Lytvynenko V. 3. Beef breeds calf's naturals resistance and immune reactivity to diseases in the conditions of the diff types of keeping.

3. Natural resistance, immune reactivity, adaptation and resistance mechanism, the cell and humoral factors of the protection, infectious diseases. The problems study of natural resistance and immune reactivity of Aberdeen Angus, Limusins and Semmental calf's in the different of system. If was discovered that keeping of the cattle at the open air positively affects оп the cattle resistance to diseases. This affect are choracterured by different displays of the cell and humorals of the protection. The results of the experiment promote this can be the base for developement of the protectial measures for animal keeping and struggle with the infectious diseoses.