Enteric fermentation

Enteric fermentation is fermentation that takes place in the digestive systems of ruminant animals.

It is one of the factors in increased methane emissions.

Ruminant animals are those that have a rumen. A rumen is a special stomach found in cows, sheep, and water buffalo that enables them to eat tough plants and grains that monogastric animals, such as humans, dogs, and cats, cannot digest.

Enteric fermentation occurs when methane (CH₄) is produced in the rumen as microbial fermentation takes place. Over 200 species of microorganisms are present in the rumen, although only about 10% of these play an important role in digestion. Most of the CH₄ byproduct is belched by the animal, however, a small percentage of CH₄ is also produced in the large intestine and passed out as gas.

In Australia ruminant animals account for over half of their green house gas contribution from methane. [Australian Greenhouse Office, "National Greenhouse Gas Inventory", Canberra ACT, March 2007.] Australia has implemented a voluntary immunization program for cattle in order to help reduce flatulence-produced CH₄.

References

Un-cited References

#M. J. Gibbs and R. A. Leng, "Methane Emissions From Livestock", Methane And Nitrous Oxide, Proceedings Of The International IPCC Workshop, Amersfoort, The Netherlands, pp. 73-79, February 1993.
#State Workbook: Methodology For Estimating Greenhouse Gas Emissions, EPA 230-B-92-002, U. S. Environmental Protection Agency, Office of Policy, Planning and Evaluation, Washington, DC, 1995.
#International Anthropogenic Methane Emissions: Estimates for 1990, EPA-230-R-93-010. U. S. Environmental Protection Agency, Global Change Division, Office of Air and Radiation, Washington, DC, 1994.
#P. Crutzen, et al., Methane Production By Domestic Animals, Wild Ruminants, Other Herbivorous Fauna, and Humans, Tellus, 38B(3-4): 271-284, 1986.
#Anthropogenic Methane Emissions In The United States: Estimates For 1990, Report to Congress, U. S. Environmental Protection Agency, Office of Air and Radiation, Washington, DC, 1993.
#Greenhouse Gas Inventory Workbook, Intergovernmental Panel On Climate Change/Organization For Economic Cooperation And Development, Paris, France, pp. 4.1-4.5, 1995.