Cattle's Digestive System

For those who don't know cattle have 4 stomachs, the rumen, reticulum, omasum, and the abomasums.  But what is the purpose of cattle having 4 stomachs?  The reason is because of the amount of roughage that cattle consume.  On average cattle will eat 2-2.5% of their body weight in dry matter everyday!  But how about we start our journey through the stomachs, after cattle have ingested their feed it first enters the rumen. 

Our first stop on our journey is the rumen.  The rumen is the largest of the 4 stomachs and contains millions of microorganisms.  These microorganisms live in a symbiotic relationship with the cow getting a warm safe place to live while they are the reason that the cows are able to consume and digest such a large amount of roughage.  In fact 60-80% of the energy required by the cow is absorbed out of the rumen after the microorganisms have broken the matter down into fatty acids. The reason that this much energy can be acquired so quickly is that there are 25 to 50 billion bacteria and 200 to 500 thousand protozoa in every milliliter of rumen fluid.  But have you even seen a cow just standing there chewing? This is because they are regurgitating, or chewing their cud.  This makes it easier to be broken down as when it is first ingested the feed is hardly chewed.  The cud is then again swallowed and goes through the process in the rumen again. 

As we keep rolling along the next stop is the reticulum.  This honeycomb like structure acts as a filter that stops any indigestible materials from passing on into the other stomachs.  The contents of this stomach can include rocks, nails, or other metals that have been ingested.  This stomach is essential in protecting the remaining two stomachs but if wire or other metal punctures the reticulum it becomes the site of hardware disease, which is an infection or irritation to the heart, diaphragm, or lungs.  This why it is important to keep your pastures, pens, and feed free of metal and other debris.  However they do make special magnets that you can give to an animal that consumes metal to help prevent from the animal getting hardware disease.  

Our third stop along the way is the omasum.  This stomach can be described as looking like a book as it has so many layers that they look like pages.  The omasum serves to create a greater amount of surface area for better water extraction. 

The final stop for us on our journey is the abomasums, this is the “true stomach” o a cow.  It is the most similar to the human stomach, it secretes protein and starch digesting enzymes to further digest the feed that wasn't digested in the rumen.

The contents then make their way through the small intestine where nutrients are further absorbed from, until it makes its way into the large intestine and then of course back on the ground again.  But that is the interesting insides of a cow, at least as far as I’m going to get into.

Until next time,

Luke