The objective of the paper was to test efficiency of feed ration enriched with calcium, phosphorus salts and fat concentrate for elimination of negative impacts of magnesite light ashes in beef bulls kept in an exposure area of magnesite works. For this purpose, 24 animals received a feed mix fortified with dicalcium phosphate at a rate of 100 g per head/day for eight months (P1 group) and another group of 24 bulls were administered a feed mix with an addition of 8% corn fat concentrate (P2 group). The other 24 animals were control (control group K). The clinical picture involved the occurrence of mild to profuse diarrheas which were alternately characteristic of all animal species in the first two months of the trial. Feed intake of the investigated groups was equal. Supplementation of feed ration with dicalcium phosphate and corn concentrate increased the weight gains of experimental animals in comparison with control bulls, the increase being 13.2 and 24.5%, resp. In comparison with the control bulls, the intake of the above supplements did not basically influence the dynamics of hematological profile indicators in the experimental bulls (Figs. 1-4). As for the parameters of hepatic profile, in the 3rd month of testing AST activity was positively influenced in both experimental groups if compared with the control group (P < 0.01), Fig. 5, and at the end of observation ALT activity in P2 group (P < 0.01), Fig. 6. Bilirubinemia dynamics did not change in the investigated groups after administration of either supplement (Fig. 9). ALP activity maintained statistically insignificantly higher values in the control animals in the second half of the trial, which demonstrated impairment of mineral metabolism in this group (Fig. 8). Significant differences in IgC levels between the control and experimental groups were confirmed in the 3rd month of the trial (P < 0.01), Fig. 12. In comparison with the control animals, the effect of dietary dicalcium phosphate supplementation in the experimental group P1 and dietary fat extract supplementation in the P2 group was observed in Ca, P and Mg concentrations to a more significant extent in the examined organs as well as in blood serum (Tabs. I-V). Except in spleen, there was a trend of higher cumulation of Ca in all the examined organs of bulls receiving dicalcium phosphate supplement. Phosphorus cumulation showed the same dependence upon dicalcium phosphate intake in the examined organs. Mg deposition in all examined organs showed minimum differences between the experimental groups and control animals.(ABSTRACT TRUNCATED AT 400 WORDS)