Results of studies of the influence of two biological products produced on the basis of sapropel (putrid mud) of the Ganarata lake (Mostovski district, the Republic of Belarus) on quality of legume-grass silage were presented. It was established, that analyzed preparations could be used as the preserving agents for preparation of herbal forages. The preserving action of the preparations was caused by the intensification of lactic bacteria development in silaging mass for the account of humic acids, as well as by the fungicidal action of phenolic and carboxylic fractions of the preparation. Silage preparation in combinations with putrid mud preparations made it possible to lower the losses of a crude protein on 11,3-15,6%, sugar - on 33,3%, carotin - on 20% and to obtain forage with concentration of exchange energy 9,20-9,38 mJ per 1 kg of dry matter. Silage application in combination with biological products rendered positive impact on milking efficiency of cows, the average daily milk yields in the experimental cow groups were on 1,3-1,4 kg or 6,8-7,3% higher. Application of higher quality feeds made it possible to lower the expenses of forages on 0,04 fodder units. Research results proved that the analysed preparations from sapropel could be used as an efficient conservants for silage preparations. They made it possible to raise forage quality at the minimum expenses

Determination of the efficiency of young fat stock feeding with wet rolled maize grain which was preserved by means of different preparations was realized in the conditions of the Republic of Belarus. The following preserving agents were applied: HV-2 (by- product of amino-formaldehyde resin); AIV 3 Plus (mixture of 62% formic acid and 24% ammonium formate; KEMIRA, Finland); carbamide (30 kg/t) with 40 g/t of complex mineral supplement. Feeding of young fat stock with rolled maize grains preserved by NV-2 promoted the increasing of nutrient digestibility on 1,5-5,0%, nitrogen use - on 2% in comparison with control. Application of rolled maize grain preserved with AIV-3Plus and carbamide with the complex mineral supplement made it possible to increase the digestibility of nutrients on 1,0-4,8% and nitrogen use - on 1,6-1,7%. Introduction of rolled maize grain preserved with NV-2 into rations of bull calves increased their productivity on 4,7% (P less than 0,05) with the simultaneous lowering of forage expenses on 1,9%. Application rolled maize grains preserved with AIV-3Plus made it possible to increase daily average weight gain on 3,8% and lower the forages expenses on 2,6%. Use preserved with NV-2 and AIV-3Plus rolled maize grains in rations of young fat stock lowered the production cost price on 11,9% and 10,8% that proved the efficiency of the studied fodder

Evaluation of maize (Zea mays) silage prepared in combination with biological preserving agent Laktotim and calculation of its economic efficiency were realized in the conditions of the Republic of Belarus. Application of Laktotim rendered positive influence on forage dry matter content, on nutritive substance safety, and made it possible to increase the organoleptic indicators of silage. Use of the maize silage prepared with the preservative in a cow ration has positively affected their dairy efficiency. Cow milk yields have raised on 4,5%. Application of the preparation for silage making of green maize mass proved to be economically worth. The realized toxicological estimation of biological preserving agent Laktotim did not reveal any signs of preparation toxicity. Introduction of the preparation into mice stomach in a single maximum dose (25000 mg/kg; 12500; 5000 mg/kg of body weight), as well as application of the preparation in mixture with water in ratio which in 100 and 200 times exceeded the standard ratio in plant green mass, did not cause destruction of experimental animals. According to classifications of All-Union State Standard 12.1.007-76, the preparation Laktotim belongs to the4 class of danger - low-hazardous substances (LD50 over 5000 mg/kg)

Traditional raw materials in Belarus for mixed fodders production are wheat, barley, oats, rye, peas, lupine, sunflower and rape cakes, bran. However, productive action of these forages is limited because of presence of antinutritious factors and the raised cellulose content. In the Republic of Belarus there was organized production of national enzyme fodder additive Fekord 2004. Peculiar feature of the presented enzyme complex was addition of into its structure of enzyme glucoamylase, promoting hydrolytic starch splitting, and accordingly, the increasing of absorbency of difficult carbohydrates of forages. It was especially important for stores at early stages. Thereupon it was expedient to study the efficiency of application specified multienzyme composition in diets of growing and fattened stores. It was established, that enrichment of mixed fodder with the analysed fodder fermental additive at the rate of 0,13 and 0,15 kg per ton of mixed fodder made it possible to increase the growth rate of pigs and lower charges for forages per unit of body weight gain. Higher economic return on the fodder enzymic additive an additional gain of body weight appeared at its introduction in quantity of 0,15 kg per ton of mixed fodder

Studying of influence of various levels of selenium on growth, protein structure of blood serum, natural resistance, and reproductive performance of pedigree bull-calves was realized in the conditions of the Republic of Belarus. It was established, that feeding with an optimum dose of selenium (0,4 mg per 1 kg of dry matter) in rations of replacement bull-calves during the raising period promoted the increasing of daily average weight gain on 6,8%, indexes of natural resistance - on 0,5-13,9%, and sperm production quality - on 4,5-27,3%. In the conditions of optimization of selenium level of in diets the protein structure of blood serum of replacement bull-calves exceeded the similar index at control animals by the crude protein index - on 8,3 (Р less than 0,05), by albumine and alpha globulin -on 2,2% and 1,6%, respectively. Application of selenium in dose of 0,4 mg per 1 kg of dry matter made it possible to increase the indexes of natural resistance on 0,5-13,9%. Increase of selenium dose up to 0,4 mg per 1 kg of dry matter in made it possible to increase the quantity and quality of sperm of bull-calves, that was proved by the increasing of ejaculate volume on 4,5%, concentration of male germ cells in ejaculate – on 15,7% (Р less than 0,05) and male germ cells activity - on 7,3% (Р less than 0,001)