Both sheep and goats are ruminants, along with cows and llamas. The general health of all these animals is, by and large, dependent upon their digestive tract. This means they have a complex stomach which is divided into four compartments: the rumen, the reticulum, the omasum and the abomasum. Non-ruminants, such as pigs, horses and man, have a single stomach, equivalent to the abomasum.
The first ruminant stomach is the rumen. Here, ingested food is soaked by stomach acids and subjected to digestion by microorganisms before passing through to the the next stomach. It is from here that food not thoroughly masticated can be regurgitated to be rechewed. This is often called “chewing cud”. Cows do this very often as they are inefficient grazers, but goats do it less often as their lips are capable of selecting the very tenderest plant tips and the back teeth are jaggedly sharp for maximum mastication. The rumen is a large organ and it occupies most of the left half of the abdominal cavity. Animals with rumen problems often look lopsided to the left due to bloating of the rumen. The rumen is normally filled with coarse fibrous materials.
The second stomach is the reticulum. It is characterized by a honeycombed appearance on the inside. These many ridges present a large surface area through which to absorb ingested nutrients. It lies next to the heart. Occasionally, especially in cattle, ingested wire can puncture the nearby heart causing reticulum pericarditis, or “hardware disease”. Goats, of course, would not be inclined to ingest a large piece of wire so this condition is almost unknown.
The third stomach, the omasum, is oval in shape and lies primarily on the right side opposite the 9th and 10th ribs, although it has no contact with the abdominal wall. It is normally filled with fluid to a capacity of 300ml, or about 10 ounces. The abomasum, or true stomach is the glandular portion of the ruminant digestive tract. It corresponds to the glandular regions of the simple stomach of non-ruminants. The rumen, reticulum and omasum are the primary organs of the digestive system, being the main sites for for digestion and absorption of water, electrolytes and volatile fatty acids. The function of these stomachs is closely interrelated and problems with one usually involves the others.