Digestion
Our bodies employ digestion to disintegrate and absorb nutrients from food, but not all animals have the same capacity for food digestion. Cows, for instance, have a totally different digestive system from ours, which enables them to survive primarily on a diet of grass.
Let's investigate how cows can consume grass. The stomach holds the secret to this skill. The stomach acts as a holding tank where digestion occurs and food starts to be split into specific nutrients after we chew and swallow our food.
Following this, food travels into the small intestine, where it is further broken down and the body absorbs nutrients. Cows also go through this fundamental digestive process, however there are a few more phases.
1. Eating
Because they have less teeth than other animals, eating cows are unusual. Only the lower jaw has teeth in the front of the mouth, known as incisors. The upper incisors are replaced with a firm, leathery pad called the "dental pad" in the mouth.
In contrast to goats and sheep, cattle also have a rather immobile upper lip. A cow uses its tongue to grip a clump of grass before biting it off due to its special oral structure. The top and bottom jaws each include molar teeth, which are teeth in the back of the mouth.Eating Plant materials can occasionally have tough stems, but because cows masticate their meal in a side-to-side motion, the stiff stems are broken down into smaller, easier-to-digest bits.
2. Abdomen
Not only do the letters identify the structures, but they also depict the route that food takes throughout digestion. The dog's stomach resembles ours in many ways. Check out the cow's stomach to see how many more structures there are. Instead of having just one pouch, the cow has four interconnected pouches, each of which serves a different purpose.
A cow chews its grass intake very little at first before swallowing it. This is a defining trait of cow digestion. Cows are referred to as "ruminants" because their stomach's largest pouch, the rumen, is so huge. Think of a large 55-gallon trash can. The rumen of an adult cow is almost the same size! Cows can eat a lot of grass because of their size.
Cows choose a place to lie down to chew their food more thoroughly after filling up on grass. You could be thinking, "But they've already eaten." Although this is the case, cows can intentionally "un-swallow" their food. This process of swallowing, “un-swallowing”, re-chewing, and re-swallowing is called “rumination,” or more commonly, “chewing the cud.” Rumination enables cows to chew grass more completely, which improves digestion.
The reticulum is directly involved in rumination. The
reticulum is made of muscle, and by contracting, it forces food into the cow’s
esophagus which carries the food back to the mouth.
sometimes called the “honeycomb” because of its distinct
honeycomb-like appearance. See Figure 1 for a close-up look.
With a simple stomach, the dog, and even man, cannot digest many plant materials. A cow’s rumen is different because it functions like a large food processor. In fact, millions of tiny organisms (mainly bacteria) naturally live in the rumen and help the cow by breaking down plant parts that cannot be digested otherwise.
These tiny organisms then release nutrients into the rumen. Some nutrients are absorbed right away; others have to travel to the small intestine before being absorbed.
To help the cow’s body capture and
absorb all these nutrients, the inside of the rumen is covered by small
finger-like structures (called papillae).
There is little goodbye between the first two sections of a
cow’s stomach, the reticulum and the rumen, so food and water pass
back and forth easily. The next pouch in the stomach is the omasum . This pouch acts like a giant filter to keep plant particles inside
the rumen while allowing water to pass freely. By keeping grass pieces and
other feed inside the rumen, bacteria have more time to break them down,
providing even more nutrients for the cow.
After the grass pieces and other feed are broken down to a small enough size, they eventually pass through the omasum and enter the abomasum . The prefix “Ab-,” means from, off, or away from. The abomasum, then, is located just beyond the omasum.
You see, the abomasum has the same basic
function as the stomach of the dog, man, or other mammal, which is the
production of acids, buffers, and enzymes to break down food. After passing
through the abomasum, partially digested food enters the small intestine where
digestion continues and nutrients are absorbed.
The Benefits
The rumen efficiently extracts nutrients from food other animals cannot digest. For this reason, cows can eat plant materials (such as seed coats, shells, and stems) that remain after grains are harvested for human feasting.
These remaining materials are sometimes called “by-products.” Feeding
by-products helps farmers and businesses save money by not having to pay to
dispose of these extra materials and make money by selling the by-products as
animal feed.
When oil is extracted from grains (for example, soybean oil from soybean seed and Canola oil from rapeseed), or grains are used to brew alcohol or make fuel-ethanol, plant by-products are made. Although key nutrients (like fat, sugar, and protein) are removed from the plant materials during processing, when used properly, these by-products can be fed to cows.
The complex nature of their four-compartment stomachs and their rumen bacteria
allow cows to eat and thrive on plant by-products that other animals cannot
digest.
The better we understand the cow’s digestive system, the better we are able to formulate diets and manage our herds for the optimal production of the nutritious meat and milk we routinely enjoy.
So, the next time you have a cool glass of milk, a cup of ice cream, or a juicy hamburger, you will know that these products came from cows fed grass, grain, or by-products, and you will know, How Cows Eat Grass.
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