The grass-eating animals quickly swallow the grass. They then store it in a part of the stomach called [[1]]

The grass-eating animals quickly swallow the grass. They then store it in a part of the stomach called the rumen.

Ruminants, such as cows, sheep, and goats, have a four-chambered stomach, which allows them to digest tough and fibrous plant material such as grass efficiently. 

The rumen is the first compartment of the stomach and functions as a fermentation vat where bacteria and other microorganisms break down the grass. 

To continue the digestive process, partially digested material is regurgitated, re-chewed, and swallowed.