Effects of sel-plex (organic selenium) and vitamin E on performance, immune response, and beef cut shelf life of feedlot steers

Several experiments were designed to evaluate the differences of vitamin E level and selenium source on animal performance, selenium plasma concentrations, carcass characteristics, beef retail display, sensory characteristics, colostrum and milk components, and immunity in ruminants. Steers receiving organic Se responded with an improvement in performance during the first 56 d; however, neither Se source nor vitamin E level affected performance over the entire 103 d experiment. Carcass quality measurements were similar among all treatments; however, cattle supplemented with inorganic selenium and a moderate level of vitamin E responded with an increased loin-eye area. Strip loin steaks from steers supplemented with organic selenium and a moderate level of vitamin E exhibited a higher degree of lean lightness when compared with steaks from steers supplemented with inorganic selenium and a high level of vitamin E for the 7 and 14 d aging treatments. Darker lean muscle was recorded for steers fed inorganic selenium and 500 IU of vitamin E compared with the lean muscle of steers fed organic selenium and 125 IU of vitamin E for the 7, 14, and 21 d aging treatments. The organic selenium treatments showed a higher degree of redness in the lean muscle compared with the inorganic selenium treatments. Steaks from steers supplemented with organic selenium had a higher degree of lean muscle yellowness at 7 d of aging. Neither selenium source nor vitamin E level influenced Warner Bratzler shear values. Organic selenium and 125 IU of vitamin E slowed the rate of oxidation of steaks aged 7 and 14 d when compared with inorganic selenium and 500 IU of vitamin E. Organic Se resulted in a greater colostrum selenium concentration compared to inorganic selenium and the control treatments; however, no differences were observed in milk Se concentration among treatments. Neither selenium source nor supplementation influenced milk components, selenium plasma concentration, or immunoglobulins G levels.