The Digestive System of Ruminants
Stomach of a ruminant

The goat belongs to a group of animals called ruminants that have a 4 compartment stomach and a unique ability to digest roughages containing relatively large amounts of cellulose. Cellulose is the chief part of the cell walls of plants and a potential source of energy for ruminant animals. The digestive system of ruminants contains millions of bacteria and protozoa that can digest and manufacture a variety of nutrients.

The goat has a four-compartment stomach: rumen, reticulum, omasum and abomasum ( See Fig. below). The rumen is the largest stomach representing about 80% of total stomach area. It is the main site of fermentation. Bacteria and protozoa provide enzymes that can break down fiber and other parts of ingredients. Volatile fatty acids, a major source of energy to ruminants, are produced and absorbed there. Rumen microbes can also manufacture most of the vitamin B Complex, vitamin C and vitamin K. Bacteria and protozoa themselves are sources of protein (microbial protein) for the animal. The reticulum is the “honey comb” or second stomach. It is located below the entrance of the esophagus to trap any heavy metals entering the rumen: it is also called the hardware stomach. The omasum is the third stomach. It has many hanging layers of tissue, which gives it the name “many plies.” The major function of the omasum is absorption of water. The abomasum is the true stomach. It contains acid and enzymes that break down feed material just as in single stomach animals.

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