Effects of calcium oxide treatment at varying moisture concentrations on the chemical composition, insitu degradability, invitro digestibility and gas production kinetics of anaerobically stored corn stover

摘要

The objective of this study was to determine the optimum conditions for calcium oxide (CaO) treatment of anaerobically stored corn stover by insitu and invitro methods. Four ruminally cannulated, non-lactating, non-pregnant Holstein cows were used to determine the insitu effective degradabilities of dry matter (ISDMD), organic matter (ISOMD), neutral detergent fibre (ISNDFD), invitro organic matter disappearance (IVOMD) and gas production in 72h (GP(72h)) of corn stover. A completely randomized design involving a 3x3 factorial arrangement was adopted. Ground corn stover was treated with different levels of CaO (3%, 5% and 7% of dry stover) at varying moisture contents (40%, 50% and 60%) and stored under anaerobic conditions for 15days before analysis. Compared with untreated corn stover, the CaO-treated stover had increased ash and calcium (Ca) contents but decreased aNDF and OM contents. The moisture content, CaO level and their interaction affected (p0.01) the content of aNDF, ash and OM, and the ratio of aNDF/OM. The greatest ISDMD, ISOMD and ISNDFD were observed when stover was treated with 7% CaO and 60% moisture, while no differences (p>0.01) in these insitu degradability parameters were observed between the stover treated with 5% CaO at 60% moisture content and those treated with 7% CaO at 60% moisture content. Corn stover treated with 5% CaO at 50% moisture had the maximum IVOMD and GP(72h) among the treatments, and there was no difference (p>0.01) between 50% and 60% moisture. Results from this study suggested that 5% CaO applied at 60% moisture could be an effective and economical treatment combination.