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 (CH ) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH 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 CH emission was CH (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R  = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH energy as a proportion of gross energy intake (CH -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); CH -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) (R  = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices.