Darkthorn’s Blog

My Journey Through a Ruminant’s Digestive System

I was an organically grown cotton seed which escaped being crushed by the mill (how I escaped… that is another story). As a young one, I was separated from my beloved mother and put into a feed mix. Being a smart seed, I could identify chaff, cotton seed meal, molasses and oats in my surrounds. As part of this mix I was sold to a farmer, who fed me to his herd of beef cattle to fatten them for the table.

The feed was poured into a trough and a cow licked me up and chewed me briefly in her mouth. I was mixed with saliva and incorporated into a bolus. I caught a flash of pearly whites before being swallowed. Peristalsis pushed me down the oesophagus, by my counts nearly a metre long, to the rumen, a huge vat inhabited by an anaerobic bacteria and protozoa which began to digest my faithful companions, the chaff fibers. I saw other victims of the cow’s herbaceous appetite: chicken feathers - looking very bedraggled -, bone meal, fish meal and soybean meal.

The cow must have had a drink then, because litres and litres of water poured in on top of us. I heard from the grapevine, that cows drink up to 100 litres of water per day. Right at that moment it felt like 400 litres. After stewing for a little while we were regurgitated up to the mouth. Because we were a big mass of material passing from the largest compartment - the rumen - into the smallest compartment - the reticulum - we stimulated regurgitation.

The massive molars of the cow’s mouth chewed us as “cud”. This time I observed 32 teeth, 8 in the front of the lower jaw and 12 each at the back of the upper and lower jaws. I was re-swallowed into the rumen and reticulum. In the rumen the resident 500′000 billion bacteria formed essential amino acids from nitrogen and synthesized the B-vitamins the cow needed. The micro-organisms’ waste products, being volatile fatty acids, were absorbed by the rumen walls, which had villi to maximize the surface area available for absorption. I appreciated but could not share the tender symbiotic relationship between the micro-organisms and their cow. Instead I narrowly escaped having my shell crushed by their rumination!

I saw that the reticulum had tiny pockets in its walls, looking like the honey comb which was stored next to my bag on the store shelf. On the floor of the reticulum I noticed a large fencing nail, the missing key to the shed door - she was obviously a house cow - and a granite stone. I hoped that these items would not puncture the reticulum wall. This would be very dangerous for her because she could get peritonitis or even an injury to the nearby heart or diaphragm.

This time I moved on to explore the omasum where I’d say about 65% of the water was absorbed into the cow’s body, together with electrolytes such as potassium and sodium and the remaining fatty acids. The atmosphere was distinctly drier. The walls, floor and ceiling of the omasum looked like the pages of the receipt book I had seen in the store when I was purchased.

I entered the true stomach, the abomasum. I wasn’t sure why it was called the true stomach, as it looked similar to the omasum I had already passed through. But then the walls and duct openings of the abomasum started to spray in digestive juices which included enzymes and hydrochloric acid and I was churned around. The protein and starch of my deceased friends, the crushed cotton seeds, were digested there by enzymes such as pepsin. The micro-organisms that travelled with me from the rumen certainly could not survive in the pH of 2.5 and were given a rumbling requiem before being broken down into peptides. The acid was trying to get through my defensive shell but before it could I was sent to the small intestine.

After passing through these four chambers of the stomach I entered into the small intestine and was once again pushed by peristalsis and was acted on by digestive juices secreted by the pancreas, liver and intestinal wall. All that was left of my companions, was starch, turned into glucose, and complex fats, turned into fatty acids. The pH level rose to 7 or 8 and my shell was saved from almost certain destruction. The small intestine I would estimate to be 40 metres long, in the lower part of which absorption occurred. It was as though the intestinal wall reached out with fingers to draw in the nutrients.

I met some interesting bacteria living in the large intestine whose work it was to digest any remaining foodstuffs. Further absorption also occurred here. While I was passing through the colon I ruminated for quite some time about my experience before I realized that my tough shell had kept me safe through all of the chemical and physical processes of a very rough ride. I survived and passed out as part of a cow pat.

“Plop!”

My journey had exhausted me, but not so much as to prevent my putting down roots and growing into a fine cotton plant with many seeds of my own. I live to this day in quiet corner of a farmer’s pasture.

I wrote this for yaer 11 biology. It was actually quite fun.