The main breeding and genetic traits of reproductive (multiple pregnancy (animals), milkiness (litter weight in 21 days (kg), number of piglets at weaning (animals), litter weight at weaning (kg)) and fattening (age of reaching live weight of 100 kg (days), average daily weight gain (g), feed consumption per 1 kg of weight gain (feed units)) performance of pigs of maternal breeds. It has been determined that the following genes-markers of performance are promising for use in practical breeding for the maternal breeds of pigs: in reproductive traits -estrogen receptor gene (ESR); in fattening traits - gene of insulin-like growth factor (IGF-2). It was revealed that for pigs of maternal breeds of domestic selection (Belarusian large white, Belarusian black-motley breeds), the following trend is typical: with the growth of indicators of fattening performance, the reproductive traits are decrease. The species carrying the preferred genotypes BB and AB of the ESR gene in their genome surpass their coevals with the AA genotype in reproductive traits by 11.8-0.8%, but inferior in the fattening traits by 26.6-0.4%. And as for animals of the Belarusian plant type of Yorkshire breed - the animals are characterized by both high fattening and reproductive traits. This is due to the breeding work carried out with the plant type, which led to the predominance in the genome of animals of the preferred genotypes of ESR and IGF-2 genes.

An estimation of plant populations of pigs of Belarusian large white breed on the level of development and performance was carried out in the basic farms of the republic. It was revealed that animals of this breed have the following performance indicators: multiple pregnancy - 10.7 animals, milkiness - 51.9 kg, number of piglets at weaning - 9.8, age of reaching 100 kg of live weight - 180.2 days, average daily weight gain - 768 g, feed consumption per 1 kg of weight gain - 3.41 feed units, backfat thickness - 25.5 mm, hock weight - 11.2 kg. Analysis of estimation results of sows breed performance on reproductive traits showed that the highest indices of reproductive traits (IRT) had sows of related groups of Syabr 903 (121.53 points), Svat 3487 (121.89), Svitanok 3884 (122.30) and Skarb 5007 (123.27 points). Breeding herds of pigs of Belarusian large white breed of 1012 sows with the following performance: multiple pregnancy - 13.02 piglets, milkiness - 56.43 kg.

Correlation variability between the exterior articles of fresh cows of Ukrainian black-motley dairy breed in the system of linear classification of the type was studied. Between traits of one specific area, a positive correlation of different direction and significance was determined. Phenotypic correlations within the characteristics, less functionally related to each other, are characterized by high variability. Among descriptive characteristics that are included in the list of group articles, correlation variability is sufficient and reliable.

The paper dwells on results of studies according to analysis of polymorphism of leptin gene and its effect on milk performance of cows of Holstein population of domestic selection. It was determined that LEPA allele frequency varied from 0.207 to 0.375, and LEPB allele - from 0.625 to 0.793. On average, a reliable relationship was determined in farms between the indicators of milk yield, content and yield of milk protein, and allelic variants of leptin gene: in animals of LEPAA genotype milk yield for 305 days of lactation exceeded by 4.3 % (P <0.01) and 4.7 % (P<0.01) the similar indicator of groups of cows with LEPAB and LEPBV genotypes, respectively; cows with LEPB allele in homo- or heterozygous forms, by 0.10-0.14 pp were inferior to the animals with LEPAA genotype in protein content and by 8.4 (P <0.001) - 7.3 % (P<0.01) in milk protein yield.

As a result of joint experiments, new knowledge has been obtained on mechanisms of cryotolerance of cow oocytes, on the basis of which the method of obtaining embryos from intra-ovary vitified gametes has been modernized by using preventive VSV-diagnostics and introducing 0.001 % of highly disperse silica into the oocyte ripening medium. The preservation of thawed oocytes made 58.1-84.4 %, maturation - 44.4-60.0 % with the yield of splitting embryos of 7.1-18.2 %, including 5.5 % of blastocysts.

As a result of researches conducted, it has been determined that qualitative indices of producing boars’ semen and its fertilizing ability depend on application of sanitation preparation in diluent: cefepime, ampicillin and cefotaxime allowed to reduce the loss of moving activity of gametes within 72 hours of storage to 1.0 points, to minimize percentage of pathological forms of spermatozoa (8.6-10.4 %), to reduce the number of empties to 14.3 %, and to increase the yield of piglets by 8.9 % in comparison with the control.

Viability of using lines for selection of stren-cross is proved, since the offspring of this variant of selection differs by a significant advantage, both in terms of live weight in different age periods (by 22.3-45.9 kg) and also in terms of average daily weight gain (by 27-108 g). In this case, mating when selecting male and female of different plant lines related to each other through the ancestor (stren-cross) allows to improve the offspring with the exterior meeting the parameters of dairy cattle more closely.

The breeding potential of imported Yorkshire breed boars has been estimated in terms of parents performance (fathers and mothers), which is at the level of: the average daily weight gain - 1107 and 974 g, lean meat content in body - 61.6 and 61.4%, mother’s multiple pregnancy - 16.3 animals, the number of technological piglets on the 5 day - 13.7 animals, and for gilts - 1105 and 974 g, 61.7 and 61.5 %, 18 animals, and 15 animals, respectively. The average index of breeding value of boars and gilts made 118.0 and 110.8 points. The indices of fathers and mothers for boars made 120.7 and 100.4 points, respectively. Multiple pregnancy of sows averaged 11.1 piglets per farrowing, size and weight of litter at weaning made 10.7 animals and 96 kg.

Estimation of genetic potential is given in the article for Belarusian black-motley breed of pigs lines bred at gene pool breeding enterprises. Based on DNA testing by gene markers, it has been determined that two lines (Zarechniy 6069 and Tika 3037) are distinguished by a universal direction of performance. Boars of Kopyl 2107 and Slavniy 2663 lines are genetically predisposed to high meat-and-fattening performance.

The aim of the work was to estimate the breeding livestock of Aberdeen-Angus cattle in conditions of Pripyat Polesye. The research was carried out at CUPE «Mankovichy» of Stolin district. The research objects were cows and heifers of different breeds after crossing Aberdeen-Angus bulls with black and motley maternal livestock. 232 animals were valuated, including 111 cows. When characterizing exterior and constitutional traits of maternal livestock of Aberdeen-Angus breed, it was determined that cows belong to the elite-record class and correspond to the breed standard. Indices of stretchiness of cows made 117.7 %, pelvis-and-chest - 91.5 %, and massiveness - 142.8 %. According to set of traits, 63.3 % of animals are classified as elite class, to the elite class - 24.8 %, to class I - 11.9 %. According to the group of repair young animals, the distribution of animals is as follows: elite-record - 54.2 %, elite - 33.3 %, class I - 12.5 %.

Application of meloxicam solution reduces the number of posthumous detentions in animals after calving by more than 3 times (9.4 % in the experiment versus 30.8 % in the control), 5 times decreases incidence of females with postpartum endometritis (15.6 % in the experiment versus 76.9 % in the control), reduces duration of cows and heifers treatment with postpartum endometritis by 5.8 days, increases efficiency of estrus stimulation by 21.2 percentage points; increases frequency of pregnancy in repeatedly remaining barren cows by 25.3 percentage points.

The article studies the content variability of erythrocytes, leukocytes, hemoglobin, ESR index as well as numerous versions of micro-nucleus test and NOR (Nucleus Organizing Regions) Index. The studies were held for the inter-phase lymphocytes nuclei of the blood of heifers of the Ukrainian red-motley breed species that have various level of milk productivity. The studies displayed that the better the productivity do the heifers have the higher the erythrocyte and leukocyte values are. The direct and positive correlation between the milking of the cows, the level of erythrocytes and the level of hemoglobin is established. However, there was no connection found between the milk productivity level and the content of leukocytes in the blood. It is stated that the least level of erythrocytes that contain micro-nuclei is registered for the cows with a milking value of 3000-4000 kg. For the groups of cows that have the milking level of 6000 kg and above an abrupt increase of erythrocytes with micro-nuclei was detected, comparing to the groups of the lower milk productivity. The frequencies of the lymphocytes with micro-nuclei are slightly higher for the groups that have the productivity level of 3000-4000 kg of milk, comparing to the groups of productivity of 4000-6000 kg and is lower than the heifers with productivity of 6000 kg and above. By the coloration of the samples with silver nitrate it is stated that the least NOR number in inter-phase lymphocytes nuclei is applicable for the heifers with milking level of 3000-4000 kg, while the highest number is noticed for the cows of the productivity level of 5000-6000 kg. The average NOR Index among all researched groups of animals is 2.36.

As a result of studies on the effect of polymorphism of the estrogen receptor gene on the reproductive traits of sows of Belarusian large white breed, it was determined that the multiple pregnancy in animals with the BB genotype made 11.6 animals, that is higher than in sows with AA and AB genotypes by 0.9 piglets or by 7.8 % and by 0.5 piglets or 4.3 %, respectively (P≤0.01). The highest litter weight on 21st day had animals with genotype AB - 51.8 kg, that exceeds the one for sows with genotypes AA and BB by 2.0 kg or 3.9 % and 1.2 kg or 1.9 %, respectively (P≤ 0.001).

A comprehensive assessment of the breeding value of breeding livestock and producing bulls of the Aberdeen-Angus breed reared in the area of alluvial arable farming, was carried out. The breed composition, age, body weight, exterior and constitution traits of maternal livestock of cows and heifers, milk yield and reproductive capacity of cows, and genealogical structure of the herd were studied. Classes of animals in the herd were identified, where 2.8 % were assigned to elite record class, elite - 32.4 %, the first class - 49.4 %, the second class - 15.4 %, with 45.9 % of purebred animals belonging to the elite class, 45.0 % to the first class, of the first generation - 11.8% (elite), 54.9 % (I class), the second generation - 25.5 % (elite), 55.3 % (I class), the third generation - 28.5 % (elite), 45.7 % (I class), 25.7 % (II class) with a small number of the fourth generation animals (3 animals).

The article presents the results of studies on indices of reproductive traits of Landrace breed sows of French selection for the breeding period, the level of adaptation and phenotypic consolidation by traits with low heritability ratio. It has been determined that the highest indices by traits of «life expectancy, months», «duration of breeding, months», «number of farrows», «piglets born total, animals», «piglets born alive, animals», «fertility rate, animals» where peculiar of sows with index of «level of adaptation» varying in the range of 6.61 to 7.01 points. The phenotypic consolidation ratio according to the specified parameters in sows of Landrace breed (М^-) made K₁=0.160-0.706, К₂=0.196-0.756.

Based on components of general dispersion (variance), the selection and genetic parameters of experimental pig population were calculated. Heritability of studied traits showed the following values: average daily weight gain from birth to body weight of 100 kg - 0.71, backfat thickness 2 - 0.26, lean meat in body - 0.37, multiple pregnancy - 0.15, litter weight - 0. 34. It was determined that frequency of multiple pregnancy and litter weight traits according to the farrows made 0.10 and 0.19, respectively. The selection and genetic parameters obtained will be used for predicting the breeding value of pigs based on optimal mixed models (BLUP).

It was determined that aimed breeding in pig production in a number of generations according to reproductive traits and supporting selection (stabilizing selection) for improvement of fattening and meat traits allowed to improve them from generation to generation in a short period of time.

The maximum reproductive capacity was determined in three (only for multiple pregnancy) and four breed combinations obtained after crossing sows of large white breed with hybrid boars of BM×L, as well as two breed sows of LW×Y and L×LW. It was revealed that the best indicators of fattening performance were shown by three and four breed young hybrids of combinations LW×(BM×L), (BM×L)×L, (BM×L)×D, (LW×BM)×(L×D), (LW×Y)×(L×D), (L×LW)×(L×D), where the age of reaching body weight of 100 kg, the average daily weight gain and feed costs made 166-181 days, 760-803 g and 3.18-3.40 feed units, respectively. However, the absolute leaders in terms of age of reaching 100 kg of body weight and feed costs were four breed hybrids (LW×Y)×(L×D), which exceeded the best results of three breed young animals by 9.4 and 9.6 %. The highest meat content in carcasses was determined in young animals of combinations LW×(BM×L), (LW×BM)×P, (LW×BM)×(L×D), (LW×BM)× (D×P) and (L×LW)×(L×D), with the meat yield within the range of 67.5-70.5 %. Almost all three breed and with no exception all four breed hybrids had advantage for meat content in carcass over two breed and pure breed gilts of the compared groups by up to 11.0 %.

Differences in performance indicators of sows of Belarusian meat breed in basic husbandries in the context of genealogical lines were determined. The best indicators of multiple pregnancy was shown by: CJSC «Klevitsa» - sows of Belarusian meat breed when crossed with boars of Zefir line (11.4 animals), SHC «Zadneprovskiy» - sows in combination with boars of Zvuk 983 and Zubr 100426 lines (11.0 animals). At SE «ZhodinoAgroPlemElita» sows when crossed with boars of Zakat 53139 line by multiple pregnancy, milk yield, number of piglets and litter weight at weaning surpassed all the evaluated animals at the husbandry by 2.8 %, 1.0 %, 2.0 and 4.3 %.

Results of studies of phytocomposition «Vitastimul» effect in diets for young poultry on increasing their resistance to various infectious diseases are presented in the article. Hematological blood parameters were studied, as a result the effect of environmental factors on leukogram indices and indices of immune resistance was determined.

Inclusion of fodder concentrate, prepared of sugar beet processing byproducts (dry pulp, molasses and fodder defecate), in the amount of 15-25% in compound feed ensures increase in intake of dietary feed, increase in digestive processes in the rumen, which contributes to improvement of nutrients digestibility by 1.8-7.8% and nitrogen use for protein synthesis in the animal’s body by 3.6-7.8%.

Nitrogen-free extractive substances of cereals contain up to 72 % of grains energy reserves of these crops, including about 4 % of sugar and 68 % of starch. Carbohydrates of oilseeds (rape) account for about 8 % of energy reserves, peas - 64 %, soybeans - 13 %. After extracting the fat fraction from vegetable protein feeds, part of energy extracted from the carbohydrate portion increases up to 47.9 % in soybean meal, up to 46.3 % in rapeseed cake and up to 61.3 % in rapeseed meal. Thus, the metabolizable energy level in ingredients of cereals depends to a large extent on availability of nitrogen-free extractive substances, mainly sugar and starch. It is proposed to use the new calculation algorithm to determine the metabolizable energy level in feeds for pigs, which was not previously used in our republic, which includes quantitative indicators of raw nutrients level (protein, fat, fiber, starch and sugar), digestibility ratios of these substances and the constants of numerical values.

The article considers possibility of using legumes and cereals grass stand silage (multi stand silage) in diets for lactating cows of the first mowing. It was determined that inclusion of the studied preserved feed in diet of animals contributes to increase in the average daily natural milk yield by 8.9 % and decrease in feed costs by 7.7 %.

It is established that the use of biological preservative Bioplant-ultra for preparation of wet preserved corn at a dose of 4 grams per ton has a positive effect on preservation of feed and allows to prepare high quality feed with dry matter nutrition value of 11.88 MJ of metabolizable energy not inferior in nutritional characteristics to corn prepared with chemical preservative «Promir» (11.95 MJ).

As a result of researches it was determined that use of Bioplant-optima biological preservative based on strains of lactobacilli and fermented preparations allowed to obtain silage with nutritional value of 10.02 MJ per 1 kg of dry matter. Inclusion of ensilaged forages prepared with biological preservative in diets of lactating cows contributes to obtain the daily average milk yields of 19.3 kg while the cost of daily diet is reduced by 0.17 rubles, which makes it possible to obtain an economic effect per animal per day of 0.70 rubles.

The article comprises the results of two research-and-production experiments with meat of poultry and pigs grown on local forages including biologically active preparations. The purpose of the research was to study the effect of enzyme preparations «Cellolux-F» and protosubtilin G3x and probiotic feed additive «Sporotermin» on the intensity of growth, development and metabolic processes, and conversion of rations nutrients into production. The results of the research showed that to improve the physiological and biochemical status and intensity of metabolic processes in the body, and also improve the conversion of feed nutrients into products in composition of chickens and pigs mixed feed it is necessary to feed animals with the mixture of enzyme preparations «Cellolux-F» and protosubtilin G3x with probiotic feed additive «Sporotermin».

Feeding high-performance cows with premixes with Tripoli of «Stalnoye» deposit in Mogilev region as a filler in the amount of 70 and 100 % of the filler weight in compound feeds had a positive effect on morphological and biochemical composition of blood, as evidenced by a 6 % increase in hemoglobin, protein - 2.7 %, glucose - 1.8 % in the II group, and 7.7 % in hemoglobin in the III group, as well as mineral composition: the amount of calcium increased by 2.6 %, phosphorus - by 4.7 %, potassium - by 2.6 %, sodium - by 8.7 %, zinc - by 1.1 %, copper - by 16.6 %.

It was determined that watering high-performance cows with iodine concentrate during the milking period increases the intensity of protein metabolism, ensures glycolytic effect, stimulates neutralization of adverse changes due to intensity of metabolism during the milking period, contributing to saving metabolic equilibrium and having positive effect on intake and metabolism of nutrients in the animals’ body.

Digestibility of metabolizable energy of feed depends on various factors, including the content of non-starch polysaccharides that affect the digestibility of essential nutrients of feed, result in the decrease of the growth rate, efficiency of conversion of nutrients and the formation of sticky droppings, lower the quality of litter and the microclimate in the poultry house. Enzyme preparations mainly composed of Xylanase, Cellulase and β-glucanase, allow to avoid the negative impact of non-starch polysaccharides. Studies show that the best of modern enzyme preparations can be found among the complex additives, which activities are manifested as high as possible, they are suitable for the diets universal in components. The author studied the effectiveness of the diet with enzyme «Natuphos 5000». The composition of feed for broiler chickens, containing 50 % of naked oats during all periods of growing enzyme preparation «Natuphos 5000» was added at the rate of 100 g/t. Considering a favorable effect of the enzyme on the phytate complex in the experimental group the amount of added tribasic calcium phosphate and soybean meal was reduced, as compared with the control group. Due to increased splitting of essential nutrients and their release for building of body tissues, the live weight of broiler chickens was 4.5 % higher in the experimental group at the end of the experiment. Average daily weight gain of chickens in the experimental group during the whole experiment amounted 50.2 g, which is 6.1 % higher than in the control group. As a result, in the group where the enzyme preparation «Natuphos 5000» was used, the food conversion rate per 1 kg of live weight was reduced by 3.7 %, as compared with the control.

The article presents results of studies on the efficiency of feeding young cattle of 12-18 months of age with grinded and crushed pellets grain, as well as its effect on rumen digestion indices. It has been determined that in the rumen fluid of steers received crushed grain, there was a tendency of decrease in the amount of non-protein nitrogen by 3.3 % and ammonia by 6.8 %. At the same time, the number of infusoria increases by 4.3 %, and concentration of protein nitrogen - by 5.8 %. Replacement grinded pellet grain with crushed grain in the diets for steers contributes to an increase in the average daily weight gain by 4.1 %, and as a result the feed costs per kilogram of weight gain are reduced by 3.9 %.

The effect of chromium in the form of nanoparticles and sulphate on the performance of young pigs is considered in the article. The efficiency of different doses of chromium nanoparticles is presented with a different method of introducing them into diets of experimental animals. A positive effect of lower concentrations of chromium nanoparticles on the growth energy was determined.