Effect of supplemental selenium of performance and deposit of selenium in blood and hair of finishing beef cattle.

Two experiments were conducted to study the effect of supplemental selenium at levels of 0, .1, .2, or .4 mg/kg to a finishing beef catt le diet containing .08 mg/kg. In one experiment, an increase (P<.05) in gain was obtained from adding .1 mg selenium per kilogram. However, in a second experiment, no benefit was obtained from adding .1 mg/kg and supplemental levels of either .2 or .4 mg/kg resulted in a significant depression in rate of gain, indicating the range between sub-optimal and possible growth-depressing levels of dietary selenium for beef cattle may be quite narrow. Selenium levels in whole blood, serum or hair reflected levels of dietary selenium. (