Prediction of enteric methane emission from beef cattle in Southeast Asia

We conducted a meta-data analysis to develop prediction equations to estimate enteric methane (CH₄ ) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH₄ emissions. Cattle were provided tropical forage or rice straw, with or without concentrates in individual pens equipped with indirect open-circuit head hood apparatus. The simplest and best equation to predict daily CH₄ emission was CH₄ (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R²  = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH₄ energy as a proportion of gross energy intake (CH₄ -E/GEI, J/100 J) was obtained using DMI per body weight (DMIBW, kg/100 kg), content (g/100 g DM) of ether extract (EE) and crude protein (CP), and DM digestibility (DMD, g/100 g); CH₄ -E/GEI = -0.782 (±0.2526) DMIBW - 0.436 (±0.0548) EE - 0.073 (±0.0218) CP + 0.049 (±0.0097) DMD + 8.654 (±0.6517) (R²  = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH₄ emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices.