The rumen is an important organ to animal species that are herbivores such as giraffes, cattle, llamas, and sheep.  It also comes in handy when it comes to studying metagenomics because scientists can easily study it and extract the enzymes and microbes in order to study the genes and proteins in different species of mammals.  In metagenomics, the cow rumen has more base pairs but less gigabases of sequence data compared to the human gut. [1]

The rumen, also known as a paunch (gut), is used to describe an external stomach like area, where ingested food can be digested through microbial fermentation. [1,2] It is in the alimentary canal of most herbivore mammals.  The smaller part of the reticulorumen is the the reticulum, which has a different texture of its lining than the rumen.  Herbivores need the Rumen to digest the plant based food fibers into smaller components.  Since microbial fermentation is the main mechanism for digestion, the rumen needs healthy, anaerobic, and active microbes.  It needs to maintain a certain pH and balance in order to grow microbes to digest the food, if it's not it can disrupt the stability and acidosis can occur.  A yeast culture and sugars can help stablize the pH by maintaining the number of bacteria needed.  Mainly a problem occurs when the animal's diet contains too much fermentable carbohydrates, causing the lactate producing microbes to rise. [1,2]


Figure 1.1 Picture of a sheep's digestive compartments consisting of the reticulum, rumen, omasum, and the abomasum (