Definition of 4A Enteric Fermentation Source Category
Methane production from herbivores as a by-product of enteric fermentation, a digestive process by which carbohydrates are broken down by micro-organisms into simple molecules for absorption into the bloodstream. Both ruminant (e.g. cattle, sheep) and non-ruminant animals (e.g. pigs, horses) produce CH4, although ruminants are the largest source (per unit of feed intake).
Intergovernmental Panel on Climate Change (IPCC), Revised 1996 Guidelines for National Greenhouse Gas Inventories. Houghton, J.T., Meira Filho, L.G., Lim, B., Tréanton, K., Mamaty, I., Bonduki, Y., Griggs, D.J. and Callander, B.A. (Eds).. IPCC/OECD/IEA, 1997.
Available online at: http://www.ipcc-tfi.iges.or.jp/public/gl/invs1.html