Development of new compositions of premixes for cows with milk yield of 4-5 thousands kg per lactation depending on lactation stage and pregnancy was realized in the conditions of the Republic of Belarus. Efficiency of application of premixes in comparison with the standard ones was estimated. Experiment was realized by an example of 3 groups of cows of white-and-black breed; experimental period included beginning milking period (90 days) and the main lactation period (142 days). Cows of the first control group were given premix P60-6M with combined feed. Animals of the second group were fed with premixes created on the basis of carotene and microelements content. Cows of the third group were given premixes in accordance with recommended standards. The refined standards of cow vitamin and trace elements consumption were presented. Formulas of premixes for high-producing cows were presented. The research results showed that the developed formulas corresponded to the physiological needs and their application influenced on metabolism and milk producing ability. Application of experimental premixes made it possible to increase the digestibility of nutritive substancesoin 2,3-7,5%. Application of vitamins and trace elements in heightened doses (on 10-30%) caused the increasing of their uptake and increasing of cuprum, zinc, manganese and cobalt content in blood on 11,6-40,8%

A technology of application autolysis of fodder yeasts (AFY) for the production of products with higher protein content, digestible aminoacids and other nutritive and biologically active substances in comparison with the standard fodder yeasts (provit) was tested in the conditions of the Republic of Belarus by an example of three groups of swine. Animals of the first (control) group were fed with combined feed SK-26 with addition of 2% of provit. Animals of the second group were fed with combined feed SR-26with addition of 2% of AFY, the third group - with addition 4% of AFY. Provit and AFY were included into combined feed instead of excluded protein components in equivalent number. Research results showed that autolysis of fodder yeasts did not render negative influence on productivity of fattening stores. Average daily weight gain of stores was 637-674 g. Calculation of economic efficiency of combined feeding application of 2 and 4% of AFY showed that application of 2% AFY was more economically profitable