Ruminant Stomach -
The stomach of ruminants is compound due to the presence of four chambers - rumen, reticulum, omasum and abomasum.

Storage of food occurs in rumen (rumen is the largest chamber).

True stomach is the abomasum where secretion of gastric juices occurs.

Anaerobic cellulolytic bacteria (eg. Rumenococcus) and Protozoans reside in rumen and reticulum and secrete cellulase for the fermentation of cellulose.