Although a cow has no upper front teeth, it grazes up to 8 hours a day, taking in about 45 kg (100 lb) of feed and the equivalent of a bath tub full of water. A healthy cow gives about 200,000 glasses of milk in her lifetime.
A cow has four stomachs: the rumen, reticulum, omasum and abomasum. The rumen is the largest stomach and acts as a fermentation chamber. The abomasum is last of the four and is comparable in both structure and function to the human stomach.