The organizational aspects of reproduction in a swine heard were featured, the productivity indices of the crossbred sows obtained through the crisscrossing of the Belarusian Large White, Belarusian Black and White and Estonian Bacon pig breeds were given. The duration of the gestation period for the sows of different origin was shown. The results of the realized experiment showed that at all stages of reproduction there was required the full-value feeding and the maintenance of animals, observance of terms of revealing of sexual hunting and timely insemination of sow. For the systematic increase of swine productivity for selection of replacement pigs for reproduction besides the standard indicators it was necessary to consider the duration of gestation period. In course of study there was stated the well-defined consistent pattern of increasing of pig average weight which were born from sows with the lengthened gestation period. Piglets with the standard and extended term of prenatal growth showed higher indices of body weight at a birth and surpassed their herd mates with the shortened duration of prenatal development on 8,6-10,5% (Р less 0,001). Heavy litter of pigs affected the intensity of their subsequent development. At the weaning stage the weight of 1 pig with the shortened prenatal development was 6,25 kg, and the weight of pigs with the standard and extended periods - 6,62 kg (Р less 0,001) and 6,89 kg (Р less 0,001), respectively and exceeded on 5,9% and 10,2%. The 3-month age pigs with the shortened prenatal development lag behind herd mates with the standard and extended period of prenatal development in the indices of growing capacity on 1,2-1,4 kg (4,0-4,6%). The same tendency was noted after fattening period

The nonspecific resistance of cows at the interlactation period was studied for the forecasting of the postnatal period progress in the conditions of the Republic of Belarus. Influence of the complex preparations Erimetrinis and Richometrinum on restoration of cow reproductive function was investigated. It was established, that the developed new complex preparation Erimetrinis possessed the uterotonic, antiphlogistic, pathogenetic and stimulating action. Evaluation of the presented preparation was tested have under production conditions and confirmed its high efficiency. After application of Erimetrinis there was noted a fast restoration of both endometrias histostructure, indices of cellular protection, and cow clinical characteristic. Microflora which was discharge from cow uterus content, which were sick with postnatal purulo-catarrhal endometritis, was sensitive and high-sensitivity Erimetrinis and had a zone of growth inhibition from 19,6 up to 36,1 mm, while after Richometrinum application it was sensitive except for staphylococcus and diplococcus in which the growth inhibition zone was from 15,1 up to 15,4 mm. Study of indicators of bactericidal activity of cow blood serum in course of treatment with the Erimetrinis it was established, that starting from the fourth day of the treatment the analysed indicator increased up to 56%, and by the moment of the clinical recovery it was 82,4+/-2,16%. Indicators of lysozymic activity of blood serum at the moment of cow recovery were 13,4+/-1,35 mmol/l. Essential changes were marked in the phagocytic activity of leukocytes, phagocytic numbers and phagocytic index. Cows which were subjected to treatment with Richometrinum all mentioned above indicators were increasing starting from the tenth day of treatment beginning, and clinical recovery was stated on 7,4 days later than after Erimetrinis application

The influence of various light regimes on productive indices of broiler chickens cultivation of СОВВ cross taking into consideration the course of some exchange processes was studied in the conditions of the Republic of Belarus. There were formed 4 groups of one-day-old chickens with the approximately identical body weight. For the chickens of a control group there was used the standard for Belarusian poultry farms light regime, i.e. 23 hours of light and 1 hour of darkness (23L:1D), in three experimental groups there were used the following light regimes: first - (3L:1D) х 6, second - (2L:1D) х 8, third - (1L:1D) х 12. The predetermined conditions were set by means of filament lamps with 15 W capacity. Throughout the whole experiment there was realized the identical feeding level for all groups: during the first growing period (1-30 days) chickens were fed with mixed fodder PK 5B containing 22% of crude protein and 296,6 kcal of exchange energy, during second period (31-42 days) - PC 6B containing 20% of crude protein and 332,2 kcal. In the applied mixed fodders there was used enzyme Rovabio. Research results showed that metabolic processes occurring in chicken body in the majority opf cases depended on application of various light regimes. Interchange of light and darkness periods (3 hours of light and 1 hour of darkness) х 6 at light exposure in 15 lk rendered the positive effect on the activity of endocrine systems of chickens of СОВВ crosses. In mentioned above group of chickens the hormones directed their metabolic processes towards increasing the productive indices, namely: daily average gain of chickens of the first group was authentically higher than the same index in the second and the third groups on 13,6% and 17,9%, respectively

Influence of 33 imported heads Landrace breed boars of foreign selection on feeding performance and meat productivity of swine of the Belarusian Meaty breed was studied in the conditions of the Republic of Belarus for the enhancement of Belarusian breeds genealogical structure. There was stated the positive influence of Landrace Breed on feeding performance and meat productivity of mixed bred stores obtained after the introductive crossing with sows of Belarusian Meaty breed which was expressed in the predominancy of mixed bred hogs over the purebred ones at the stage of fattening performance test: at the age of reaching 100 kg body weight – on 0,7%; at average daily weight gain - on 1,5%; at feed consumption - on 1,2%. Mixed bred stores also had thinner back fat (on 0,9 mm) and bigger loin (on 0,4 square cm). There was stated the one-sided influence of boars of Landrace Breed on feeding performance and meat productivity indices of mixed breeds. It was established, that hybrids of four lines (Zaboj, Zalet, Zont and Bison) with regard to control groups showed the effect of heterosis at age of achievement of body weight of 100 kg, at a daily average weight gain and at forage consumption in the following rates: 1,5% (Р less than 0,05), 2,8% and 1,5% (Р less than 0,05) for Zaboj line; 2,3%, 4,9% and 2,1% (Р less than 0,01) for Zalet lines; 1,4%, 3% and 1,5% (Р less than 0,05) for Zont lines; 3% (Р less than 0,001), 6,7% and 2,7% for a line of Bison. In meat productivity indices there was stated the in-between character of inheritance which caused the decreasing of fat thickness and increasing of loin eye area at descendants of trial groups of lines: Zaboj, Zalet, Zenit, Zont on 0,88 mm (Р less than 0,05) and 0,6 square cm, 1,7 mm (Р less than 0,01) and 2,1 square cm (Р less than 0,001), 1,3 mm (Р less than 0,01) and 0,9 square cm, 1,4 mm

Research of the reproductive qualities of sows of different genotypes depending on duration of gestation period was realized in the conditions of an industrial pig complex of the Republic of Belarus. In course of research there were analysed 500 sows and 1991 farrowings and was stated that only 61,4% sows had gestation period in the range of physiological standards (at the average -11,5 days). In 17,8% of sows the mentioned above parameter was on 1,6 days shorter and in 1/5 of all sows under investigation it was 0,6 days longer. A higher productive performance was marked in double-breed sows of a genotype (White Large x Belarusian Meaty) with the average gestation period of 114,2 days. There were no essential deviations marked in the duration of the gestation period depending on the ordinal number of farrowing, though for the third farrowing the duration of the gestation period made 114,8 days and was 0,2-0,4 days longer as compared with the first and the second farrowings

In the research the genetic structure of populations of bulls Vitebsk of cattle breeding state farm and cows of Belarusian Black-and-White breed of Joint-Stock Company Olgovskij of Vitebsk region (Republic of Belarus) on a locus of a gene of kappa-casein was analyzed. As a result of genotyping a gene of kappa-casein by DNA-diagnostics method there were revealed three genotypes CSN3**AA, CSN3**AB, CSN3**BB. Frequency of occurrence of homozygous genotype CSN3**AA at cows has made 69,5%, at bulls of Vitebsk cattle breeding state farm - 78,3%; heterozygotic genotype CSN3**AB - 26,3% and 20,5%; homozygous genotype CSN3**BB - 4,2% and 1,2%, respectively. Frequency of CSN3**A allele in population of cows and bulls has made 0,83 and 0,88; CSN3**B - 0,17 and 0,11%, respectively. The presence of authentic influence of polymorphic variants of a gene of kappa-casein on level of milk yield and fat and protein content in cow milk was stated. The highest milk productivity in course of 305 days of lactation was observed at cows with homozygous genotype CSN3**BB (5984 kg), that was on 890 kg higher than in animals with genotype CSN3**AB (5094 kg), and on 1406 kg higher (Р less than 0,05), than at animals with CSN3**AA genotype (4578 kg). Cows with B kappa-casein allele in genome were characterized by higher fat content in milk (CSN3**AB - 3,61%, CSN3**BB - 3,72%) than animals with a CSN3**AA genotype - 3,60%. Cows with genotype CSN3**BB had higher level of protein in milk (3,28%) in comparison with the animals with CSN3**AA genotype (3,18%). In animals with CSN3**AB genotype the mentioned above index 3,19%. Research results showed that genetic variants of the gene of kappa-casein are important for selection practice as they could be used as breeding-genetic markers which could raise milk yields and protein content in milk

Results of determination of yielding capacity, chemical composition of initial weight and silage quality of forages prepared from the binary mixtures of Japanese millet (Panicum curs-galli var. frumentaceum), millet (Panicum) and saccharine sorghum (Sorghum saccharatum) realized in the conditions of the Republic of Belarus were presented. Research results showed that the binary mixture of saccharine sorghum with blue lupine (Lupinus angustifolius) in ratio of 70% + 30%, respectively made it possible to obtain the highest efficiency (62,4 t/ha of green material, 15,1 t/ha of dry matter, 13,1 t/ha of fodder units). Mixed sowing of millet, Japanese millet and saccharine sorghum with blue lupine surpassed in productivity the single-crop sowing on 15,5-32,6%. It was established, that the silage produced from the mixture of sorghum and Japanese millet with lupine had higher energy and protein nutritive value: 0,86 and 0,98 fodder unit, respectively; 9,77 and 9,92 mJ of exchange energy per 1 kg of dry matter, respectively; 103, 3 and 108,4 grams of digestible protein per 1 fodder unit. High nutritive value and the best palatability of trial silos promoted the increasing of milk yield on 4,4-5,4% in comparison with the control tests. Haylage which was produced from drought resistant crops had high energy nutritive value: per 1 kg of dry matter there was noted 9,40-9,48 mJ of available energy, 0,89-0,94 fodder units with fodder unit provision with 102-114 grams of digestible protein

Development of diarrheal diseases of newborn animals has a miltifactorial character and it is very difficult to optimize the structure of microbial population in alimentary tract and to carry out the correction of the microbe status only by means medical preparations. Therefore, for regulation of standard structure of intestine microflora in a complex of medical and preventive measures for diarrhea diseases of young poultry an important role is played by application of probiotics, prebiotics, and immunoamplifiers. In course of study there were used biologically active preparations produced on the basis of ecologically pure products of a natural origin: immunostimulant Alveozan, probiotics Bifidoflorin liquid and Dialakt, and prebiotics Biofon АIL and Biofon. Research was realized on one-day-old broiler chickens of Kobb-500 cross. The obtained data on the positive influence of the studied preparations on microbiocenosis of an alimentary tract of broilers chickens correlated with the indexes of natural resistance (autarcesis).The analyzed preparations made it possible to increase the local protection, stimulation of hematopoiesis (increasing of hematoglobulin, erythrocytes and leukocytes); to increase the blood content of whole protein, albumens and globulins, bactericidal activity of blood serum. Complex introduction of the analysed preparations stimulated the natural disease resistance factors, normalized the metabolic function of poultry, promoted the increasing of chicken livability and productivity

Nowadays in connection with an interdiction for antibiotics use in animal feeding it is very actual to work out and apply new forms of probiotic preparations which should be as ecologically safe and harmless both to people and animal products. Probiotics make it possible to improve the digestibility of nutritive substances of forages, normalize metabolism, enrich with biologically active substances that promotes the increasing of their productivity. In the Republic of Belarus the probiotics are produced in the obviously insufficient quantity that creates problems of young stock livability. Influence of application of Akozil and Sublicin probiotics in diets of suckling calves on biochemical parameters of blood serum was analysed. It was stated that use of the analysed probiotics made it possible to decrease the level of urea and total cholesterol, to increase of the total protein content in blood serum of the experimental calves. There was noted the increasing of glucose level in blood serum of calves fed with Akozil. There was marked the tendency of more optimal level of calcium and phosphorus in calves having Sublicin in their diets. The obtained results testified the normalization of metabolic processes taking place in calves which were fed by the mentioned above probiotics

The level of yielding and biological capacity of grass mixtures of feeding crops (common ryegrass (Lolium perenne); spring vetch (Vicia); Austrian winter pea (Pisum arvense); blue lupine (Lupinus angustifolius); common barley (Hordeum vulgare)) in the conditions of the Northern part of the Republic of Belarus and their quality evaluation were studied. The optimum temperature of seed germination at the seeding depth and the sufficient amount of moisture in soil provided high germination rate. Nitric fertilizer application and crop sowing in the conditions of various coenosis did not affect seed germination. The quantity of shoots predetermined the optimum plant stand density and made it possible to generate high green mass productivity. Formation of a high green mass yield in single-crops sowings of annual ryegrass was obtained against the background of minimum 180 kg of primary nutrients of nitric fertilizers per 1 ha, taking into consideration that the amount of crop tops increases in 3 times in comparison with crops without nitric fertilizers. Inclusion bean component into the grass mixture (even without nitrogen application) made it possible to generate the level of top biomass by three hay crops from 40,2 up to 55,4 t/ha. However, application of mineral nitrogen for cultivation of leguminous and cereal crop mixtures with overgrassing of annual ryegrass made it possible to increase the green mass productivity. Inclusion of a bean component into a grass mixture rendered influence on the amount of digestible protein. The highest protein yield was provided by high yielding crops with content of spring vetch on the background of mineral nitrogen (0,9 t/ha). In coenosis with pea and lupine mixtures provided protein content of 0,8 t/ha