Japanese millet (Echinochloa frumentacea) growing and yielding capacity was estimated in single and mixed sowings cultivated on sod-podzolic light loamy soils in the conditions of the Republic of Belarus; as well as comparative evaluation of silage quality and determination of digestibility of nutrients. Field experiment with forage crops was realized in threefold replication in accordance with the following scheme: Japanese millet (100%); Japanese millet (70%) + vetch (Vicia) (30%); Japanese millet (70%) + lupine (Luoinus) (30%); Japanese millet (70%) + pea (Pisum) (30%); Japanese millet (70%) + soybean (Glycine max) (30%). Research results showed that mixed sowings of Japanese millet with bean cultures made it possible to obtain higher yields than single sowings on 5,9-15,6%. Silage made of Japanese millet with bean culture contained higher amount of crude protein on 2,73-3,98% in comparison with silage which was produces only from Japanese millet. Silage produced from Japanese millet mixture with high protein crops had high energy and protein value: 0,90-0,92 fodder units; 9,47-9,59 mJ of metabolic energy per 1 kg of dry matter and 102-103 g of digestible protein per 1 fodder unit

While studying biochemical values that characterize rumen digestibility based on research agricultural experiment some results were obtained. These results prove that studied diets with increase of energy and raw protein concentration levels in dry matter influence positively at nitrous substances concentration activate micro flora motions and promote bio-synthetic processes in rumen fluid of experimental animals

Increase of diets nutrition energy in our experiment showed no significant effect on usage of nitrogen in feeds. Diets with different energy levels have no negative effect on hematological indices of animals

Improvement of the standards of energy and protein diets of young stock cattle of 1-6 month old and determination of its influence on animal productivity was realized in the conditions of the Republic of Belarus. The studied made it possible to determine that at the age of 1 month the calf diet should contain 1,02 kg of dry matter and 21,2 MJ of metabolic energy; at the age of 2 months - 1,26 kg and 23,5 MJ; at the age of 3 months - 2,2 kg and 25,6 MJ; at the age of 4 months - 2,9 kg and 31 MJ; at the age of 5 months - 3,28 kg and 34,2 MJ; at the age of 6 months - 3,76 kg and 37,6 MJ, respectively. Metabolic energy concentration per 1 kg of dry matter should not be lower than 20,7 MJ at the first month, 19 MJ - at the second month, after the third month it should lower up to 10 MJ. In course of 6 months the presented diet scheme made it possible get 832 g of average weight gain in the conditions of forage expenses of 3,52 forage units per 1 kg

Investigation of dynamics of indexes of carbohydrate and lipid exchange at piglets with various body weight at after weaning period, determination of possibility of their application as energy deficit markers, as well as studying the influence of vitamin and energy additive based on rapeseed oil on the indexes of carbohydrate lipid exchange in blood of piglets and their economic indexes were realized in the conditions of the Republic of Belarus. Research results showed that at the weaning period and after it there were changes in piglet organisms caused by adaptation to new housing conditions and that subsequently led to transformation of energy metabolism. After the weaning period there was stated increasing of level of lipid exchange in the energy supply of adaptation process, that was proved by the increased level of total lipids and triglycerides. Low indexes of carbohydrate and lipid exchange of the group piglets with low growth indicated to the insufficient level of energy supplying, needed for growth and adaptation. The studied vitamin and energy additives based on rapeseed oil corrected the level of carbohydrate and lipid exchange and could be used as a prophylactic agent against energy deficiency conditions of weaning piglets

Studying of the comparative productivity of various species and varieties of perennial grasses for the selection of the most productive species and increasing of production capacity of well-balanced feeds with low prime cost was realized in the conditions of sod-podzolic loamy soils of Vitebsk region of the Republic of Belarus. In course of study there were analyzed the following grasses: meadow clover (Trifolium pratense); creeping trefoil (Trifolium repens); great trefoil (Medicago sativa); timothy grass (Phleum pratense); meadow fescue grass (Festuca pratensis); chewing fescue (Festuca rubra); cock's-foot (Dactylis glomerata); common ryegrass (Lolium perenne); meadow foxtail (Alopecurus pratensis); awnless brome (Bromus inermis Leyss), and hybrid of fescue grass and perennial ryegrass. Studying of soil and climatic conditions in the analyzed area showed that leguminous grasses had higher yielding capacity than the cereal ones. After the 4-year observation the studied leguminous grasses provided higher yielding indexes in comparison with the cereal ones per 1 gram: dry matter – on 14,9%; available energy - on 29,7%; crude protein – on 44,7%. For the production of green mass in the conditions of Vitebsk region into the basis of planning of green and raw materials conveyor system there should be taken into consideration terms of beginning of hay cutting ripening of perennial leguminous and bluegrass grasses. Cereal grasses showed higher indexes of sugar content in 1,8 times in comparison with leguminous ones. For the provision of standard content of sugars and digestible protein in energy fodder unit it was reasonable to form grass mixtures on the basis leguminous and bluegrass grasses in ratio 60% and 40% respectively

Balancing of mixed feeds for replacement gilts considering the metabolically energy level and essential available amino acids amount increases growth speed of animals at 9,6% (P less than 0,05) compared to mixed feeds prepared in correspondence with detailed norms of feeding; it also decreases terms of animals pedigree usage from 277 to 223 days

Balanced complete feeding proved to be one of the major conditions of animal productivity increase and improvement of their reproductive qualities. Full value of feeding could be obtained at the expense of forage quality improvement and perfection of structure of the rations providing the increasing of metabolic energy use by breeding bull-calves. Analysis of the efficiency of metabolic energy use by the replacement bull calves under conditions of various sugar and protein ratio was realized in the Republic of Belarus. Research results showed that enrichment of replacement bull calves (with 325-405 kg of live weight) rations with easy digestible carbohydrates (sugar and starch) in ratio of 32% from a dry matter ration, including 15% of stable starch made it possible to increase the transformation of metabolic energy into energy of body weight gain on 21,73 - 23,96 MJ or on 10,3%, that as a result correspondingly increased the daily average weight gains on 7,9% and reduced the expenses for forage energy for 7,1% counting on an energy unit. According to the ejaculate volume indices the bull calves of the second experimental group surpassed analogues of a control group on 14,8%, and according to sperm concentration indices - on 12%. The average quantity of the frozen doses of sperm has made 65%