Effects of Ensiling, Urea Treatment and Autoclaving on Nutritive Value and In-vitro Rumen Fermentation of Rice Straw

The study was conducted to investigate the effects on the in-vitro rumen fermentation characteristics of rice straw of ensiling, urea treatment, and autoclaving . The treatments consisted of untreated rice straw (P1) compared to the ensiling of rice straw using anaerobic conditions for 30 days (P2), treatment with 3% urea solution (P3), autoclaving at 150o C and 1.2 atm for 60 minutes (P4), combination of ensiling with urea (P5), ensiling with autoclaving (P6), and combination ensiling, urea treatment, and autoclaving (P7). None of the treatments showed significant differences in neutral detergent fibre (NDF) or volatile fatty acid (VFA) content, but did produce significant differences (P < 0.05) in dry matter (DM), organic matter (OM), acid detergent fibre (ADF), pH, NH3 , gas production, methane gas, in-vitro dry-matter digestibility (IVDMD) and in-vitro organic-matter digestibility (IVOMD). The ensiling process had no effect on protein value, IVOMD, or methane gas production. Gas production from all the treatment samples was low up to 12 h but increased at 24 h and 48 h of in-vitro incubation. Rice straw samples ensiled in combination with urea (P5) and autoclaving (P6) had the highest gas production at 48 h. Methane gas production was higher (P < 0.05) in P2, P3, P5, and P6 samples than the rest. Overall, this study concludes that the ensiling process can maintain the quality of rice straw, including in combination with added urea and autoclaving.