p.p. lower compared to ordinary semen, respectively.

The embryoproductivity of donors is of great importance in increasing efficiency of secondary reproductive technologies in vivo and in vitro . Optimizing use of donors can play an important role in raising its level. In the course of the research, the efficiency of donors used for obtaining embryos with in vivo and in vitro technologies has been studied. A total of 31 donors were used. There were 1031 aspirations (33.3 per donor) and 96 extractions (3.1 per donor). 803 in vitro embryos were obtained (27.8 per donor and 0.9 per aspiration) and 601 in vivo embryos (19.4 per donor and 6.2 per extraction). In the course of the research, individual differences in embryoproductivity of donors were noted. So, in 16.1% of animals (5 animals: 2 in vitro and 3 in vivo ) embryos were not obtained, in 22.6% (7 animals) equally high results were obtained both in vitro and in vivo : over 1 embryo per aspiration and over 5 embryos per extraction, 22.6% (7 animals) obtained higher results in vivo , and 22.6% (7 animals) in vitro . Five animals (16.1%) showed approximately the same results both in vivo and in vitro , with average values. It has been also determined that, in terms of monthly embryo productivity of in vitro technology, its efficiency exceeded the traditional technology of transplantation ( in vivo ) over three times - 7.0 embryos versus 2.2, although the yield of embryos per extraction was significantly higher compared to the yield of embryos per aspiration - 6.2 versus 0.9.

The paper presents materials of research with purpose to determine population belonging of boars of Belarusian black-and-white breed based on microsatellite analysis. Genetic testing was carried out on pigs of the Belarusian black-and-white breed, bred at breeding farm CAUE Plemzavod Lenino, SGC Vikhra and SGC Zarechye OJSC. Based on the research carried out, it has been determined that all the boars of Zarechye SGC were close in origin to the boars of Lenino breeding farm. Coincidence of microsatellite analysis results of boars of two lines of Slutsk and Zaston with boars of those lines from the Lenino breeding farm indicates their purebredity and common origin.

As a result of the research, it has been determined that semen production rates were 3.4-24.3% higher in producing bulls of spring birth season, and defect semen doses rate were lower by 1.1-3.0 percentage points compared to animals of other birth seasons. Indicators of reproductive function of producing bulls with mothers’ body weight was at the level of 561-600 kg, were higher by 6.9-45.5%, defect semen doses rate were lower by 1.2-1.5 p.p. compared to bulls with mothers’ lower body weight. Quantitative and qualitative indicators of bulls’ semen with productivity of mothers of fathers of 15-16 thousand kg of milk per year, exceeded the producers with lower productivity of mothers of fathers by 5.6-18.6%, and defect semen doses rate in these animals was 0.3-2.6 p.p. lower.

The paper presents research data with the purpose to study the traits of Holstein cattle breed of domestic selection. Based on many years of application of set of measures and modern highly effective methods of breeding work in dairy cattle breeding in the Republic of Belarus, Holstein breed of dairy cattle of domestic selection has been created. It was tested and an order was signed on the approval of this selection achievement (order of the Ministry of Agriculture and Foodstuff No.300 of 17.12.2020).

The value of complex index of bulls’ replacement heifers-daughters of red dairy breed has a fairly high level and is in the range of 104-111%, which is associated with the positive impact of producers on indicators of breeding value of their daughters. The average breeding value of bulls used in three generation intervals increased from 104 to 116%. A high and reliable repeatability of values of the complex assessment of replacement heifers of red Belarusian cattle at different ages (r = 0.98-0.99) in the conditions of the Republic of Belarus has been determined. It has been established that genotype of their fathers (η = 0.83) had the highest impact on the value of the index of comprehensive assessment of replacement heifers of red Belarusian cattle. 180 assessed replacement heifers of Belarusian red cattle are used for reproduction of the main herd of the UAE Noviy Dvor Agro of Svisloch district of Grodno region, 340 animals of the assessed replacement heifers of Simmental breed are used for reproduction of the main herd of the RAUE Experimental base Krinichnaya of Mozyr district of Gomel region.

To improve quality of the obtained embryomaterial and its acceptability in heifers, it is required to use preparations with general strengthening, immunostimulating and immunomodulatory properties affecting the ovaries of animals. One of such preparations is phosprenil. The aim of the research was to evaluate efficiency of phosprenil solution on the superovulation reaction and yield of high-quality embryos in lactating and culled donor cows. It has been determined that use of phosprenil solution together with hormonal agents at induction of multiple ovulation in donor cows makes it possible to obtain embryos of excellent and good quality 3.1 and 1.4 p.p. more than in the control, and embryos of satisfactory quality - 4.5 p.p. less, has a positive effect on yield of high-quality embryos, allows to obtain 3.90 embryos suitable for transplantation, which is 0.27 embryos or 3.8 p.p. more in comparison with the control, and to reduce the number of rejected cells by 0.24 p.p.

The paper presents research data with the purpose to establish biological functionality of semen of producing boars depending on synthetic media used for its dilution. It has been determined that composition of the improved GCCS environment will allow maintaining the quality indicators of diluted ejaculates at a high level during 3 days of storage, which is confirmed by the obtained values of motor activity and morphological integrity of the reproductive gametes. Comparative analysis of reproduction indicators showed that fertility rate of sows inseminated with semen with the extenders studied was at the level of 92.5-95%, while the difference in multiple fertility was more pronounced - up to 0.3 por.

In solving international and national agricultural programs, the priority is to preserve the genetic resources of livestock and develop ways to use them effectively, because in the world there is a clear tendency to reduce the breed composition of domesticated species of animals. Therefore, the purpose of our research was to analyze and highlight the current state of pedigree beef cattle breeding in Ukraine, as well as parameters of domestic breeds, which are the basis for breeding work and predicting their importance in breeding process. The State register of subjects of breeding business in animal husbandry for 2015 - 2019 was used for analysis. Methods of system generalization, graphic, analytical and comparative-statistical are used in research. Analysis of the state of development of beef cattle breeding in Ukraine was carried out. It has been determined that the largest amount of beef breeds cattle is concentrated in the north and west of the country, where natural and climatic conditions are favorable for creation of a developed field of beef cattle breeding. It has been established that the leaders in terms of number are Volyn and Chernihiv regions, and currently 52 breeding farms are registered in Ukraine, where 11 breeds of beef cattle are bred. The most numerous among the imported breeds is the Aberdeen-Angus breed. Among domestic breeds - Volynska and Polisska specialized beef breeds. It has been determined that in conditions of prolonged crisis in recent years pedigree beef cattle breeding in Ukraine has suffered a significant reduction in the amount, narrowing of the breed structure and changes in the form of ownership. In particular, in the period from 2019 to 2020, the sector of beef cattle in Ukraine suffered losses - the number of breeding herds generally decreased by 7%. Some breeds as Simmental and Southern meat breed decreased by 32-60% in number.

According to the results of the research, a reliable influence of inheritance of genealogical formations and the Holstein breed on the traits of dairy performance of stock animals of the Ukrainian black-and-white dairy breed has been determined. The best in terms of milk yield for the first and best lactation were the animals of plant line Valiant 1650414 (6927 and 8108 kg) and the genealogical line - P.F.A. Chifa (6580 and 7644 kg). The best in terms of milk yield for the first and highest lactation were crossbred animals with a high proportion of Holstein blood (87.6-93.8%), which prevailed over other groups of crossbred cows in terms of milk yield for the first lactation by 539-2264 kg with a high degree of reliability (P<0.001). Holstein bulls used in this herd led to complete absorption of blood of Ukrainian black-and-white dairy cows. At the same time, performance of purebred animals increased significantly even in comparison with crossbred cows with the highest Holstein blood count (87.6-93.8%) by 647 kg of milk for the first and by 468 kg for the best lactation (P <0.001).

The paper presents the results of studies of reproductive traits of sows of large white breed of different breeding values, the indicators of variability of quantitative traits and the level of their correlations have been determined. The research was carried out in agricultural formations of the Dnipropetrovsk region and in the animal husbandry laboratory of the State Institution "Institute of Grain Crops of the NAАS of Ukraine". The assessment of sows of large white breed for reproductive traits has been carried out taking into account the following indicators: multiple pregnancy rate, animals; heavy litter, kg; milkiness, kg; number of piglets at weaning, animals; litter weight at weaning at the age of 28 days, kg, safety, %. The breeding value of animals has been determined by the breeding index of reproductive traits of sow (BIRTS), scores. It has been found that in terms of multiple pregnancy (11.1±0.14 animals) and litter weight at weaning in at the age of 28 days (74.4±0.85 kg) sows of the control stock corresponded to the I class and the Elite class. The maximum indicators of reproductive traits are shown by animals of the M⁺ class according to the breeding index of reproductive traits (BIRTS). The criterion for selection of highly productive animals according to this index is 97.85-123.99 scores. The variability coefficient (Cv, %) of reproductive traits of sows of different distribution classes according to the BIRTS index varies from 3.92 to 11.69%. The number of reliable paired correlation coefficients between the indicators of reproductive traits of sows and the breeding index of reproductive qualities (BIRTS) made 83.33%. The above indicates the efficiency of the BIRTS index used in selection and breeding work.

The paper presents the materials of the work with the purpose to develop the optimal economic complex indices for maternal pig breeds. In the course of the research, the selection and genetic parameters of the Belarusian population of Landrace and Yorkshire pigs were determined. The economic significance of the selected traits has been calculated. Economic selection indices for assessing boars and sows have been developed, including parameters of their self-performance and reproductive traits. The accuracy of the indices was 0.617-0.783 for indices consisting of parameters of self-performance and combined, and 0.349 for indices of reproductive traits of sows.

The research to be predict the effect of selection at different intensity of selection according to complex breeding indices. The effect of selection of population of pigs of maternal breeds of the republic at different intensity of selection and matching of prospective fathers and mothers based on index selection. Correlation between the index score and the actual indicators of the selected traits has been established. Use of the best boars (5-10%) and sows (10-30%) selected according to the complex indices makes it possible to obtain replacement young boars with the average daily weight gain of 11-27 grams higher than their parents, and backfat thickness of 0.12-0.14 mm less, with multiple pregnancy rate of 0.03-0.09 animals higher than the average values of the initial experimental population, with insignificant or zero growth in parameters of litter weight at birth and the average weight of piglets by weaning. The predicted superiority of gilts over the average indicators of parents will be 11-16 grams in average daily weight gain, in backfat thickness - (-0.12) mm, in multiple pregnancy rate - 0.01-0.03 animals annually.

The paper presents materials of research on study of performance indicators of livestock breeding herds of plant type Pridneprovsky in Belarusian meat breed at basic agricultural enterprises. It has been determined that animals of breeding stocks of plant type Pridneprovsky of Belarusian meat breed at basic agricultural enterprises are characterized by high rates of growth and development. Values of indicators of multiple pregnancy rate, milk production ability, number of piglets and litter weight at weaning on average for all farms in sows made 11.5 animals, 54.6 kg, 10.0 animals and 81.7 kg. The indicators of the age of reaching body weight of 100 kg, the average daily weight gain from birth to 100 kg, the body length and backfat thickness in the plant type young stock made 181.8 days, 546 g, 123.5 cm and 18.1 mm, respectively.

Taking a three-year-old commercial carp to feeding with low-component compound since from July 20 and a two-year old since June 20 ensures fish productivity at the level of fish consuming standard compound feed K-111. No critical situations related to the ponds state had been observed during the rearing period. It has been determined that individual yield from fattening for a three-year-old made 85%, average weight 840 g, for a two-year-old - 85-86% and 410 - 440 g, respectively, which is slightly higher compared to standard. The fish productivity of the experimental ponds in the first variant for a three-year-olds, which received MCF since June 20, was no less than in the control one (14.9 c/ha). The weight gain of a two-year-old was at the control level (12.8 and 12.1 c/ha, respectively). In the second variant, where a two-year-old carp was taken to the MFC only since July 20, the fish productivity was higher than in the control. When studying feeding of a commercial three-year-old carp with low-component compound feeds, over 50% profitability can be obtained, two-year-old - 18-20 percent.

Pig breeding is developing successfully in the Republic of Belarus and in recent years has achieved high rates. The paper is devoted to the modern principles of rationing the amount of metabolizable energy and essential amino acids in compound feeds for all age and gender groups of pigs with high, genetically determined meat performance. Algorithms for calculating metabolizable energy both in individual feed ingredients and in compound feeds are proposed. The ratios of individual amino acids in mixed feeds are given among themselves and in relation to the energy level.

It has been determined that rearing two-year-old horses in winter using low-concentration diets with 20% of grain feed does not reduce the quality of the controlled horse population. A 20.8-35.9% reduction in feed costs is ensured compared to costs when using concentrate hay diets (30% of grain feeds). The perfect indicators of slaughter yield (58.2±0.88-58.4±0.27%), meat yield (3.73±0.04-3.81±0.04 units) of young animals have been achieved, breeding groups of horses of productive purpose have been formed.

The paper presents the results of studying the efficiency of including different doses of lactulose in diets for young cattle in composition of the starter compound feed KR-1. The research has been carried out at the State Enterprise “ZhodinoAgroPlemElita” of Smolevichi district, Minsk region. Inclusion in the diet of young cattle in compound feed KR-1 of lactulose in the amount of 0.8; 1.6 and 2.4% contributed to increase in the average daily weight gain by 6.0; 10.4 and 2.6%, increase in the amount of erythrocytes in blood by 6.2; 18.1; 15.6%, hemoglobin by 2.8; 3.6; 6.5%, hematocrit by 1.4; 13.7; 11.5% and a decrease in urea by 2.5; 5.1 and 7.6%, respectively, compared with the control group of animals.

Based on comprehensive assessment, winter triticale varieties Blago 16, IZS-1, Zhemchug, IZS-3, Svisloch, IZS-2, Kovcheg with high leafiness, green mass yield and nutritional value were identified to be used in the breeding process when creating new green cut varieties. It has been determined that varieties Blago 16, IZS-1, Zhemchug, IZS-3, Svisloch, IZS-2, Kovcheg can be used for setting up pastures and feeding pure green forage, starting from the booting phase and ending with the beginning of earing, as well as for harvesting hay and silage from the beginning of earing to the beginning of flowering phase.

It has been determined that different levels of oil flax cake in compound feeds relative to linen flax cake had a positive effect on productivity of young cattle at fattening, which was reflected in increase in the average daily weight gain on average for the experiment by 4.5-6.8%, growth or deposition of energy by 8.2-12.5%, energy conversion by 0.77-1.87 p.p., reducing energy costs for 1 MJ of gain by 6.9-11.0%. Feed costs for obtaining weight gain by 2.0-4.3%, crude protein by 4.2-5.5%, metabolizable energy by 2.4-7.2%. As a result, higher weight gain and relatively low feed costs contributed to decrease in price cost of rearing products by 8.7-10.8% during the period of the beginning of young cattle fattening.

The paper presents the results of studying the efficiency of granulated feed with and with no addition of Streptomyces levoris CNMN-Ac-01 biomass when feeding rabbits. For this purpose, two similar groups (experimental and control, 5 animals each) of rabbits of 60 days of age were formed. It has been determined that consumption of granulated feed by rabbits with addition of 0.1% biomass of S. levoris CNMN-Ac-01 promotes increase (in comparison with the control group) of body weight of animals by 6.16%; increase of meat ratio by 38.32%; reduction of granulated feed consumption for each kilogram of weight gain by 23.92%; obtaining additional gross profit of 1.24 $/animal or net profit of 0.72 $/animals.

As a result of studies, it was found that the use of peptide-amino acid chelated additive in an amount of 2% of the combined feed weight in the rations of bulls-manufacturers allows increasing ejaculate volume by 6.2% (P<0.01), sperm concentration by 9.5% (P<0.05), their amount in ejaculate - by 16.3% (P<0.001), contributes to obtaining more ejaculates and frozen

The paper presents the results of study of efficiency of domestic mineral tripoli used as a filler for enzyme feed additives containing xylanase, cellulase and β-glucanase. It has been determined that use of tripoli was a way to increase the efficiency of enzyme feed additives in compound feed concentrates for young cattle. Tripoli-containing enzyme feed additives used in the amount of 0.1% in KR-1 and KR-2 concentrate compound feeds contributes to increase in the average daily weight gain of young cattle by 6.0%, decrease in the price cost of gain by 3.4% and additional profit in the amount of 14.93 rubles for the experimental period, including 9.38 rubles due to replacing the “wheat flour” filler with tripoli. Inclusion of trefoil-containing feed additives in compound feed concentrates in the amount of 0.2% contributed to a significant increase in the average daily weight gain of young cattle by 6.4% and the level of feed consumption for the experimental period by 6.4%.

The paper presents the results of study of efficiency of chromium nanoparticles in diets for calves of over 75 days of age. Chromium nanoparticles in the amount of 0.050 and 0.075 mg per 1 kg of dry matter in diets as part of compound feed for young cattle of II and III experimental groups contributes to increase of the average daily weight gain by 3.4-5.8%, decrease of the cost of production by 2.2-4.7% and allows to obtain additional profit of 18.2-8.3 rubles per animal, respectively. Inclusion of nanochrome preparation in diets in the amount of 0.1 and 0.2 mg per 1 kg of dry matter of diet contributed to increase in the average daily weight gain of calves by 3.7% and 3.6%. Extra profit per 1 young animal in the experimental groups compared to the control made 8.8 and 14.7 rubles. The method of using chromium nanoparticles (liquid) in feeding young cattle of over 75 days of age is adding of preparation into concentrated feeds.

The oil-processing industry of the Republic of Belarus is a source of by-products obtained from the processing of oilseeds, which are highly valuable components of compound feed for farm animals. One of such products is soybean shell, which is a granular feed product obtained during production of soybean oil and high-protein soybean meal using extraction method. The purpose of our research was to study the efficiency of feeding highly productive cows and young cattle with different levels of soybean shell in composition of compound feed. It has been determined that introduction of soybean shell into compound feed for young cattle in the amount of 3% contributed to improvement in metabolism and increase in productivity by 9.0%, which contributed to additional profit of 6.55 rubles per animal. Introduction of soybean shell in the amount of 2 and 4% into compound feed for highly productive cows has a positive effect on milk production and economic efficiency of production/

The fundamental factor determining the level of dairy performance of animals is the energy contained in feed. Its main source and important component of plant feed are carbohydrates, which are divided into structural and non-structural. The aim of the research was to determine regularity of accumulation of neutral and acid-detergent fiber, energy value in the green mass of corn at various phenological stages of development. In the course of the research, it has been determined that accumulation of structural carbohydrates in the green mass of corn varied and depended on the phenological phase of plants. Certain peculiarities of accumulation in different parts of plant have been established. The results obtained indicate that content of structural carbohydrates also depends on content of dry matter both in the whole plant and in its various parts.

The paper presents the results of research with purpose to study the features of enzyme and microbial processes in rumen of young cattle using high-protein feed with “protected” protein for feeding. According to the data obtained, body weight gain increased by 7.9-8.3%, price cost of 1 kg of weight gain in groups fed with high-protein feed treated with acetic acid decreased by 5.97%, propionic - by 0.78%, which allowed to increase profit by 40.6% and 28.4%, respectively.

Production of new generation feed additives with functional properties is of great importance in balancing diets. These additives include sodium humate (huminate) obtained from peat and sapropel. The aim of the research was to study the efficiency of sodium humate used for feeding young cattle. The studies have been carried out in 4 groups of young black-and-white cattle with an average body weight of 79-81 kg, 12 animals each. The differences consisted in the fact that diet for steers of experimental groups included sodium humate in doses of 0.4 (II experimental), 0.5 ml (III experimental) and 0.6 ml (IV experimental) per 1 kg of body weight. It has been determined that sodium humate used in diet for steers as part of KR-2 compound feed had a positive effect on feed intake, physiological state, animals resistance, which ensured increase in the average daily weight gain by 3.2-9.4%, and decrease in price cost for its production by 2.9 -8.5 percent.

The paper presents the results of research with purpose to study the effect of pellet grain treated with organic acid on rumen digestion, physiological state and productivity of steers. Feeding young cattle at the age of 6-12 months with 10% of extruded lupine in the compound feed has a positive effect on physiological state of animals: the content of total protein in blood increased by 16.9%, glucose - by 6%, calcium - by 3.4%, phosphorus - by 6.4%, the level of urea decreased by 16.6%, contributes to increase in average daily weight gain by 7.04%, reduction of feed costs for obtaining weight gain by 5.47%, price cost of gain - by 4.0%.

One of the ways to increase nutritional value of feed is to treat it in a variety of ways to increase the efficiency of nutrient use or improve its quality. The aim of the research was to determine dependence of protein use and indicators of protein metabolism in young cattle on the degree of legumes grain grinding. In in vivo experiments with cannulated steers, it has been determined that protein of ground pellet grain decomposes by 75% within 6 hours, crushed grain - by 39% In the rumen fluid of steers receiving crushed grain, the content of volatile fatty acids decreased by 9.1%, which led to increase in the pH of rumen environment by 0.23. Content of total nitrogen in animals of the experimental group was 2.5% higher, protein - 5.1%, concentration of non-protein nitrogen decreased by 9.3%. Replacement of ground pellet grain with crushed grain instead of ground grain in the diets of young cattle aged 6-9 months improved the efficiency of the feed productive action. The average daily weight gain in experimental group increased by 6.1% compared with coevals fed with ground grain. As a result, feed costs for weight gain decreased by 4.2%. Feed protein utilization efficiency also increased by 4.1 percent.

The main task of commercial fish farming is to ensure the maximum yield of fish products in the shortest possible time. Therefore, food is needed with energy providing the maximum amount of plastic metabolism in fish. The aim of the research was to study the efficiency of using different compound feeds in carp feeding. As a result of research, new cheaper compound feeds have been developed, allowing to reduce the price cost of farmed fish by 20-25% in feeding marketable carp according to the developed scheme.

Healthy, well-developed young animals with high growth rates, capable of using feed efficiently is one of the main challenges facing the livestock industry. In this regard, the aim of the research was to establish the most efficient amount of protein in whole milk replacers for calves aged 10-30 days, which have a positive effect on physiological state and productivity of animals. As a result of research, it has been determined that the most efficient amount of protein was 22 and 25% in whole milk replacers for calves aged 10-30 days, contributing to increase in average daily weight gain by 11.1 and 12.2% while reducing feed costs by 10.6 and 18.2 percent.