Biofuel co-products as livestock feed - Opportunities and challenges

Co-products from biofuel production for farm animals – an EU perspective 211TABLE 1Composition (g/kg dry matter unless stated) of distillery co-products (fresh and dried) of various originsSource of co-product Water (g/kg) Crude proteinCrude fat(Ether extract)Crude fibre N-free extractives AshCereal grains,unspecified, dried75 235 75 134 415 66Maize grain, fresh 913 20 9 8 45 5Dried 86 285 107 102 401 22Molasses, fresh 922 19 – – 40 19Rye grain, fresh 922 17 4 7 46 4Dried 100 165 82 162 478 13Potatoes, fresh 943 12 1 6 31 7Dried 100 243 37 95 408 117Source: Kellner, 1905.TABLE 2Mean digestibility coefficients (ranges in parentheses) of distillery co-products for ruminants and pigsSource of co-product Organic matter Crude proteinCrude fat (Etherextract)N-free extractCrude fibreRuminantsCereals grains, general 0.710(0.600–0.810)Maize grain 0.690(0.660–0.720)Rye grain 0.570(0.450–0.680)0.640(0.490–0.800)0.640(0.610–0.670)0.590(0.520–0.650)0.940(0.920–0.940)0.930(0.910–0.950)0.620(0.600–0.640)0.800(0.540–0.850)0.700(0.700–0.710)0.490(0.440–0.540)0.610(0.410–0.920)0.670(0.640–0.700)0.500(0.370–0.620)PigsCereal grains, general 0.580 0.780 0.560 0.510 0.360Source: Kellner, 1905.the same author calculated the composition of DGS. Inhis famous textbook The Nutrition of Domestic Animals,Kellner (1905) summarized the composition (Table 1),digestibility (Table 2) and starch units for different co-productsof ethanol production.Developments in distilling technology with consequencesfor composition and nutritive value of DGS during thelast century were reported in several scientific publications(e.g. Naesi, 1985; Askbrant and Thomke, 1986),in animal feeding (e.g. Jensen, Falen and Chang, 1974;Firkins, Berger and Fahey, 1985), as substrate for ensiling(e.g. Abrams et al., 1983, Flachowsky et al., 1990) andwere summarized in various textbooks in Germany (e.g.Kling, 1928; Nehring, 1949; Becker and Nehring, 1967;Kling and Wöhlbier, 1983; Menke and Huss, 1987; Jeroch,Flachowsky and Weißbach, 1993).Due to the high demand for liquid fuels throughoutEurope and the decreasing availability of fuels from fossilsources, the production of biofuel, including bio-ethanol,has gained more importance. The increased productioncapacity and the increasing number of large biofuel plantshas resulted in large amounts of DGS. It is unrealistic todistribute large quantities of DGS beyond the immediatevicinity of a biofuel plant. Due to the short shelf life ofDGS, a large proportion is dried and used as dried distillersgrain with solubles (DDGS). The nutritional quality of DGSand DDGS varies considerably, reflecting the variability ofthe feedstocks, the diversity of the production processesand the proportion of solubles that are included in the finalproduct (Belyea, Rausch and Tumbleson, 2004; Losand etal., 2009; Zijlstra and Beltranena, 2009). Intensive researchon the use of distillers grain—mostly maize-based—in livestockhas been conducted in North America over the pastyears (reviewed i.a. by Klopfenstein, Erickson and Bremer,2008; Schingoethe et al., 2009). However, experiments thatexamine the nutritional value of DDGS common in Europe,based on wheat, barley or rye, or mixtures of these grains,are rare (Franke, Meyer and Flachowsky, 2009; Aldai et al.,2010; Meyer et al., 2010; Noblet et al., this volume).Nutritive value and feeding to ruminantsThe chemical composition and energy concentration ofDGS and DDGS from different grains are presented inTable 3. Distillers grain with solubles is high in CP, withconsiderable variation between the different types of grainused in the production process. The highest average CPcontent, 370 g/kg DM, was reported for DDGS producedfrom a mix of 90 percent wheat and 10 percent barley(Franke, Meyer and Flachowsky, 2009; Losand et al., 2009;Meyer et al., 2010). Mustafa, McKinnon and Christensen(2000) reported that the ruminal escape of CP was lowerfor wheat- than barley-based DGS (490 versus 415 g/kgCP). Generally, distillers grain has a relatively high fibre concentration,with highest cell-wall (neutral-detergent fibre –