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

Analysis of the efficiency of application of fermented milk supplementary feed DKM (Belarus) produced on the basis of bacteria strain Lactobacilus acidophilus 55/06 in calve diets was realized in the conditions of the Republic of Belarus. Influence of feeding with acidified with the trial milk additive on forage palatability, biochemical blood structure and calve productivity was studied; economic efficiency of DKM use for processing of whole milk and its use in rations of calves was defined. Experimental batches of DKM fermented milk supplementary feed were produced at Grodno Medical Preparations Plant (Belarus). It was issued in the sterile corked polyethylene 5, 10 and 20 liter bottles or canisters. The fermented milk supplementary feed DKM could be stored at the temperature from 0 deg С up to 15 deg С. Shelf-life – 3 months from the moment of production. The additive represents the homogeneous mass of viscous consistence of cream color of various shades with a sour-milk smell. The carried out economic calculations showed, that as a result of growing capacity increase it animals of a trial group and reception of an additional total live weight gain there was stated the 6,5% decrease of expenses for fodder unit production in the experimental group. However, due to a high cost of acidified milk the cost of fodder unit in trial group was on 6,8% higher. As a result, the cost price of 1 kg weight gain in trial group (despite high additional weight gains) was stated at the level of control group. Application of fermented milk supplementary feed DKM in calve diets made it possible to lower calf disease incidence and to increase calf productivity on 11,8% without increasing the cost price of production

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%