Blood selenium levels during different stages of selenosis in buffaloes and its evaluation as a diagnostic tool.

Selenium (SC) toxicity was experimentally induced in male buffalo calves following repeated oral administration of 0.3 mg selenourea/kg (providing 0.19 mg/Se kg) for 75 d. On the basis of the major toxic effects produced in the experimental animals, 10 additional clinical cases of selenosis were identified from field cases. In experimental selenosis blood Se increased from 0.70 +/- 0.08 microg/ml on day 0 to 3.12 +/- 0.01 microg/ml on day 75. Hair Se rose from 2.42 +/- 0.6 ppm on day 0 to 22.91 +/- 2.6 ppm by the 11th w. The erythrocyte glutathione peroxidase (GSH-Px) activity increased from 5.35 +/- 0.94 Eu/mg Hb (0 day) to 18.81 +/- 0.46 EU/mg Hb in the 11th week. Blood Se was of better diagnostic value than hair Se or erythrocytic GSH-Px activity. Signs occurred when Se levels were about 2.0 microg/ml and were prominent above 2.5-2.6 microg/ml: Se levels > or = 1.5-1.75 microg/ml were diagnostic of impending selenosis. The Se concentrations in blood from the field cases of Se toxicity in buffalo had excellent correlation with Se levels in the experimental cases.