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).
United Nations Framework Convention on Climate Change (UNFCCC), Updated UNFCCC reporting guidelines on annual inventories following incorporation of the provisions of decision 14/CP.11. 2006.
Available online at: http://unfccc.int/resource/docs/2006/sbsta/eng/09.pdf
Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories: Reporting Instructions. Section 1.1, "Source/sink categories."
Available online at: http://www.ipcc-nggip.iges.or.jp/public/gl/guidelin/ch1ri.pdf