Differences in Drying Method of King Grass (Pennisetum hybrid) Silage Samples Prepared for in Vitro Digestibility Analysis

Abstract

In vitro digestibility of silage was influenced sample preparation methods because silage contained volatile compounds had potentially losses during preparation. An experiment had been conducted to evaluate different methods for preparing of a silage sample which was used in vitro digestibility studies. King grass (Pennisetum hybrid) silage were sampled at 21 d incubation for in vitro gas production analysis. Sample preparation was conducted by oven drying at 60°C while freeze drying method at -20°C and both of them conducted during 20 hours. The variables measured were in vitro dry matter and organic matter digestibility (IVDMD and IVOMD), gas production, volatile fatty acids (VFA) production. The experiment was arranged on completely randomized design with t-test analysis. Results showed that either IVDMD or IVOMD from silage dried by oven and freeze drying methods were similar. Production of volatile fatty acid (VFA) and acetate: propionate ratio (C2:C3) had also no differences between silage prepared by oven and freeze drying methods. However, total gas production from silage during 48 hours incubation affected by drying methods significantly (P<0.05). Gas production of freeze dried silage (Y) could be predicted by gas production from oven dried silage (X) as followed the equation was Y=1.0846X+0.7947 (R2=0.997). It was concluded that oven drying method could be used for the sample preparing method of silage at the in vitro digestibility analysis.