When a cow first takes a bite, it chews just enough to moisten the food. Once swallowed, the food goes into the first section, the rumen, where it mixes with other acidic digestive liquids and is softened. The softened food is called cud, small balls of food.
Next, the rumen muscles send the cud back up to the cow’s mouth, where it is re-chewed and swallowed again, this time going to the Omasum section of the stomach in order to squeeze out all of the moisture.
Finally, the food enters the last part, Abomasum of the stomach where it mixes with digestive juices and makes its way to the intestine to be completely digested.
Cud chewing is often used as an indicator of a healthy and comfortable herd. A happy, healthy animal will produce more milk or have a higher production of muscle.