In the conditions of the Republic of Belarus there were studied biochemical indexes of calf blood serum against the background of application of probiotic preparations Bilavet C. Results of research showed that administration of probiotic preparations from the first day till the six day and from the fourteenth day till the nineteenth day of calf life with the preventive purpose rendered the simulative influence on indexes of natural resistance, which were accompanied with the increasing of total protein quantity in blood on 2,9-5,9%, as well as the increasing of protein fractions, in particular, globulin-rich fraction on 4,2-6,4%. Administration of probiotic preparation Bilavet С to calves rendered the positive influence on blood biochemical indexes, promoted the uptaking and better accumulation of mineral substances: content of crude calcium, inorganic phosphorus, magnesium, iron increased on 15,3%, 10,5%, 13,2% and 3,6%, respectively.

In the conditions of the Republic of Belarus there was analyzed the influence of inclusion into broiler chickens diets of probiotoc preparation Bifidoflorin zhidkij (liquid) and prediotic veterinary drug Biofon AIL on the natural resistance, hematopoiesis, growth, metabolic function, development and viability of broiler chickens. In course of the study there was analyzed the dynamics of total haemoglobin, total protein of blood serum, albumins and globulins of broiler chickens which were fed with veterinary drugs probiotoc Bifidoflorin zhidkij and prediotic Biofon AIL. Indexes of chicken viability and life weight gain were marked. Research results showed that application of the presented veterinary preparations rendered the growth promoting action, lowering of disease incidence, increasing of chicken viability, increasing of live weight gain and stimulation of metabolic processes in the most intense period of poultry growing. All these factors were expressed in highest degree after the combined application of the probiotic and prebiotic veterinary drugs.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of a probiotic lactic casein feed additive DKM which was developed in the Institute of Microbiology of the National Academy of Sciences of Belarus. The analyzed additive contained specially selected lactic-acid bacteria with a high bioartificial potential of metabolites. In course of the experiment there was studied the consumption of fodders (milk; oats; mixed fodders) by experimental calves; dynamics of live weight gain in the beginning and at the end of the experiment; average daily weight gain. Also, there were analyzed the background indexes of blood serum of calves, as well as the indexes of blood serum of calves in a month after application of DKM additive. Research results showed that application of the feed additive DKM promoted better palatability and use of fodders and rendered positive influence on animal productivity. Also, there was marked the normalization of metabolism that was proved y the laboratory tests of blood serum.