The omasum is the third chamber of the deer stomach. Along with the abomasum, it is considered the true stomach. This chamberâ€(tm)s main function in the digestive process is the absorption of water from the mass being passed through.
The omasum, also known as the manyplies, is the third compartment of the stomach in ruminants. Though its functions have not been well-studied, it appears to primarily aid in the absorption of water, magnesium, and fermentation acids. The numerous folds of its mucosa are thought to trap digesta particles to increase their residence time for this said absorption.