What is Cud?

The definition of cud is the partially digested, softened food that ruminant animals bring back up from their stomach to chew again. This process allows them to physically break down tough plant fibers more thoroughly, which helps increase nutrient absorption during digestion.

Cud also contains saliva, which plays an important role in maintaining a balanced digestive environment. The repeated chewing and saliva production support the health of the rumen’s microbial population, essential for breaking down fibrous feed.

Overall, cud is a key component of how ruminants extract energy and nutrients from diets made mostly of roughage. 

Why Do Cows Chew Their Cud?

Cows chew their cud to help digest their fibrous feed more effectively and maintain a healthy digestive system. According to dairy cow nutritionist Mary Beth de Ondarza, when a cow is chewing her cud, that’s a good sign. It means that she is comfortable, relaxed and eating a good diet with a sufficient amount of long fiber.

How Do Cows Chew Their Cud?

Cows chew their cud by regurgitating partially digested food from their rumen back into their mouth, re-chewing it, and swallowing it again to aid digestion.

Here’s how it works: While fibrous feed like hay is good for cows, they have to break it down quite a bit so the rumen bacteria can digest it. When the cow first eats her feed, she chews it just enough to moisten and swallow it. Then the bacteria in the first section of her stomach, the rumen, get to work softening the feed and fiber. This softened food is called the cud, and it is sent back up to the cow’s mouth, where it is re-chewed before going back down into her stomach to be fully digested. Chewing cud produces saliva which is important for controlling rumen acidity. Too much acid hinders the growth and function of the rumen bacteria, especially those that digest fiber.

Cows need to be comfortable and relaxed to chew their cud, and usually lie down to do it. They can lie down for very long periods of time, not to sleep, but just to chew their cud.

What Animals Chew Cud?

Animals that chew their cud are ruminant animals such as cows, sheep, goats, and deer. This chewing behavior is linked to their unique digestive system. These animals have a specialized stomach with a large fermentation chamber called the rumen. The rumen contains bacteria that break down fibrous feed and convert it into energy and protein.

When these animals eat, they initially chew their food just enough to swallow it. The rumen bacteria then soften and partially digest this fibrous material, producing what is called cud. The cud is regurgitated back into the mouth to be chewed again, which further breaks down the feed and stimulates saliva production. Saliva is important because it helps control rumen acidity, maintaining a healthy environment for the bacteria that digest fiber.

Most ruminants spend anywhere from 6 to 8 hours a day chewing their cud, although this varies by species, diet, and health. Specifically, cows tend to chew their cud for about 7 to 8 hours daily, often divided into several sessions throughout the day.

Health Benefits Of Chewing Cud

Cud-chewing cows are generally healthier. With a well-functioning rumen, cows will digest more of their diet and produce more milk. That’s why farmers pay close attention to whether or not their cows chew their cud, and some have even installed monitors to help them keep an eye on the herd’s cud-chewing activity.