The system of digestion of the Ruminantia is very complex and consists of several pre-stomachs and the petrel. The layer or omasum is the third pre-stomach. It is of spherical form of a capacity of several liters. It allows the assimilation of certain nutrients and returns towards the reticulum, the food fermented not enough. He plays in fact the same part as the reticulum. Once the food sufficiently fermented, they passes in the petrel. The layer is not an essential body, it is absent in the pseudo-ruminants. In fact, it is absent at the Chameau X, the LAMA S and the Alpaca S.

External bonds

• On the digestive system of the Ruminant of FAO