Cows and almost all cattle are ruminants. So what are ruminants? Ruminants are cud-chewing hoofed mammals with a stomach with four and occasionally three chambers. One ruminant is the cow, and you may be wondering why you have only ever seen one stomach for it, and how the number of stomachs can increase. Well, you are technically right. Strictly speaking, the cow has only one stomach. But in reality it is divided into four chambers to form four stomachs. Read on to learn more about the different types of stomachs and the reason for the four-chamber structure.
How Many Stomachs Does A Cow Have?
Unlike humans, the structure of the cow’s stomach varies, which is why it is counted as four stomachs. Let us first look at the parts of the cow’s stomach:
Rumen – It is the first part of the cow’s stomach. This is where the process of breaking down complex food – grass or highly developed plants – takes place.
Reticulum – This is where the cud is produced when the saliva of the cow is combined with the feed. In addition, the cud burps into the mouth, and the cattle chews it down to break it down into fine particles. You may have noticed that the cow is constantly chewing on something that resembles chewing gum as she processes her ruminant food.
Omasum – This is where all the water in the food is absorbed.
Abomasum – Here the food is completely digested, and the process is similar to that which takes place in the human stomach.
The cow’s plate consists of hay silage, distilled grains, maize silage, cereals (maize), soya meal, hay, and wheat.
Rumen And Reticulum
After ingestion, food is lightly chewed and mixed with saliva and after swallowing it is moved through the esophagus in the rumen.
The rumen resembles a vat, as it makes it easier to store food and mix it. It ensures a constant temperature, pH, and anaerobic environment. The region regularly receives well-ground substrates from the esophagus. Fermented products are either absorbed here in the same region or let down through the system.
One of the main functions of the rumen is to live on roughage: shrubs and grasses that are rich in cellulose. The rumen is designed for fiber digestion. It forms the largest part of the mammalian stomach. Sometimes it is also called the “fermenter”. In order to improve the absorption of nutrients and to facilitate the surface, the inner layer of the rumen is lined with papillae and tiny protrusions.
A tissue back separates the reticulum from the rumen. The lining of the tissue appears honeycombed due to the small papillae present here. Both the reticulum and the rumen can hold between 50 and 120 liters of fluid and food. The temperature inside the rumen remains at about 39 degrees Celsius (or fluctuates between 38 and 42 degrees Celsius). It is best suited for a number of microbes to thrive.
Under normal circumstances, the pH of the rumen and reticulum contents is between 6 and 7, and a stable pH is maintained by continuously removing the acidic products of microbial fermentation and by simultaneously adding bicarbonate from saliva.
Rumination Followed By Chewing
Through the mechanical action of chewing, the food is broken down into small particles before it reaches the rumen. In addition, chemical degradation takes place in the rumen with the help of enzymes secreted by the microbes present in the rumen. Through the combination of rumen microbes and liquid, the food components are continuously churned to further simplify the food. The wall of the rumen and reticulum shows contractions, which favors the movement of fine food particles into the next part of the omasum.
Rumination is the process by which the newly consumed food is returned to the mouth for advanced chewing. Advanced chewing breaks down the food into more fine particles, which increases the surface area of the food particles. Consequently, the food becomes easily accessible to rumen chemicals. Consequently, the speed of the microbial digestion is increased.
Depending on the dietary fiber content of the food, the process of chewing cud or ruminating takes some time. If the food is rich in dietary fiber, ruminating takes longer, and if the fiber content is minimal, the ruminant period remains shorter. If the amount of feed is lower, less milk is produced.
While the food remains in the rumen, most nutrients are absorbed through the wall. In addition, absorption supports the movement of food components through the wall to move from the digestive tract into the bloodstream. From the bloodstream, they are transported to the liver.
The process of food flow through the rumen is continuous. Remember that food longer than 1 mm cannot move through the rumen until its length is reduced. Therefore, the rumen is the primary regulator of the ingested food.
Food Passage Through Rumen
Digestion depends to a certain extent on the passage of food in the rumen. In general, the speed of food passage and digestion depends on particle size, density, degree of food intake, and ease of digestion. Few foods pass through the digestive system quickly and easily, while some hard foods take a long time to be excreted.
The omasum occupies the space between the reticulum and the stomach. The output of the reticulum, which enters the omasum, has water as its main component. Let’s say about 90% to 95%. The function of the omasum is to remove the water content from the feed and to digest it further into the fine particles. The omasum has wrinkles that appear large and are called lamellae.
This is the link between the small intestine and the omasum. This is the place of acid digestion and resembles the human stomach. The walls of the abomasum are folded and form grooves that secrete gastric juices, which contain some enzymes and hydrochloric acid. The pH of the region remains between 1 and 1.3, which makes the area acidic. Rumen microbes are killed by the acidity of the area. Enzymes like pepsins carry out the digestion of food protein in the stomach.