초록
This study was conducted to measure the improvement in nutritive value of rice straw by treatment with urine of goat under different temperatures. Straw samples were japonica I (comprising 15 varieties with culms longer than 123 cm and mean silica content of 13.0%), japonica II (comprising 20 varieties with culms less than 87 cm and mean silica content of 13.7%), indica I (Java 14 variety with a high content of silica of 13.9%) and indica II (comprising IR-8 and IR-20 varieties with a low content of silica of 11.0%). Urine was collected from four Japanese Saanen goats fed alfalfa hay. The different straws were sprayed with urine at the rate of 1 ml/g straw DM, put in double layer plastic bags, sealing and stored for 4 weeks at either $20^{\circ}C$ (GU-20) or $40^{\circ}C$ (GU-40). The in vitro dry matter digestibility (IVDMD) and organic matter digestibility (IVOMD) of the straws were improved by the GU-40 treatment (13.5% and 13.2%, but the GU-20 treatment had little effect of digestibility (1.5% and -0.2%) except with the low silica indica II varieties. The GU-40 treatment tended to decrease NDF and hemicellulose content of straws. Crude protein content of the straws was improved by both the GU-20 and GU-40 treatments. It was concluded that treatment of rice straw with goat urine at $40^{\circ}C$ for 4 weeks improved the crude protein content and digestibility in vitro, the greatest improvement occurring with straws of lowest digestibility in the untreated state.