Nutrient Value and Digestibility Variation of Five Rice Straw Cultivars in Indonesia as Ruminant Roughage

Five rice straw cultivars in Indonesia (Atomita 1, Bestari, Inpari Sidenuk, Situ Gintung and Ciherang) were investigated for nutrient and in vitro digestibility as ruminants roughage. Except Ciherang, all cultivars were mutant rice variety. This study aimed to: 1) assess the influence of variety on the nutrient and fiber variation of rice straw; 2) predict the nutrient value of rice straw using fiber content; and 3) evaluate the in vitro digestibility of five rice straw cultivars in Indonesia. Except for acid detergent lignin (ADL) (P= 0.09), a significant difference (P<0.05) were observed for all nutrient and fiber contents between all varieties. Acid detergent fiber (ADF) and cellulose content in mutant varieties were significantly higher than Ciherang variety. Based on fiber content, the range in relative feed value (RFV) varied by 60.99 – 68.89. However, all rice straw varieties are included in reject forage class. There were significant differences at 48 and 72 h in vitro gas production (P<0.05) between all varieties. Highly significant differences (P<0.001) were observed for optimum (a+b) and rate gas production (c) traits. The in vitro organic matter digestibility (IVOMD) varied from 30.30 – 35.87%. Those results could explain differences in nutritional quality and digestibility of rice straw according to cultivars. Ciherang variety had a good prospect for ruminant roughage due to the highest nutrient value and digestibility