What is enteric fermentation?

The rumen: One of the most efficient fibre decomposing systems

The rumen first evolved 50 million years ago, giving mammals access to plant foods they would other not be able to digest.

The rumen is the first and largest part of the multi-chambered stomach of grass eating ruminant animals.  It acts as a fermentation vat where microbes break down plant cellulose into smaller compounds that deliver energy to the animal. This process is known as enteric fermentation.


Inside the anaerobic (oxygen starved) conditions of the rumen, a complex and highly apated microbiome has evolved that includes different types of microbes:

  • bacteria
  • archaea
  • fungi
  • protozoa

The majority of these microbes live in symbiosis with the ruminant animal. The microbes partially ferment the feed which generates energy for themselves and delivers volatile fatty acids, water soulable vitamins and high quality proteins to the animal. In turn, the animal host maintains oxygen free conditions in the rumen and provides an ideal environment for the microbes to thrive.

P44129 - Rumen function diagram FA.jpg

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