No abstract

Although the essentiality of selenium (Se) has been known for five decades, the most effective method of Se delivery to cattle is unclear. Se may be administered as an injection or in feed and mineral supplements, with Se usually provided as inorganic sodium selenite. One limitation of inorganic Se is the apparent short duration of Se storage in the body. Natural Se sources in plants are organic forms, namely selenomethionine, selenocysteine, or Se-methylselenocysteine. Organic Se accumulates in muscle as selenoproteins, and subsequently becomes available during dietary inadequacy or during stress conditions when the Se requirement is increased but feed consumption is decreased. Agronomic biofortification is defined as increasing the bioavailable concentration of an essential element in edible portions of crop plants through the use of fertilizers. The purpose of this study was to evaluate Se status in beef cattle after short-term exposure to high-Se-fertilized forage vs a commonly used mineral supplement containing inorganic sodium selenite.