If you have heard that sheep have four stomachs, you haven’t heard an accurate fact; however, it’s also not too far from the truth. You see, sheep are a ruminant species, which means they have a four-chambered stomach and a distinctive digestive process. Ruminants are mostly distinguished for their “cud-chewing” practices, which involve chewing, regurgitating, re-chewing, and swallowing their food. The term “cud” refers to the food bolus (a large mass or lumped of chewed food) that is created and regurgitated for re-chewing and swallowing. The reason why they are called ruminant species is mostly due to their four-compartment stomach, also called the rumen. The four parts include the rumen, reticulum, omasum, and abomasum. Single-stomach species, like us, are referred to as monogastrics.
The rumen takes up most of the space within the abdominal cavity in a sheep. It serves as a large storage vat for fermenting food, and contains billions of microorganisms and microbes, including protozoa and bacteria. This allows sheep to properly digest their fibrous diet of grass and grain. Initially, food is quickly eaten and swallowed, but then later regurgitated, re-chewed, and re-swallowed. This process is called “rumination” or “cud chewing”, and is very distinctive of ruminant species, including elk, goats, cows, mules, deer, moose, giraffes, and more. Sheep usually ruminate during rest or sleep, and not while eating. Mature sheep will chew their cuds for several hours every day.
Rumination also produces a lot of gas in the stomach as well. Sheep must get rid of this gas through belching. If anything impedes a sheep’s ability to belch and eliminate gas, it can be life threatening. A common condition that results from an obstruction of belching is bloat. Bloat is serious and can be fatal to sheep and other ruminant species. Antacids or sodium bicarbonate (baking soda) can usually manage minor cases of sheep bloat, but more serious conditions require emergency veterinary service.
The remaining parts of the rumen include the reticulum, omasum, and abomasum. The reticulum looks like a honeycomb, and serves as the assistant to the rumen since both parts continually mix food back and forth. The reticulum does not experience a lot of digestive activity. It is made up of several layers, giving it the colloquial term, many piles. The last part of the rumen, the abomasum, is an interesting part because it is basically the actual stomach of the sheep. The abomasum works just as a regular stomach would in a monogastric species, excreting enzymes and acids to break down nutrients and aid in digestion.