[en] The results of evaluation of sensitivity and adaptive possibilities of the sheep organism by long impact of increased doses of electromagnetic radiation (EMR) of the UV-range in the experiment by clinical-physiological indices modeling the 25 and 50 % depletion of the Earth ozone layer are presented. It is established that the character of changes in the animals organism depends on the irradiation dose sensitivity of the individual living system organism to the EMR and physiological peculiarities of its protection. However, the functional changes in the cardiovascular, immune and reproduction systems, homeostasis system and substance exchange in the period of chronic irradiation do not effect the development of irreversible pathological changes