Various components and freezing modes are used for boar semen diluents, so it is 5 important to determine the effect of their composition and applied cryopreservation doses on semen quality. The paper contains the materials of research, which resulted in the development of a method for assessing the cryoresistance of semen and predicting its fertilizing ability after cryopreservation and defrosting, based on the relationship between the established acceptable limits of changes in the concentration of hydrogen ions, osmotic pressure, motility, integrity of sperm membranes after thawing and fertilizing ability. It has been found that the use of the experimental medium for pre-dilution and freezing of ejaculate allows obtaining values of hydrogen ion concentration of 6.7-6.9 and osmotic pressure of 310-315 mOsm, minimizing the reduction of ejaculate motility after defrosting to 4.5 points, preserving intact up to 51.1% of acrosome membranes and reducing the number of pathological forms of sperm cells to 17-20%. A complex of antibacterial drugs using recombinant human lactoferrin as part of the diluent contributes to high sperm sanitation results.

Evaluation of immunological compatibility in artificial insemination of pigs allows for optimal selection of parental pairs to improve the reproductive traits of sows. In the course of research, a biotechnology for the reproduction of pigs was developed based on new highly effective methods and means for improving the semen production quality and increasing the rate of fertilization. It has been found that positive immunological compatibility of parental pairs increases the sow fertilization rate by 4% (p<0.01) and the pig crop by 0.2 animals (p<0.05), while negative compatibility decreases the above indicators by 5% (р<0.01) and 0.3 animals, respectively.

The fecundity and prolificacy of sows determine the profitability of the industry as a whole. To increase the efficiency of insemination of sows, it is necessary to select the most appropriate ejaculates obtained from the best producers. The paper contains the research findings based on which an immunoresistant method of parental and maternal genetic material compatibility in the technology of artificial insemination of pigs has been developed. The influence of natural resistance factors on the state of the reproductive system of sows and their ability to realize physiological prolificacy has been established. The research has shown that the selection of parental pairs taking into account immunological compatibility and natural resistance factors of the organism increases the total number of piglets at birth and the number of live piglets, litter weight and a piglet average weight.

Pig farming efficiency increases under industrial conditions with breeding of certain, isolated breed lines. Involving a large number of geographically isolated populations in the study will make it possible to give the most complete characterization of the allele pool of breeds. The article contains the results of studies aimed at constructing dendrograms of maternal breed pig lines based on microsatellite analysis. The object of the study was the purebred populations of Belarusian Large White, Belarusian Black-and-White, and Belarusian factory type Yorkshire breeds of pigs. Identification of genetic relationships and differences between the lines using dendograms will enable targeted breeding work with boar lines for their preservation, improvement and effective use in the breed-forming process.

Presently, the number of pigs of the Belarusian Large White breed has noticeably decreased. To solve the issue of preservation and further development of this breed at the breeding enterprises of the republic, it is necessary to use more advanced methods of selection and genetic evaluation of pigs, that is according to the true genetic potential. The article presents the materials of scientific work, the purpose of which was to build genetic profiles of pigs of the Belarusian Large White breed at breeding enterprises of the Republic of Belarus. Studies have shown that animals of the Belarusian Large White breed have a fairly high frequency of preferred alleles for the RYR1 gene (the animals are stress-resistant) and the H-FABP gene (they have relatively high levels of intramuscular fat content), an average frequency for multiple pregnancy (ESR gene) and low in terms of fattening traits (IGF-2 gene). The construction of genetic profiles will make it possible to develop programs for selection of parental pairs taking into account the genotypes and alleles of marker genes of performance traits.

The use of transvaginal aspiration of oocytes (TAO) with their subsequent fertilization and thus obtaining embryos in vitro is largely dictated by the need of the livestock breeding industry for continuous genetic improvement of dairy and beef cattle. This area has become even more important after the introduction of genomic selection. In the technology of life-time in vitro production of bovine embryos, the qualitative and quantitative indicators of the initial population of viable oocytes determine the successful yield of blastocysts suitable for subsequent embryotransfer or cryopreservation. This paper describes the results of studies on the morphological features of oocyte-cumulus complexes obtained by transvaginal oocyte pick up (OPU). Analysis of the data obtained shows that the number of unsuitable oocytes during retrieval was approximately at the same level – 5.8% and 8.2% in the control and experimental groups, respectively. The proportion of oocytes with a layer of cumulus cells from one to three increased compared to the control by 27.1 and 17.7 p.p., respectively, and with a multilayer cumulus decreased by 47.2 p.p. The level of oocytes with a multilayer dense cumulus decreased by 10.2 p.p., and the level with a multilayer loose cumulus increased by 10.2 p.p.

Embryo transfer plays a major role in genetic improvement and accelerated creation of breeding herds: it allows increasing the young breeding cattle production by one cow, reducing the generation interval and significantly accelerating the process of qualitative improvement of the cattle population, which is especially important when introducing genomic selection into selection and breeding work. So, even nowadays, many breeders obtain their young stock exclusively through the embryo transfer applying superovulation or in vitro technology. In this regard, the effectiveness of the two-year work on embryo transfer at JSC “Gastellovskoe” of the Minsk region was studied. According to the results of the two-year work, 1,380 embryos were produced, of which 79.5% were suitable for transplantation. The yield of viable embryos in the spring period was generally higher than in winter, summer and autumn by 4.6 p.p., 3.8 and 9.8 p.p., respectively. With an average yield of viable embryos per donor of 4.2-4.3, depending on the bull, this index ranged from 1.0 to 6.8. The oocyte fertilization rate was approximately at the same level and amounted to 80.9-81.6%.

Monitoring of thoroughbred horse breeding in Belarus shows that, despite the reduction in the total number of commercial horse breeding stock, the available breeding resources are preserved. Horses of the Belarusian harness breed are in demand not only in breeding work, but also in the social life – for recreation, tourism, equestrian sports, etc. This paper contains the materials of research, the purpose of which was to assess the quality of the Belarusian harness horse breed and the prospects of its further improvement under the new conditions of use. It has been established that the horses kept at thoroughbred breeding farms exceed the breed standards in all quality indicators. Based on the data obtained, model indicators of stallions and mares have been developed for the planned new conditions of their use, including in mass equestrian sports and leisure horse breeding.

Methods of molecular genetic analysis are widely used to assess the genetic structure and study the dynamics of population genetic processes in populations of animals, which will allow to preserve and improve the unique traits of the Belarusian Blackand-White breed of pigs. This paper contains materials of microsatellite analysis of the Belarusian Black-and-White breed at KSUP Plemzavod Lenino, SGC Vikhra and OJSC SGC Zarechye, carried out to determine heterozygosity or genetic diversity of the population, the degree of inbreeding of animals in the lines. The Belarusian Black and-White pigs have five loci (SO005, SO386, SO355, SO155 and SW857) out of nine with confirmed significant deviation from the state of genetic equilibrium. The greatest number of “private” alleles was identified among the animals bred in OJSC SGC Zarechye. Boars with determined “private” alleles at microsatellite loci reliably confirm their linear affiliation and are considered to be successors of the same-name lines. This gives reason to consider these alleles as marker alleles for these lines and use them in breed selection and preservation.

One of the factors for effective development of dairy cattle breeding is the increase in the number of highly productive lines, the animals of which are characterized by a high level of milk productivity and suitability for machine milking. In this connection, the purpose of the research was to analyze the milk productivity and breeding value of first-calf heifers of different origin. It has been established that the first-calf heifers in the herd are descendants of 15 stud bulls of foreign selection (USA and Canada). The first-calf heifers of the Reflection Sovereign 198998 line exceeded the herd averages by 0.4%, 1.1% and 0.3% in milk yield, milk fat and milk protein, respectively. The average live weight of the first-calf heifers was 543 kg, milkability index was 1896 kg. The highest complex indices for milk productivity were observed in daughters of Motocross 750585 bulls of the Vis Aidiala 933122 line (113.1 %), Colossus 750459 (112.7 %) and Dunphy 750523 (111.7 %) of the Reflection Sovereign 198998 line.

One of the common causes of decreased fertility is abnormal sperm morphology. Therefore, a rigorous selection of spermatozoa for fertilization according to morphological parameters is required to reduce the frequency of sex chromosome aneuploidies. The paper contains the materials of research, as a result of which a classification for assessing the intravital viability of bovine spermatozoa suitable for ICSI was developed, and recommended parameters were highlighted, including the use of sperm capacitated in vitro, rated at 0 points for the presence of foreign microflora, i.e. free from flora or with single cells in several fields of view, a degree of motility and translational movement of level A (actively motile with translational movement), without proximal and distal drops, without defects in the head, body and tail of the sperm, having a teratozoospermia index of 1.0-1.3.

This paper presents the data of the work, the purpose of which was to study the conditions for preparation of bovine spermatozoa for intracytoplasmic injection. As a result of the research, the conditions for successful preparation of frozen-thawed semen of Holsteinized bulls for intracytoplasmic injection were determined. It has been established that the use of a culture medium for capacitation based on Tyrode’s solution containing cresacin at a concentration of 3 mg/ml or recombinant human lactoferrin at a concentration of 1 mg/ml ensures the absence of proximal drops in 100% of spermatozoa after capacitation, distal drops in 94.6-95.2% of spermatozoa, curved tails in 99.6-100% of spermatozoa, as well as obtaining 85.5-86.5% of morphologically normal spermatozoa without defects in the head, body and tail, and overall gamete motility indices at the level of 68-77%, while maintaining the optimal parameters of speed, trajectory and amplitude.

At present, the introduction of new developments based on DNA testing into the practice of riding horse breeding is urgent. Their use contributes not only to increasing reproduction rates, but also to solving the most difficult problem of replication and preservation of unique genotypes of horses that meet the increased requirements for their multi-faceted use in various equestrian disciplines. This paper is devoted to the study of the relationship between polymorphism of microsatellite DNA loci and performance of riding horses. It has been established that the frequency of alleles ASB17G, ASB23J, CA425I, HMS2M, HMS2H, HMS3J and HMS3Q in the corresponding microsatellite loci is significantly higher in riding horses with athletic performance score over 7.5. Also, a number of alleles that reduce the athletic performance of horses have been identified. The data obtained can be used as markers for selecting promising horses for equestrian sports.

In pig breeding, in contrast to dairy cattle breeding, the system of commercial production consists of different levels of breeding work: nucleus, multipliers and industrial producers. To optimize the calculation of economic value, it is necessary to use a methodology that allows us to divide the contribution of a particular level of breeding enterprise, breed and gender of pigs in the profit received from the production of a marketable animal. In this connection, the analysis of changes in the accuracy of the selection index depending on the initial selection and genetic parameters and aggregate genotype was carried out. A composite index, including two traits, was used for stud boars: average daily gain (ADG) and fat thickness (FT). A non-linear dependence of reliability and heritability coefficients was found, with reliability increasing from 5% to 13% as the heritability coefficients increased by 10%, indicating a more reliable estimate for traits with high heritability. It was found that the economic value of the traits had an impact only on the dimensionality of the developed index.

The study of genetic polymorphism of various breeds of farm animals is an important area of modern population genetics. Microsatellites are easy-to-analyze genetic markers in the genome of animals; however, their use in the practice of pig breeding requires a wide range of studies aimed at assessing their applied significance. In this connection, we studied the genealogical structure of Landrace pigs bred at the agricultural branch “SGC “Zadneprovsky” of JSC “Orsha bread products company” based on DNA-MS analysis. When analyzing the intrabreed genealogical structure of the studied animals, it was found that pigs of the Zamka and Zaliv lines were distinguished by the greatest genetic similarity with animals of other lines. The cluster structure of Landrace pigs, based on the results of microsatellite DNA analysis, is completely consistent with the data on the origin of pigs.

In obtaining the planned volumes of high-quality livestock products, an important role is assigned to the compound feed industry, since the use of compound feed balanced in nutrients, minerals and biologically active substances allows you to make the most of the genetic potential of animals, increase productivity, and reduce feed consumption. Feed protein deficiency remains one of the crucial problems in feeding cattle, so to get more and better quality products, it is necessary not only to provide animals with high-quality feed, but also to develop technological methods that regulate fermentation processes in the rumen. One of these methods is the treatment of feed in a variety of ways to increase the efficiency of nutrient use and improve its quality. The paper contains the materials of the study of the dependence of protein use and protein metabolism indices of young cattle on the applied chemical methods of highprotein concentrates processing. It has been found that the use of acid-treated grain in diets for young cattle reduces the content of ammonia in rumen fluid by 12-17.5%, ciliates – by 4.7-9, and volatile fatty acids – by 6.8%, thereby increasing the growth energy by 5.0-7.2% and reducing the feed costs by 3.3-5.0%.

Currently, farm animals are not provided with protein according to science-based standards. There is also a lack of macroand micronutrients in diets, which play an important role in all metabolic processes of the body. Cattle have a unique ability to synthesize their body protein from non-protein nitrogen-containing synthetic nitrogenous substances. In this regard, the aim of the research was to study the effect of these substances on the compound feed protein degradability. It was found that the inclusion of diammonium phosphate and urea phosphate in the compound feed had no significant effect on its composition. The level of crude protein in the experimental compound feed for young cattle was 136.8-144.3 grams per 1 kilogram. Feeding young cattle with a synthetic nitrogenous substance of non-protein nature in the form of diammonium phosphate and urea phosphate in the amount of 3-6 % by weight of the compound feed increased the compound feed protein degradability by 3-8 p.p. and was 83-88 % after 24 hours.

Intensification of dairy and beef cattle breeding is associated with adequate balanced feeding and rational use of feed, based on improving its productive effect and increasing the transformation of nutrients contained in feed into animal products. This can be achieved by using herbal supplements containing tree biomass. The aim of the research was to study the effectiveness of the use of conifer energy supplements in feeding cows. In the course of the work, a positive effect on the redox processes in the body of animals was established. Feeding conifer energy supplement to cows during lactation provided an increase in the average daily milk yield of basic fat level by 4.5 and 1.7 kg.

Properly organized conditions of calf housing and feeding contribute to high efficiency of cattle breeding. Many factors influence the body formation of young animals, one of which is the use of properly selected diets that affect the level of subsequent productivity of adult animals. This paper contains the materials of research, the purpose of which was to determine the effectiveness of calf growth in the post-weaning period when feeding whole corn grain in the pre-weaning period. It has been established that the inclusion of whole corn grain in the amount of 30 and 40% by weight of compound feed in the diet of preweaned calves has a positive effect on feed intake, improves digestibility of nutrients and increases the amount of total protein in blood serum, reduces the concentration of urea, activates the intensity of physiological and biochemical processes in the rumen of postweaned animals, increases the average daily gain by 9.1 and 4.3 % with a decrease in its cost by 7.4 and 3.9 %.

Recently, turkey farming has received the most attention in order to provide the population with highly nutritious dietary meat. The health benefits of turkey are also due to the fact that one serving of turkey meat contains a full daily allowance of omega-3-unsaturated fatty acids that improve cardiac function and increase brain activity. The purpose of our work was to study the effect of the mineral feed additive “Cu-Aktiv” on the productivity of the Big-6 cross turkeys. Scientific and economic experiment was carried out at the production site “Haisy” of JSC “Poultry farm “Gorodok” of Vitebsk region. It was found that the use of patented mineral feed additive “Cu-Aktiv” at the rate of 0.001% of compound feed provided an increase in the average live weight of turkey poults by 20.3%, average daily gain – by 20.5%, livestock livability – at least 93.5%, while reducing the feed consumption per product unit by 5.4%. Based on the positive results obtained, we recommend using the domestic mineral feed additive “Cu-Aktiv” in the diets of the Big-6 cross turkeys.

Cattle feeding with the consideration of its biological properties promotes normal growth and development, formation of high productivity and prolongation of the terms of economic use of animals. An important role in this is played by the provision of animals with nutrients, minerals and biologically active substances, which in various ratios affect the processes of nutrient transformation and productivity of farm animals. When balancing the diet in terms of protein nutrition, it is necessary to select its components in such a way that protein and energy are evenly used by animals during the day. In this regard, the aim of the work was to determine the patterns of rumen metabolism in young cattle aged 12-18 months when fed diets with different ratios of degradable and non-degradable protein. Studies have revealed that the optimal content of degradable protein in the diets of young bulls aged 12-18 months is 65-70%. Economically sound and feasible are diets with a protein degradability of 70%, since in this case feed costs are reduced by 5.0%.

Winter triticale is characterized by high yield and nutritional value of green mass, and the climatic conditions of Belarus are quite favorable for the cultivation of this crop to obtain high-quality feed in early terms. The aim of the research was to study the yield and nutritional value of winter triticale compared to rye with two cuttings during the booting stage. As a result of the research, high-yielding varieties of winter triticale Dynamo, Slavko, Kovcheg and IZS-8 were identified, which exceeded winter rye in terms of green mass yield for two cuttings during the booting stage by 14.7- 43.8 %. The studied varieties of winter triticale were superior to winter rye in terms of the content of crude and digestible protein, crude fat, and also had a lower fiber content, so they can be used in green conveyor system.

It is known that the efficiency of fish breeding directly depends on the use of high-quality, well-balanced and inexpensive feed. Presently, chlorella suspension is widely used to improve compound feed formulations. This is due to the presence of pigments, antioxidants, provitamins, vitamins and growth substances that can stimulate the immune system and increase feed intake and utilization. Other plant components which are perspective in the production of mixed fodders for fish are rapeseed and safflower dye. These oil crops were introduced into compound feed in the form of cake to provide the necessary amount of fats and protein. The aim of the research was to study the effect of rapeseed and safflower cake and chlorella suspension as part of compound feed for fish on the biochemical blood parameters of juvenile sharptooth catfish. The research found that the introduction of the studied components into compound feed had a positive effect on the biochemical parameters and physiological state of fish.

One of the most important criteria for the quality of the feed is the stability of the indicators guaranteed by its manufacturer. Arrangement of optimal storage conditions, compliance with norms and rules for the use of various feed additives provide a productive effect. The aim of our work was to study the stability of fermentation activities of the Fekord-MP dry enzymatic feed additive in different modifications (group 1 and group 2). The tests for compliance of the enzymatic feed additive with the requirements of technical specifications TU BY 200058575.042-2018 were conducted in vitro at the beginning and after the storage period according to the generally accepted methods. The research found that during the storage period of 1 year, the Fekord-MP dry enzymatic feed additive in different concentrations (group 1 and group 2) met the requirements of technical specifications in terms of physical and chemical properties. Under observance of storage regulations, the stability of the quality indicators of fermentation activities declared by the manufacturer is preserved.

Complete, balanced on the content of energy, organic, mineral and biologically active substances feeding dry cows and heifers promotes their high productivity and longevity of their use. Minerals and vitamins help to avoid metabolic disorders in cows, stimulate the immune system of animals, and also, entering the body of animals, pass into milk, thereby influencing its composition and quality. However, there is of- ten a lack of them even in good-quality feed, which can be compensated by the use of feed additives. This paper contains the results of scientific work aimed to establish the dynamics of milk productivity of cows when using “Megachance-I” and “Megachance-II” feed additives in the diets of the 1st and 2nd phases of dry period. The research has shown that their use in feeding cows during the dry period allows to increase productivity in the following lactation by 5,2-5,5 % and to increase a mass fraction of fat by 0,24-0,25 p.p., a mass fraction of protein by 0,08-0,09 p.p., a mass fraction of lactose by 0,30-0,36 p.p. and to lower a content of somatic cells in milk by 17,5-29,2 %.

Good nutrition improves the productivity of stud bulls and helps to increase the duration of their intensive use. However, there is a deficiency of micronutrients in the diets, which drives the need for the use of mineral supplements in animal diets. Chromium nanoparticles have low toxicity and are capable of forming biologically active complexes in the body. The paper presents the results of studies on determining the efficiency of using the Nanoplant Chromium (K) feed additive in the diet of stud bulls. It has been found that the inclusion of this feed additive in the amount of 0.2 mg per 1 kg of dry matter in the diet for stud bulls promotes increase of chromium content in the daily diet by 30.0%, improvement of hematological parameters and increase of quantity and quality of semen by 2.5-13.0%. 

During manufacturing of fat-and-oil products, numerous fatty wastes and byproducts are formed at various stages, which have feeding value and are not used as feedstuffs on an industrial scale. In this regard, farm animal feeding is the most promising area of use of the solid waste fraction or olive cake. This paper contains the results of studying the effect of “Oemix-P” and “Oliplus” feed additives in cows’ diets on the morpho-biochemical composition of animal blood. During the period of scientific and economic experiment, their positive effect on morphological and biochemical blood parameters of cows of the first lactation period (0-100 days after calving) was established. The use of compound feed concentrates for dairy cows, containing 0.7% of the “Oemix-P” and 0.8% of the “Oliplus”, helps to increase the rate of metabolism in the body of animals.

Presently, for the purpose of import substitution, there is a need for cheap sources of raw materials for the production of feed additives that enrich animal diets with basic nutrients. Secondary products of oil extraction industry can be used as such sources. The paper contains the results of research aimed at studying the effect of fatty bleaching clay included in the composition of compound feed on the productivity of young cattle. For this purpose, a scientific and economic experiment on three groups of calves selected according to the principle of paired peers with regard to age and body weight was carried out in the RSUE “ZhodinoAgroPlemElita” of Smolevichi district, Minsk region. The research has shown that putting 0.5 and 1.0 % of fatty bleaching clay into the compound feed for young cattle provides an increase in the productivity by 10.3 and 9.0 %, while reducing the feed costs by 5.23 and 2.7%.

Proper feeding of calves allows you to make the most of their genetic potential for maximum productivity. Inthe pre-weaning period, functional changes in the calf digestive system take place. They grow quickly,so they are fed according to schemes, which are drawn up in accordance with the norms and taking into account the economic conditions. The paper describes the results of research, the purpose of which was to develop a calf rearing system with optimal duration of pre-weaning period, ensuring normal course of digestion processes, high resistance and productivity of animals in the post-weaning period. The research showed that in calves fed whole and skim milk replacers during the pre-weaning period, microbiological processes in the rumen were more active in the post-weaning period. It was also found that feeding WMR and SMR to young calves, whose pre-weaning period lasted for 90 days, contributed to an increase in average daily gain in the post-weaning period by 5.4% with a decrease in the cost of gain by 4.4%, which allowed to obtain an additional profit of 6.64 rubles per head for the period of research.