Cows are ruminant animals.
Their digestive tracts, which are similar to those of goats, sheep and deer, consist of the mouth, oesophagus, four stomach compartments, small intestine and large intestine.
HOW MANY STOMACHS DOES A COW HAVE?
Cows actually only have one stomach, but it has four distinct compartments made up of the Rumen, Reticulum, Omasum and Abomasum. It is very different than a human stomach. That’s why people often say that a cow has four stomachs.
HOW DOES A COW’S STOMACH WORK?
Below is a diagram of the internal digestive system of a cow. It shows the four stomach chambers and the intestines.
1. The Rumen – this is the largest part and holds upto 50 gallons of partially digested food. This is where the ‘cud’ comes from. Good bacteria in the Rumen helps soften and digest the cows food and provides protein for the cow. This compartment, also known as the ‘paunch’, contains many microorganisms (bacteria and protozoa) that supply enzymes to breakdown fibre and other food that the cow eats. The conversion of the cellulose of feeds to volatile fatty acids (acetic, propionic, and butyric acids) is the result of microbiological activities in the rumen. These volatile fatty acids are absorbed through the rumen wall and provide up to 80 percent of the total energy requirements of the animal. Microbial digestion in the rumen is the basic reason why ruminant animals effectively utilize fibrous feeds and are maintained primarily on roughages.
Rumen microorganisms also convert components of the feed to useful products such as the essential amino acids, the B complex vitamins, and vitamin K. Finally, the microorganisms themselves are digested further in the digestive tract.
2. The Recticulum – this part of the stomach is called the ‘hardware’ stomach. This is because if the cow eats something it should not have like a peice of fencing, it lodges here in the Recticulum. However, the contractions of the reticulum can force the object into the peritoneal cavity where it initiates inflammation. Nails and screws can even peroferate the heart. The grass that has been eaten is also softened further in this stomach section and is formed into small wads of cud. Each cud returns to the cows mouth and is chewed 40 – 60 times and then swallowed properly.
3. The Omasum – this part of the stomach is a ‘filter’. It filters through all the food the cow eats. The cud is also pressed and broken down further. This compartment, also known as the ‘manyplies’, consists of many folds or layers of tissue that grind up feed ingesta and remove some of the water from the feed.
4. The Abomasum – This compartment is more often considered the ‘true stomach’ of ruminant animals. It functions similarly to human stomachs. It contains hydrochloric acid and digestive enzymes that breakdown food particles before they enter the small intestine. Here, the food is finally digested by the cow’s stomach juices and essential nutrients that the cow needs are passed through the bloodstream. The rest is passed through to the intestines and produces a ‘cow pat’.
As partially digested feed enters the small intestine, enzymes produced and secreted by the pancreas and small intestinal mucosa further breakdown feed nutrients into simple compounds that are absorbed into the bloodstream. Undigested feed and unabsorbed nutrients leaving the small intestine pass into the large intestine. The functions of the large intestine include absorption of water and further digestion of feed materials by the microorganisms present in this area.
HOW DOES A BABY COW’S STOMACH WORK?
When a baby calf is born, the rumen is small and the abomasum is the largest of the four stomach compartments. The rumen of a calf represents about 30 percent of the total stomach area, while the abomasum represents about 70 percent.
Hence, digestion in the young cow is like that of a monogastric animal.
In the suckling calf, closure of the oesophageal groove ensures that milk is channeled directly to the abomasum, instead of entering the rumen, reticulum, and omasum. When the suckling calf starts to eat vegetation, the rumen, reticulum and omasum gradually develop in size and function.
What Does a Cow Eat?
Cows are herbivores which means they do not eat meat, only plants, grass and cereal.
How Long does a Cow Eat Each Day?
A cow spends up to 6 hours a day eating. Cows spend over 8 hours a day chewing their cud which is regurgitated, partially digested food. Cows each drink equivalent to a bathtub full of water a day.