Why Goats Always Carry the Kings-Hood and a Bible

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Podcast: Why Goats Always Carry the Kings-Hood and a Bible - The Goat Digestive System
Length: 7 min 29 seconds
Written and read by the author

Our genes represent building plans or recipes for protein. The genes of multicellular life’s directly use 20 different amino acids in these protein plans. However, our bodies cannot make all of these amino acids. Those that we cannot manufacture are called essential amino acids because we must include them in our diet. For humans, there are nine essential amino acids, dogs, 10, and cats, 11. For goats? Zero, zip. They make them all through the incredible power of their ruminant four-chambered stomach.

All ruminants, such as sheep, cattle, and giraffes have this ability, and it is nothing short of amazing. Let’s review how this works as it gives us a key into what we need and don’t need to feed goats to stay healthy.

When a goat browses and eats leaves, the mostly unchewed plant material is swallowed and taken to the first and largest chamber known as the rumen. An antiquated term for this is “paunch,” although, no matter how much of a paunch you have, you really never have any at all. The rumen functions as a large fermenter and while it doesn’t make beer, it does do something almost as great.

A wide variety and vast number of bacteria and ciliates call the rumen home. Ciliates are single-celled organisms but differ from bacteria as they belong to the phylum of protozoans.  If you count the number of organisms in a single drop of rumen fluid, you will reach a number that is ten times larger than the entire human population of our planet. Two and a half tablespoons would provide enough bacteria and ciliate cells to roughly equal the number of cells in your whole body. All of them work inside the rumen to help the goat convert things like cellulose, the structural carbohydrate of plant cells, into usable sugars. The bacteria help transform, that is ferment, these sugars into necessary nutrients like acetic and butyric acid. The microorganisms also make amino acids from the inorganic nitrogen in plants. They even make Vitamin K and the different B-complex vitamins. Wow, now that is teamwork!

To facilitate this entire process, some mastication or chewing helps break down the plant material so that the microbes can better do their work. Ruminants bring balls of ingesta, called cud, back up from the rumen into their mouth where they slowly grind the plant material up. Then they swallow and bring up more cud for processing. By doing this, goats enhance digestion.

Cud chewing represents a smart survival tactic. Your mom tells you to slow down and chew your food. If you are a goat, your mom tells you the opposite, “Eat fast so we can get back to someplace safe where we can chew our cud in peace.” Want some savory shrubbery leaves in lion territory, no problem, browse fast and then return to the safe cud-chewing territory.

The fermented digesta then moves slowly into the second chamber of the stomach, the reticulum. We call it the reticulum or honeycomb chamber due to the appearance of its lining. If you have ever eaten tripe, you might have tasted reticulum. Don’t you miss the medieval naming system? There the reticulum was called the kings-hood. The reticulum functions to prevent larger particles from progressing to the next chamber until they have been properly broken down.

From the reticulum, ingesta moves to the third chamber, the omasum. To increase the absorptive surface area, this chamber has a series of leaflets, resembling pages in a book. No wonder, they used to call this organ the “bible” or “book of Psalms.” Along with the reticulum and rumen, the omasum may also be used as tripe. These leaflets absorb water, electrolytes, minerals, and volatile fatty acids. When kids, baby goats, nurse, the milk moves directly (via the ruminoreticulo groove) to the omasum to begin absorption. A goat’s rumen doesn’t function until six to eight weeks of age.

Finally, the ingesta then transfers into the abomasum which we call the “true stomach.” We name it this because, like our stomachs, glands there secrete hydrochloric acid and digestive enzymes. Unlike our stomachs, they make some complex enzymes called rennet which we use in the production of most cheeses. Due to the level of acid, this section represents a hard stop for most microorganisms. Like us, until food then reaches the colon the long path through the small intestines remains low in bacteria. Having gone to such lengths in making nutrients available from plant fibers that the rest of us cannot, goats go to great lengths to absorb these nutrients, literally. The length of a goat’s small intestine is roughly 25 times the length of their own body. By contrast, our small intestines only exceed our body length by about 4 times.

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