In vitro production of methane with increasing levels of corn- or wheat-based dried distillers' grains with solubles in a barley silage-based diet

Abstract Methane production from wheat- or corn-based dried distillers' grains with solubles (CDDGS, WDDGS) was compared in vitro. Wheat DDGS (49 g fat/kg dry matter [DM]) or CDDGS (115 g fat/kg DM) partially or completely replaced whole-crop barley silage at 200, 400, 600, 800 or 1000 g/kg DM. Production of CH4 increased linearly and quadraticly (p<0.01) with increasing levels of CDDGS. Cumulative CH4 production at 24 h was higher (p<0.05) for WDDGS (12.0±0.5 mg/g DM) than CDDGS up to 800 g/kg DM. Molar proportions of propionate in incubation fluid were higher (p<0.05) for CDDG than for WDDGS at 200, 400 and 600 g/kg DM, respectively. In vitro CH4 production (mg CH4/g DM; mg CH4/g digested DM [DMD]) was lower for CDDGS than WDDGS up to 800 g/kg substrate DM. The higher residual oil content in CDDGS compared to WDDGS likely elicited this response.