Ruminant Digestive Processes
Ruminant's stomachs are composed of :
The Rumen is where the magic happens. It is at the left side of the abdomen of the animal. It is lined with Papillae, which will be important shortly. Mostly it is just good to know that by way of comparison, Papillae are the things that line our small intestine, and absorb the nutrients that get absorbed from what we eat.
The Rumen is a fermentation vat for primarily anaerobic bacteria. Some aerobic, but far and away mostly anaerobic. The Rumen is a dynamic organ that changes in composition based on diet, and is not functional at the birth of the animal.
Rumen breaks down fibrous feed into Acetic Acid, Butyric Acid, and Propionic Acid.
The Rumen does this with Cellulolytic microbes (microbes that, not surprisingly, break down cellulose.)
It also utilizes various other microorganisms to assist in turning cellulose and starch to glucose. Once bacterial enzymatic action has converted the polysaccharides to glucose, the glucose goes down what is called the E-M Pathway, which for all practical purposes makes the cow belch, and fart as much as it famously does. This is all in the name of the production of three types of volatile fatty acids: Pyruvic acid first. Pyruvic acid is generated directly from Glucose, and is subsequently the feedstock for two of the other three volatile fatty acids important to the cow and Rumen function: Propionic acid, Acetic acid, and Butyric Acid.
Of these three, Acetic acid is the most flexible and important due to the fact that it can further be turned to Butyric acid. Also they are the most important components of the VFA's in the production of the substance that we are trying to arrive at here: Butterfat, or in the typical parlance of Hicks like me: butter.
There is all kinds of interesting stuff I could tell you here that I have learned about how this entire process works in healthy cows and is completely screwed up, even though it is essential to the health of the cow, when you feed the cow grain instead of cellulosic feedstuffs: grain instead of grass is bad for the Rumen and terrible for the cow.
So, that's my not terribly thoroughly detailed explanation of how grass gets to butter in a cow. After the rumen allows the cow to ferment the grass into the Volatile Fatty Acids, listed above, those fatty acids are absorbed by the cow, and utilized as it's main energy source (through the same pathways that cream, butter and beef fat in a steak, or in your old fashioned french fries, would be used for energy by you.) I love that. The left over VFA's become adipose tissue on the cow (love handles) or more likely, go into it's milk production, in tiny little droplets that float to the top as cream in unhomogenized milk. Separate the cream, shake or otherwise agitate that cream and voila, the grasses cartenoid (yellowish pigments in grass pretty much the same as the pigments in fall leaves that might make them yellow) pigments show up in globules of fat that the world over covets as butter.
So to quickly review:
Grass grows beneath the sun, taking carbon dioxide and water to make polysaccharides (through photosynthesis) that constitute the vast majority of its structure. These polysaccharides are shorn from the ground by the specialized teeth of ruminants, like cows. The grass is chewed and taken into the Rumen of the ruminant. There, within the Rumen, the grass undergoes fermentation by anaerobic bacteria that disassemble the grasses polysaccharides, turning them to sucrose. This moment, grass to sucrose, is probably the magic moment which we haven't been able to replicate efficiently. But to continue, the sucrose is taken down various microbial pathways and turned into Propionic, Acetic and Butyric Acids, Volatile Fatty Acids, which are then taken up by the cows rumen's papillae. At this point what happens to them is irrelevant, for, they are in the realm of all vertebrates; part of a pathology hardly specific to a ruminant. Too bad, they're creative guys aren't they.
So, say a prayer to the Rumen. Trust me, in many ways, even a short review of the literature devoted to what makes you and me different from people starving on TV will have a goodly number of volumes showing how a person devoted to ANYTHING other than merely feeding himself is a person dependent on the Rumen (and anaerobes) of a Ruminant. No matter how much I finally learn by the end of my life, it will never be enough. In an endless virtual cycle, the ruminant made what I am doing possible. And who knows, perhaps my friends and I will do our part to see to it that one day the ruminant is respected in it's preference for that magnificent thing, which I will indicate only in Pete Seeger's incantation:
"God Bless The Grass."