In the conditions of the Republic of Belarus there was realized comparative evaluation of chemical composition and nutritive value of silages produced on the basis of millet (Panicum) and maize (Zea mays), their productive action and economic efficiency of ensilage fodders in diets of young stock of cattle. Data of chemical analysis showed the benefits of millet silage. The content of crude protein, crude fat, carotene, calcium and phosphorous was higher in millet silage. The analogous situation was in the analysis of biochemical indexes and energy value of dry matter. As a result of application of millet silage in diets of young stock of cattle made it possible to obtain 3,7 kg of body weight gain, while the expenses of forage per 1 kilogram of of weight gain lowered on 0,34 centner of fodder units, or 3,6%. Prime cost of 1 centner of fodder units in a diet in experimental group was on 57,3% lower than in a control one. Thus, use of millet silage in diets of heifers made it possible to lower the cost of fodders per 1 kilogram of weight gain on 63,2%, and prime cost of 1 kilogram of weight gain – on 19,8%.

In the conditions of the Republic of Belarus there was determined the influence of experimental feed mixtures on the basis of humid preserved grain (conserved rolled grain of triticale; barley (Hordeum vulgare); oat (Avena sativa)) and protein, mineral and vitamin supplement (contains rape (Brassica napus) extraction cake; wheat bran; premix PKR-2; chalk; forage phosphate) on digestibility and metabolism of nutritive elements by young stock of cattle. There were presented recipes of the developed experimental feed mixtures and studied their influence on consumption and digestibility of nutritive elements of diets, metabolism of nitrogenous substances, calcium, phosphorous, as well as on hematological indexes. The proposed mixed fodders contained metabolizable energy; dry matter; crude protein; digestible protein; crude fat; fibre; starch; sugars; calcium; phosphorous; magnesium; potassium; sulphur; iron; copper; zinc; cobalt; manganese. In course of the study there was analyzed the consumption of the main nutritive elements; coefficients of their digestibility; nitrogen balance; balance of calcium and phosphorous; morphological and biochemical blood indexes.

In the conditions of the Republic of Belarus there was determined the efficiency of application of different levels of vitamins and trace elements in feeding of servicing bulls. In course of the study there was analyzed the influence of different levels of supply of servicing bulls with vitamins A, D, E and trace elements (copper; zinc; manganese; iron; cobalt; selenium) on their reproductive ability. On the basis of the experiment there was calculated the economic efficiency of application of the developed vitamin and mineral additive. Research results showed that application of the developed protein and mineral additive in diets of servicing bulls in winter and summer periods made it possible to increase the ejaculate volume on 7,4% and 12,4% (P less than 0,05), sperm activity on 6,7 % (P less than 0,05) and 7,3% (P less than 0,01), concentration of spermium in ejaculate on 6,3% and 7,8% (P less than 0,05). Also, it promoted the lowering of percentage of defective sperm doses.