1 REDUCTION OF METHANE PRODUCTION FROM BUFFALO HEIFERS FED SOY-SAUCE BY-PRODUCT IN SOUTHEAST ASIA

Eight swamp buffalo heifers (age 1.5 year, weight 160 kg) were fed a basal diet consisted of Napier grass (Pennisetum purpureum sp) and commercial concentrate at a ratio of 70:30. Four of them received the basal diet only (BDO), while the other four were given soybean pulp at amount of 25 % of total concentrate (BD-SP). The buffaloes were adapted to the diets for two months prior to data collection periods. Daily intake of dry matter (DMI), gross energy intake (GEI), methane production and live-weight gain were measured. Methane measurement utilized the facemask method equipped with a methane analyzer (Horiba Ltd., Japan), and was performed for 10 minutes at 3 hour intervals over two days. Results indicated that the methane conversion rate (MCR; CH4 MJ/100 MJ GEI) of the BD-SP-fed buffalo was lower than that of the BDO group (12.0 vs. 10.5), as was the DMI (BD-SP: 4.55 vs. BDO: 4.76 kg/d), and the methane production per kgDMI (31.8 vs 28.7 g/kgDMI). The buffaloes receiving BD-SP had a higher daily gain than those receiving BDO (0.45 vs. 0.35 kg) therefore, the methane production/kg weight gain ratio of BD-SP buffalo was significantly lower (295 gCH4/kg) than that of the BDO buffalo (443). We compared these values to those for cattle in temperate and tropical conditions and to values predicted by a general equation and a tropical-conditions equation. Our results suggest that supplementation by this common Southeast Asian food industry by-product can lead to a significant mitigation of methane in tropical climates