Results on determination of residual quantities of fenbendazole and its metabolites in cattle meat, organs and tissues after administration of preparation Febolvet in dose of one bolus per one animal realized in the conditions of the Republic of Belarus were presented. Animals were killed in 35 and 80 days after administration of preparation. There were no strangulates in animals organs. Pieces of nephros, liver, cordis, fat and muscle tissue were chosen for residual quantity of fenbendazole and its metabolites evaluation. The level of carcasses bleeding was good at application of boluses of infested activity with fenbendazole. In 24-48 hours of keeping in refrigerator the drying crust was well-defined, muscle tissue in cut had firm texture and from light red to red color, cut areas were wet. Tendon was form and elastic. Soup was clear, flavored and without extraneous odors. Study of physical-chemical indexes estimated peroxidase activity, pH, presence of products of primary breaking of protein in 24 and 72 hours after killing. Biological value decreased slightly (on 1,04%). Veterinary-sanitary evaluation of cattle meat was conducted in the investigation. Research results showed no residual quantities of fenbendazole in the analyzed samples after application of long lasting boluses. Application of the analyzed boluses in case of cattle strongylatosis did not lower the veterinary and sanitary indexes of meat and did not render substantial effect on its quality

Data оn evaluations of therapeutic efficacy of albendazol and fenbendazol agaonst acute and chronic forms of larval cestodiasis of animals were studied in the conditions of the Republic of Belarus by an example of experimentally infested sheep and rabbits. Application of albendazol and fenbendazol both separately and in complex with antioxidant vitamin and mineral additive against the chronic forms of cysticercosis tenuicollis and cysticercosis pisiform was inefficient. But application of albendazol against acute form of cysticercoses caused the lowering of invasion intensity in shepp and rabbits in 3 times, fenbendazol – in 2,6 times. Application of anthelmintic agents in complex with vitamin and mineral composition promoted the lowering of invasion intensity (in 5 and 4,1 times, respectively) and prevented the disease development in 60% of animals.

In the conditions of the Republic of Belarus there was realized a study of age-specific features of level of erythrocytes, haemoglobin in blood, activity of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase, as well as concentration of calcium, phosphorous, magnesium and ferrum in blood serum of suckling colts in the first 6 months of life. In the studied animals there was stated increased levels, haemoglobin and ferrum concentration in blood, but during the 6th month of life the same indexes decreased considerably. The most considerable changes оf blood serum enzymatic activities occurred at the age of 2 and 6 months. Thus, during the 2nd month of life a raise in ALAT, LDH activity, calcium and phosphorus concentration was noticed. At the age of 6 months ALAT and ASAT levels increased, and LDH activity, magnesium and phosphorus concentration decreased. During the first 6 months of life the ALP activity was on a high level and underwent no reliable changes. As the research showed, blood serum enzymatic activity and concentration of calcium, phosphorus, magnesium and ferrum depended on colt age and change at the process of growth and development of animals.

On the basis of the data analysis of morphological and biochemical blood traits it was determined that blood indices of all groups of pigs didn't break the limits of physiological norms. Pigs of Canadian selection differ by high metabolism intensity and immunity of organism