Ruminants are plant-eating animals like sheep, elk, cows, that have four stomachs for their digestion instead of one like how humans have. They obtain nutrition from plant material by adopting a certain process called rumination. Through rumination, they ferment the food and regurgitate and chew their food before the principal digestion.
For humans, the food goes from the mouth to the food pipe to the stomach to intestines and onward but it’s just a little bit different for the ruminants. There are cows on the roads, streets and outside your house sometimes that are always chewing away to glory. And most often than not, they don’t even have food near them. The diet for these animals includes grass, leaves and different types of plants. These foods have high fiber content. To digest the cellulose in the food they eat, an enzyme called cellulase is required which isn’t produced by the animals themselves. Hence they require help. The stomach of these herbivores is divided into 4 chambers of which the most important one is the rumen.
Ruminants and Four Chambers
Ruminants do not completely chew the food they eat, but just ingest as much they can or want and then swallow the food. This is actually an adaptation by which these animals have evolved to spend as little time as possible feeding so that they aren’t hunted down by any predators while they are eating. They can later go to a safe environment to completely digest the food they have eaten.
From here, the food moves on to the rumen. This is the first chamber of the stomach which also happens to be the largest. The food is stored here for a while and only partially digested, mostly when the animal is resting.
There are some bacteria and microorganisms in the rumen which produce the cellulase required to digest that cellulose which is so hard to process. Once the plant fibers have been broken down to provide vitamins, proteins, and organic acids, the nutrients are absorbed into the animal’s bloodstream. Coarse plants are sent further into the next chamber for further digestion. Here is where the further bacterial action takes place and the food is formed into soft chunks called the cud.
This cud produced is regurgitated back into the animal’s mouth where they can be chewed again. The saliva of the cow greatly aids in digesting the cud. After chewing, the food bypasses the two chambers of the stomach and directly enters the third chamber. The walls of the 3rd chamber mash and compact the food up much further, and then pass it to the fourth chamber – the abomasum. The final digestion of the stomach is done here and then passed to the intestine.
For more detailed information about digestion in Ruminants, visit Byju’s.