Beef Cattle

Beef Cattle Information and Resources

Cow Stomach

A Cowboy’s Understanding of the Cow Stomach

Are you like me and not sure you really ever understood the cow stomach while in school or maybe I just plain forgot? About all I remember is that she has four. So I am undertaking a little project to do some research just to see if I can learn a little more about a Cow Stomach or all four.

My first discovery in cow stomach research indicates that a cow is considered a ruminant and ruminants have four stomachs. A ruminant is defined as an herbivorous animal that has multiple chambered stomachs designed to process and digest coarse plant matter. Ruminants regurgitate half digested food and rechew it before swallowing it again and this is known as chewing their cud.

Cow Stomach

Diagram of Cow Stomach

Further research into this Cow Stomach project reveals the Merriam Webster Dictionary definitions as shown below. Now this really clears it up.

  1. Definition of RUMEN: the large first compartment of the stomach of a ruminant in which cellulose is broken down by the action of symbiotic microorganisms.
  2. Definition of RETICULUM: the second compartment of the stomach of a ruminant in which folds of the mucous membrane form hexagonal cells.
  3. Definition of OMASUM: the third chamber of the ruminant stomach that is situated between the reticulum and the abomasum.
  4. Definition of ABOMASUM: the fourth compartment of the ruminant stomach that follows the omasum and has a true digestive function.

Below I detail my definitions of the four parts of a Cow Stomach  as I understand them. Of course it might also be termed what I think they are.

  1. Cow Stomach

    Rumen of Cow Stomach

    Rumen: The rumen is a fermentation vat that catches and holds the roughage (grass, hay, shrubs, etc) in an anaerobic environment for good mixing and processing for further digestion and absorption downstream.

  2. Reticulum: This is the second stomach and it almost goes without saying that as the fermentation breaks down the coarser feedstuff it flows into the reticulum. Cows are well known for “cud chewing”. For what it is worth the text book says that rumination is regurgitation of ingesta from the reticulum, followed by remastication and reswallowing.
  3. Omasum: Textbook says the function of the omasum is rather poorly understood. My take is that as the third reservoir it allows the liquids to pass through quickly and holds back the still bulky material for further processing into a more liquid state.
  4. Abomasum: This is the real stomach and once food or feedstuff gets to this point it is pretty well processed in the same way we humans digest our food.

Now if this Cow Stomach project has your attention well enough that you would like to review a six page technical definition in PDF format Click Here.