In the conditions of the Republic of Belarus there was studied the formation of nonspecific protection factors of the first year foals. By a principle of conditional analogues there was generated a group of clinically healthy foals at which monthly from bulbar veins there were taken tests of blood for hematological and biochemical analysis. From the obtained data it was visible, that within the first year of foal life there were taking place the processes of formation of nonspecific protection factors of an organism which were accompanied by a gradual increasing of quantity of erythrocytes, haemoglobin, leukocytes, certain change in the diagramme, and also increasing of bactericidal and lysozyme activity of blood serum. However, at seven-month age there was marked a considerable decrease in number of erythrocytes, leukocytes, concentration of haemoglobin, bactericidal and lysozyme activity of blood serum is marked, in leukogram share reduction of segmented neutrophils, and at the same time, the content of eosinocytes and lymphocytes increased. It testified the decreasing of protective forces of an organism during this period. Consequently, the seventh month in the postnatal period of foal life proved to be the most critical.

Influence of monocalcium phosphate on natural resistance and clinical indexes of blood of breeding bull calves of white-and-black breed was realized in the conditions of the Republic of Belarus. Bull calves of the first (control) group in the composition of their main ration were fed with mixed fodder K-66-b, hay, green mass and as a balanced phosphoric-potassium additive they were fed with8 grams of defluorinated phosphate per 1 kg of mixed feed. Bulls of the second, third and fourth experimental groups in combination with the standard ration instead of difluoridated phosphate were fed with 5; 10; and 15 grams monocalcium phosphate per 1 kg of combined feed, respectively. Research results showed that application of fodder monocalcium phosphate in addition to the main ration made it possible to increase calcium and phosphorus content in blood of experimental bull calves. In the control group phosphorous content was 2,17 micromole, in the experimental groups – 2,40-2,78 micromole; calcium content – 2,50 and 2,58-2,88 micromole, respectively. The analyzed additive rendered positive effect on protein exchange, increased the natural resistance, bacterial growth-inhibitory activity in blood serum in the third, fourth and second groups on 50,3%, 42,5%, and 40,3%, respectively; lysozyme activity – on 46,0%, 39,2%, and 32,3%, respectively; phagocytic activity of leukocytes – on 21,9%, 25%, and 19,1%

Determination of adaptation and compensation abilities of larval forms of cestodes (cysticercus and echinococci) was realized by means of evaluation of biochemical composition of their internal environment. There was realized the following estimation of biochemical composition of internal environment: Cysticercus tenuycollis from sheep - 34, Cysticercus tenuycollis from swine - 17, Echinococcus granulosus L. from swine - 23. Estimation of biochemical composition of custodies larvaceous forms was realized on the basis of the standard veterinary methods. Research results revealed that osmotic volumetric concentration of internal environment of custodies larval forms was lower than of osmolarity of blood serum. The average value of osmolarity of blood serum for both sheep and swine was 296,63 mmol/l. Research results showed presence of large quantity of specific lipo- and glycoproteins in custodies larva forms. Cysticercotic liquid administrated into suspended matter of microorganism Micrococcus lysadeicticus and leads to lyzing up to 5% of microbal bodies. It was possible to testify the presence of lyzing activity in liquid of larval forms of cestodes. The research results showed that the analyzed larval forms of cestodes had a lot of different and strong defense mechanisms. Adaptation and compensation abilities of larval forms of cestodes had nonspecific character and contained the following: physical mechanisms; humoral immunocompetent factors; and biochemical adaptation