The Effect of Cattle Breed and Forage-Concentrate Ratio on Fecal Methane and Nitrous Oxide Emissions

A field experiment was carried out to assess the methane (CH4) and nitrous oxide (N2O) emission from feces of different Indonesian cattle breeds and forage-concentrate ratio. The objectives of this study were to calculate the amount of CH4 and N2O emission and to analyze the effect of different cattle breeds and forage-concentrate ratio on CH4 and N2O emissions. The experiment used 3 x 2 factorial design. The first factor was three Indonesian local cattle breeds (Bali cattle, Madura cattle and Peranakan Ongole cattle). The second factor was two ratios of forage-concentrate (70:30 and 30:70). The gas was collected manually by using the 20 mL plastic syringe on 11 observation days in a month. On each observation day, the gas was collected five times with 10-minute interval (minute 10, 20, 30, 40 and 50 after chamber closure) between 2 and 3 pm. Analysis of variance (Anova) was conducted to analyze the effect of cattle breeds and forage-concentrate ratio. The result showed emission peak of CH4 was on day 0 to 6, while the N2O peak was on day 9 to 15. The highest amount of CH4 emission occurred on feces of Bali cattle with 30:70 forage-concentrate ratio (895 mg CH4/kg/day) on the first day of observation. The highest amount of N2O emission was occurred on feces of Peranakan Ongole cattle with 30:70 forage-concentrate ratio (71,781.62 mu g N2O/kg/day) on day 15. The cattle breed and forageconcentrate ratio had no significant effect on both CH4 and N2O emission from feces.