EB1607 Selenium Related Disorders in Washington Livestock. N.L.Gates and K.A. Johnson. Selenium is an essential mineral for growth, reproduction, and disease prevention in all animals. Selenium deficiencies are common in Washington livestock because most Washington soils are moderately to severely deficient in selenium, so the forage for livestock is also selenium deficient. This guide discusses the importance of selenium in cattle and other livestock diets, ways to check for selenium deficiency, selenium responsive diseases, and methods of supplementing selenium in livestock diets. A table lists major clinical signs of selenium responsive diseases in cattle and sheep. Revised June 1995. 2 pages. $1.00.