CLINICOBIOCHEMICAL ASPECTS OF MAGNESITE F LUE DUST STRESS IN HEIFERS

The objective of the paper was to investigate clinical and laboratory findings in heifers subjected to magnesite flue dust stress. A 50-day experiment was conducted in clinical conditions on five two-year heife rs of the Slovak and Red Pied breeds at the live weight of 331 to 420 kg. All animals received dietary Mg from the source of magnesite flue dust at a rate of 500 mg/kg live weight. The test flue dust came from dust separation from electrostatic filters and contained these main el ements: Mg (88%), Ca (1.6%), K (0.36%), Na (0.26%), Fe (1.89%), Zn (0. 0026%), Cu (0.000294%) and trace amount of P. The clinical health of t he animals was evaluated daily. Samples of blood, urine and dung were taken before the first administration of flue dust, on days 12, 30 and 50 of the experiment. The counts of erythrocytes, leucocytes, hemoglo bin concentration and hematocrit value were determined in blood. Enzym e activities (AST, ALT, GMT), concentrations of total bilirubin, album in, total proteins and total immunoglobulins were determined in blood serum. Contents of Mg, Ca, P, K, Na, Fe, Cu and Zn in blood serum, uri ne, dung and of the test pollutant were determined by atomic absorptio n spectrophotometry on a Perkin Elmer apparatus (model 306, 1100). Pro fuse diarrhea was a dominant clinical symptom in the animals which app eared in individual animals between 24th and 48th hour from the first intake of magnesite flue dust. Diarrhea lasted alternately in all heif ers until day 50 of the experiment. As for the analyzed parameters of hematological profile during administration of the pollutant (Figs. 1 - 4), Hb and Hk (P < 0.01) increased significantly in the investigated animals on day 12 in comparison with the initial values. Out of the e nzymes, AST and ALT activities showed most readily the feeding of magn esite flue dust (r = 0.99 and r = 0.92, resp.), Figs. 5 and 6. Correla tion relationships between magnesite pollutant administration and bili rubinemia dynamics during the experiment indicated the correlation r = 0.53 (Fig. 8), r = 0.36 (Fig. 9) for total proteins, r = 0.75 (Fig. 1 0) for albumin and r = 0.93 (Fig. 11) for total immunoglobulins. In co mparison with the initial values, Mg concentrations in blood serum and dung significantly increased from day 12 of experiment (P < 0.01 - Fi g. 13) and in urine from day 30 (P < 0.05). Mg intake from magnesite f lue dust negatively influenced Ca, P, K, Na, Fe, Cu and Zn metabolism in the experimental animals. As shown by correlation analysis, magnesi te load in the heifers was demonstrated most objectively by concentrat ions of Mg in urine (r = 0.96) and blood serum (r = 0.95), Ca in urine (r = 0.86) and dung (r = 0.84), P in urine (r = 0.96) and blood serum (r = 0.95), K in urine (r = 0.65) and dung (r = -0.58), Na in urine ( r = 0.91) and blood serum (r = 0.86), Fe in blood serum (r = -0.77) an d dung (r = -0.62) and Cu and Zn in blood serum (r = 0.81 and r = 0.33 , resp.).