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%

Creation of a composition for disinfection of livestock houses which possessed an expressed sanitizing action and was safe for livestock animals after the repeated application was realized in the conditions of the Republic of Belarus. Formula of the presented the following components: potassium persulphate, amber and citric acids, sodium dodecyl sulfate. For strengthening of disinfecting effect there was also used detergent – sodium dodecyl sulfate (lauryl). Rational balance of components was selected and bactericidal properties of the preparation were estimated at the first stage of the study. At the second stage there was estimated theinfluence of the composition on livestock animals after the repeated aerosol spraying at their presence, as well as the biochemical, morphological and immunological blood indexes of experimental animals. Toxicity of the composition was realized by an example on white mice and rabbits. Research results showed that the composition for disinfection created on the basis of potassium persulphate and organic acids in the presented concentrations rendered the expressed bactericidal action, did not influence on metabolic indexes, had not skin and skin-resorptive action and could be used for air disinfection and surface areas of livestock houses in animal presence