What are recommended levels of selenium in diets fed horses?
NRC suggests 0.1 ppm Se in the total diet for all ages and classes of horses. While most agree that 0.1 ppm Se is sufficient for mature idle horses, requirements for performance horses, growing horses and mares are probably higher – on the order of 3 mg/day. This amount equates to about 0.3 ppm Se in the total diet and is the amount added by many feed manufacturers. Sel-Plex is cleared for addition at 0.3 ppm. Don’t forages and grains contain selenium? Selenium content of forages and grains varies among regions of the country. While a few areas in the northern Great Plains have very high soil selenium content, much of the corn and soy-producing region of the US is low in Se. In general, crops and pasture in the eastern half of the US are low in natural selenium, as are those in the Pacific Northwest. We add selenium supplements to animal feeds to insure adequate intake despite soil and crop variations. Why do horses need selenium? Selenium has several roles, but the most well-known is
