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.

In the conditions of the Republic of Belarus there was studied the pathology and biology of cattle capillariasis. Capillariosis invasion rendered a substantial invasion on blood morphological composition which was revealed in lowering of erythrocytes and hematoglobulin, as well as in increasing of leukocytes quantity. There was noted the lowering of the natural resistance and immune reactivity. There were stated substantial deviations in protein metabolism which was expressed in lowering of total protein, quantity of albumins, changing of albumin and globulin coefficient, increasing of globulins. In the conditions of blood biochemical analysis of infesrated animals there was stated a disorder of vitamin and mineral metabolism; increasing of alanine aminotransferase and aspartate aminotransferase enzymes activity. Development of Capillaria bovis was realized in a direct line. In the natural habitat development of Capillaria bovis eggs varied from two up to three months.

In the conditions of the Republic of Belarus there were determined types of transferrins of 46-day old broiler chickens and their relation with indexes characterizing ferrum transport fund. In broilers of Smena-2 cross there were stated four transferrin phenotypes, which revealed at a electrophoregram in a form of two fractions with various mobility and intensity. The quantity of the found out phenotypes should be considered as a minimum one because it was possible to find out the infrequent forms only after realization of a very big number of research studies (for example, occurrence of some phenotypes can be 1:1000 and even lower). Perfection of electrophoresis techniques or application of other carriers (for example, polyacrylamide gel) can also increase a number of phenotypes owing to high resolving power and division of homogeneous transferrin fraction into several sub-factions. The type of transferrin actually did not render influence on the content of haemin proteins, while the indices of ferrum transport fund showed out such kind of dependence. Taking into account that total iron binding capacity (TIBC) was caused by transferrin presence in blood serum, the distinction in this indicator characterized both the transferrin content, and its transport possibilities in relation to iron. The highest content of total iron and TIBC was observed at a slow phenotype of CD tranferrin type (formed by fractions with the least mobility). Fast type of tranferrin АВ (formed by the most mobile fractions) had high enough content of the totaliron but possessed the least iron-binding ability that specifies to the worst performance capabilities of transportation of iron ions. Taking into consideration the transferrin value in formation of antibacterial immunity, it is possible to assume, that broilers with phenotype СD should be more resistant to infections.