Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2003
Publication Date: April 15, 2004
Citation: Lawler, T.L., J.B. Taylor, d, J.W. Finley, and J.S. Caton. 2004. Effect of Supranutritional and Organically-bound Selenium on Perfomance, Carcass Characteristics, and Selenium Distribution in Finishing Steers. J.Anim. Sci. 82:1488-1493. Interpretive Summary: Some regions of the United States produce livestock feeds (wheat and hay) naturally high in selenium (greater then 6 ppm). Selenium supplementation in cattle is allowed only up to 0.3 ppm as sodium selenite or selenate. Therefore, the objective of this study was to determine the effects of selenium supplementation, in the form of high Se wheat, high Se alfalfa/grass hay, or sodium selenate, on production, carcass characteristics, and Se distribution and concentration in tissues of finishing beef steers. No negative effects were noted on production or carcass characteristics, with the greatest increases in tissue selenium measured in the high selenium wheat and hay treatments. These results reveal a potential market for feeds naturally high in selenium (wheat and hay) and an effective method to create a beef product that is naturally high in selenium.
Technical Abstract: Dietary selenium influences the Se content in edible muscle of beef cattle. Limited data are available to describe the effects that feeds naturally high in Se have on production, carcass characteristics, and Se distribution in terminal tissues. Therefore, 43 crossbred steers (BW = 351 ± 24 kg) were stratified by BW and assigned to one of four dietary treatments: Se adequate (CON; n = 12), Se provided as high-Se wheat (WHT; n = 9), high-Se hay (HAY; n = 11), or sodium selenate (SEO; n = 11). Daily selenium intake for WHT, HAY, and SEO diets was 65 µg/kg BW, whereas it was 9.5 µg/kg BW for CON. Diets were similar in ingredient composition (25% wheat, 39% corn, 25% grass hay, 5% desugared molasses, and 6% wheat middling-based supplement; DM basis), isonitrogenous and isocaloric (14.0% CP, 2.12 Mcal NEm/kg DM and 1/26 Mcal NEg/kg DM) and offered once daily (1500) individually to steers in a Calan gate system for 126 d. At the end of the tria, steers were slaughtered; carcass data were recorded; and samples of the liver, kidney, spleen, semitendinosus, and hair were collected for Se analysis. Intake of DM, G:F, ad ADG did not differ (P > 0.13). No differences (P > 0.12) were noted for hot carcass weight, organ weights, longissimus muscle area, backfat thickness, marbling scores, or quality and yield grade. Kidney, pelvic, and heart fat tended to be higher (P = 0.06) in CON and WHT compared with SEO and HAY steers (2.9, 2.4, 2.5, 2.9 ± 0.2% for CON, SEO, HAY, and WHT, respectively). Selenium concentrations in all tissues collected differed (P < 0.003) due to treatment. Distribution of Se to the kidney, spleen, and hair were similar with CON < SEO < HAY < WHT (8.40, 10.05, 10.86, 12.89 ± 0.26 ppm for kidney; 2.00, 2.60, 3.82, 5.16 ± 0.09 ppm for spleen; 1.80, 4.00, 5.93, 10.54 ± 0.56 for hair; P < 0.01). The distribution of Se in liver and muscle (DM basis) differed from that in other tissues, with CON < HAY < SEO = WHT (2.33, 6.56, 9.91, 10.79 ± 0.80 ppm; P < 0.01) and CON = SEO < HAY < WHT (1.33, 1.55, 3.32, 4.41 ± 0.18 ppm; P < 0.01), respectively. When providing dietary Se at supranutritional levels, source of Se did not affect production or carcass characteristics, but it altered the distribution and concentration of Se throughout the tissues of finishing beef steers.