Strategic use of naturally selenium-rich milling coproducts to manage selenium deficiency in range ewes and their lamb

Authors: Taylor, Joshua - Bret

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2009
Publication Date: 7/8/2009
Citation: Taylor, J.B. 2009. Strategic use of naturally selenium-rich milling coproducts to manage selenium deficiency in range ewes and their lamb. Joint Abstracts of the American Dairy Science and Society of Animal Science. 87(Suppl.2):561.

Interpretive Summary: Selenium (Se) is essential for sustaining a healthy life. When dietary Se was marginally deficient, populations experienced impaired reproduction and growth rates and increased disease rates. Selenium-rich grains, harvested from regions with seleniferous soils, are natural sources of bioavailable Se. Based on our research, Se-enriched feeds can be prepared from high-Se grains that were harvested from regions with seleniferous soils. These feeds were strategically and safely used to eliminate the risk of Se deficiency in livestock while simultaneously creating Se-rich food products, such as meat and milk, for human consumption.

Technical Abstract: The objective was to strategically use Se-enriched wheat milling coproducts to enhance the long-term Se status of range ewes and their offspring. A complete randomized design experiment was used to test the null hypothesis that early lactation diets formulated with Se-rich wheat milling coproducts will not alter the Se status of lactating ewes and their lambs. Mature Columbia-Polypay cross ewes (n = 28; BW = 76.9 +/- 1.9 kg) with twin lambs were placed in individual treatment pens 6 h after parturition. Selenium treatments were assigned randomly to each ewe. Treatments were adequate or elevated dietary Se. The adequate-Se treatment was fortified with sodium selenite to provide 0.020 mg of Se/kg of BW/d, DM basis. The elevated-Se treatment was formulated with Se-rich wheat middlings to provide 0.110 mg of Se/kg of BW/d, DM basis. Treatments commenced when ewes were placed in treatment pens and continued for 19 d. Ewe feeding and watering receptacles were placed out of reach of the lambs; thus, the lambs’ nutrition was restricted to their dam’s milk. Milk samples were collected at 18 d of treatment. Skeletal muscle samples were collected from anesthetized ewes and lambs at the end of the 19-d treatment period, and 108 d later. Muscle and milk samples were analyzed for Se (inductively coupled plasma mass spectrometry). The following data are least squares means with SEM in parentheses. Muscle Se was greater (P < 0.04) in elevated-Se than in adequate-Se ewes; muscle Se (DM basis) was 0.88 and 0.46 (0.04) mg/kg at the end of the treatment period and 0.49 and 0.38 (0.04) mg/kg 108 d later, respectively. Milk Se was greater (P < 0.001) in elevated-Se than in adequate-Se ewes; milk Se was 0.53 and 0.06 (0.03) mg/L at the end of the treatment period, respectively. Muscle Se was greater (P < 0.001) in lambs nursing elevated-Se ewes than in lambs nursing adequate-Se ewes; muscle Se was 2.96 and 0.43 (0.07) mg/kg at the end of the treatment period and 0.74 and 0.25 (0.02) mg/kg 108 d later, respectively. Through strategic use of Se-rich wheat coproducts, skeletal muscle in ewes and their lambs were simultaneously enriched with Se within a 19-d period. Selenium enrichment remained significant for 108 d. This information will enable livestock producers to utilize Se-deficient rangelands for extended periods of time without having to provide supplemental Se.