The animal kingdom is a fascinating world, not only because of the diversity of species that exist on the planet, but also because each group has specialized in an incredible way to make the best use of the resources with which that counts in the space it inhabits. In this sense we have the cows, vertebrates that belong to the class Mammals, order Artiodactyla and family Bovidae. These are also found in a suborder identified as Ruminantia (ruminants) due to the specific complexity of processing food, which has led to the belief that these animals have several stomachs.
If you have ever wondered about how many stomachs a cow has and how is its digestion process, then continue reading this article from ExperoAnimal, in which we are going to clarify these aspects for you.
What is a ruminant?
Ruminant animals are exclusively herbivorous that feed on stems, grasses and herbaceous materials, possessing a complex digestion system to transform the food into simpler compounds and be able to take advantage of their chemical components, thus being able to nourish themselves. The plants that ruminants feed on are made up of a high content of cellulose, which can only be used thanks to the anatomy of the digestive system of these animals, which also has specialized microorganisms that contribute to the process.
Ruminating properly consists of chewing again the food that had already been swallowedIn this sense, these animals mix with saliva and lightly chew the food and pass it to the esophagus so that it is then carried to the stomach. But in this process, the larger particles are regurgitated into the mouth to be re-chewed and then re-ingested.
Digestive system of cows
Cows can consume on average about 70 kg of grass per day, within 8 hours, which represents a high amount of mass that, together with the difficulty to process and assimilate this type of food, means that these animals require a peculiar anatomical and physiological system to carry out the digestion process.
The cow's digestive system is made up of:
- Mouth: in which the tongue and teeth are located. The tongue is made up of different papillae that give it its rough texture and it is long, since it has an apprehension function, so it rolls it up in the grass, introduces it into the mouth and with the use of the lower incisor teeth makes the cut, crushing it slightly. This procedure is repeated several times until a mass of approximately 100 g is obtained, which is mixed with saliva, forming a bolus that is ingested. Cow saliva is formed in large quantities and is produced by various glands, secreting different substances to facilitate wetting of the grass and its chewing, but also to control the pH of the bolus during the digestive process.
- Esophagus: the bolus, which is already a slightly chewed mixture mixed with saliva, passes through the pharynx until it reaches to the esophagus, from where it is transported to the stomach.
- Stomach: it is a sac-shaped structure that begins with the end of the esophagus and ends in the duodenum. It is made up of several parts and, particularly, it is home to different specialized microorganisms that are essential for the digestive process of cows.
And if you're also wondering how cows produce milk, you can check out this other article on our site on How do cows produce milk?
Do cows have 4 stomachs?
The saying that cows have 4 stomachs has become popular, but it is not entirely true. Cows have a single stomach, divided into four structures: rumen, reticulum, omasum and abomasum, in each of which a phase of the digestive process takes place. Thanks to this digestive system, they are physiologically and anatomically capable of optimally processing, digesting and absorbing nutrients, thus ensuring that these animals are properly fed.
However, not only is the stomach of the cow divided into several parts, but it is common in the stomach of ruminants. In fact, ruminants are also known as polygastric animals, due to the division of their stomach. In this sense, these animals have a complex digestive structure that is divided into several parts and, in the case of cows, specifically into four. But what are those 4 parts of the stomach of cows? Let's see them next.
Parts of a cow's stomach
The stomach of these animals is made up of four compartments or chambers, which gives complexity to this organic system, which is why it is usually said that cows have four stomachs.
The parts of a cow's stomach are:
- Rumen: here is the population of microorganisms that initiates the fermentation of the bolus in order to transform it. This is the largest compartment of all, and can have a capacity of up to 200 liters. Certain fermentation products are already absorbed by the rumen walls and pass into the bloodstream. Other compounds that are not fermented, are transformed into proteins used by the animal. The time that the food remains in this area can vary, about 12 hours for the more liquid fraction, and between 20 to 48 hours for the fibrous portion.
- Reticle: this chamber has the function of containing the food, transporting what has been digested and is more liquid until it curdles or abomasum of the cow, while the larger remains are taken to the rumen to be regurgitated from this chamber back to the mouth and thus rumination takes place.
- Omasum or booklet: this compartment is characterized by being made up of various folds, which is why it is also known as a booklet. The function of the cow's omasum is to absorb excess water so that the food passes to the next structure as concentrated as possible and the enzymes involved in digestion have not been diluted.
- Abomasum or curdling: also called curdling of the cow, it is the stomach itself of the animal. The acidity of this area is high, so here all the microorganisms that had been processing the food are digested, also stopping the fermentation. Hydrochloric acid and pepsin are produced, favoring the processing of proteins that have arrived in the area, causing a chemical digestion of food.
Other digestive structures of cows
Other digestive structures of these animals are:
- Small intestine: The products of digestion that take place in the four stomach compartments of the cow are absorbed in the small intestine.
- Large intestine: in the large intestine, the components not yet digested will be processed by a less prolific population of microorganisms that will perform a new fermentation.
- Cecum: Undigested food mass transits through the cecum.
- Colon: the colon of the cow is the place where the absorption of water and minerals occurs, to subsequently form the fecal matter that it will be eliminated through the rectal canal.
