PSX-A-3 - Characterization of Short-season Hybrid Corn Stover and Barley Greenfeed Components Through in vitro Digestibility and Methane Production

Abstract: This study compared the nutrient composition, in vitro methane production, and dry matter (DM) and fiber disappearance of barley greenfeed (seed heads, SEED; leaves, BLEAF; and stems, STEM) and short-season high-moisture corn stover (cobs, COB; leaves and husks, CLEAF; and stalks, STALK) to wheat straw (STRAW). Each plant component was analyzed for DM and neutral detergent fiber corrected for organic matter (aNDFom). Plant components were incubated in in vitro batch cultures for 30 h during which total gas production and methane were measured. Incubation residues were analyzed for DM and aNDFom. The aNDFom (% of DM) was different (P< 0.01; SEM = 1.64) amongst treatments: COB (82.1) = STRAW (75.2) = STALK (72.8) = CLEAF (69.4) > STEM (52.5) = BLEAF (50.4) > SEED (39.1). The DM disappearance (% of DM) of barley components was the greatest (P< 0.01; SEM = 1.734; BLEAF = 60.98, STEM = 57.15, and SEED = 56.52), followed by CLEAF (48.15) and STALK (40.47), but STALK did not differ from the least digestible components of COB (37.21) and STRAW (35.82). Disappearance of aNDFom (% of aNDFom) was greatest (P< 0.01; SEM = 1.734) for BLEAF (63.27), then CLEAF (53.40) and SEED (45.65), but the other components (COB = 44.77, STALK = 44.17, STEM = 42.93, and STRAW = 42.57) were lowest and did not differ from SEED. A difference in methane production (mL/g of DM digested) was observed (P< 0.01; SEM = 1.392) in the following manner: COB (52.07) = STEM (51.04) = STRAW (47.88) = SEED (47.43) > BLEAF (40.83) = CLEAF (38.20) = STALK (36.89). These data provide fiber digestibility coefficients and methane production by plant components and confirms that fiber content is inversely related to DM digestibility for barley and corn components at grain harvest.