During grazing, ruminants produce large amounts of saliva – estimates range from 100 to 150 litres of saliva per day for a cow. The role of saliva is to provide ample fluid for rumen fermentation and to act as a buffering agent. Rumen fermentation produces large amounts of organic acids, thus maintaining the appropriate pH of rumen fluids is a critical factor in rumen fermentation. After digesta pass through the rumen, the omasum absorbs excess fluid so that digestive enzymes and acid in the abomasum are not diluted.