Cows have WHAT? - Another Dairy Post

I remember way back in elementary school, being told that cows have four stomachs. I was confused. Why on earth would a cow need four stomachs? I remember picturing a cow with 4 large chambers located in series from the mouth to the rest of the digestive tract. We were taught nothing more on the subject and left to believe that cows are so huge because they have four giant stomachs inside that body of theirs.

I couldn't have been more wrong.

The stomach is really more of a storage chamber. Ours doesn't actually digest the food fully (another thing we were led to believe as young children... probably because it's easier that way), but it starts the digestion process. A cow does have four compartments, but not necessarily four stomachs. These compartments are vital for the animal to be able to live on grasses and other plants... and for milk production. They are, in order, the rumen, reticulum, omasum, and abomasum.

Rumen: The rumen is the largest of the four compartments. This is where all the food goes to be stored after the animal has first ingested it. At University they had an animal with a hole in it's side where you could actually stick your hand into the rumen and see it's contents. It didn't smell very good, let me tell you. That is because there are some bacteria in here starting to break down some of the grasses. Basically, it looks like very wet, somewhat ground up grass. Kind of like silage!

Reticulum: Once the cow has eaten it's fill, it will chew it's cud... most of it's life is actually spent chewing cud. The cud comes from the rumen and is mixed with more saliva and enzymes in the mouth as it is chewed into smaller pieces. It then goes into the reticulum, where it is further broken down by bacteria.

Omasum: The food moves from the reticulum into the omasum, and it is here that most of the water is removed and 'recycled'. More nutrients are absorbed and enzymes are added as well. This stomach is also the first one really used by the calves. Their esophagus is different, allowing milk to go directly to the omasum.

Abomasum: This is considered the 'true' stomach, and works much the same as ours does. Acids are added here, and the digestion process is now very similar to ours.

That is a very basic overview of the 'stomachs' of a cow. It is extremely important to producers that we make sure we give the animals a good balance of fiber and energy in their feed for milk production... otherwise we may have problems. If we don't give them enough fiber, the acidity of the rumen will increase and many of the bacteria will die, causing a sick cow that doesn't digest it's food properly... and therefore not very much butterfat in our milk (which is important... that's what we're paid for). If we don't add enough energy to the feed, the cow won't produce as much milk either because she's using all the energy in the food for her own basic processes. She'll still make milk, just not as much. She will also tend to lose fat off her back at a quicker rate than that which is healthy, and we can have other problems associated with that. Yeah... feed is important in the life of a dairy farmer... not only for the health of the cow but the milk (aka the money) coming out.

Anyway, I hope you enjoyed your little dairy biology lesson for the day, haha.