Recently a group was visiting our farm and one of the tour participants asked, “Do cows really have four stomachs?” The answer is sort of.
Cows are ruminants, which means their stomach contains four compartments: the rumen, reticulum, omasum and abomasum. Ruminants digest their food in two steps. First they eat the feed, than they regurgitate the partially digested food and chew it again in the form of cud.
The four stomach compartments work together;
- The rumen has the capacity to store and process up to 50 gallons of food at a time. The feed material remains here until it has been broken down. Good bacteria in the rumen help the cow digest her food and provide her with protein. This is where cud comes from.
- The reticulum works with the rumen to mix and circulate the undigested feed preventing the rumen from becoming clogged.
- The omasum is where the food goes after it has been broken down. The omasum serves as a pump to move the food from the rumen/reticulum area to the abomasum.
- The abomasum is like a human stomach and is where digestion occurs.
Ruminants eat rapidly and do not chew their food completely before swallowing it. The liquid part of their food enters the reticulum first, while the solid part of their food enters the rumen where it softens. Bacteria in the rumen break it down as a first step in digestion. Ruminants later regurgitate it into the mouth where they chew their cud. The chewed cud goes directly into the other chambers of the stomach, where various microorganisms assist in further digestion.
These stomach chambers allow cows to efficiently turn feed into milk. Ruminants chew their cud approximately 8 hours each day. Research shows that cud chewing is a sign of cow comfort and health. A comfortable, healthy, happy cow chews her cud. That’s why it pleases us to observe our cows chewing.
The rumen’s function is essential for optimal digestion and absorption of nutrients from the feed. This results in healthy cows and good milk production.
Other ruminants include goats, sheep, alpacas, llamas, deer, bison, water buffalo and giraffes.