Cattle eat chiefly grass. We shall see how the grass is used, how it is digested.
• Let us watch a cow feeding. When a cow feeds, it takes a little grass with its tongue. It grips the grass between the upper jaw and the teeth of the lower jaw. It jerks its head to pull off the grass.
• Let us look at a cow's mouth. There are two jaws and a tongue. The upper jaw has no front teeth. The lower jaw has eight front teeth. The older the animal is, the more the teeth are worn. You can tell the age of a cow by looking at its front teeth.
Toward the back of the mouth you can see large teeth. With these the cow chews the grass. They are called molars.
When the cow has bitten off the grass, it does not chew the grass at once with its teeth; it swallows it. The grass goes into the first stomach (or rumen).
A cow can eat a lot of grass; there is room for up to 15 kilogrammes of grass in its first stomach, depending on the size of the breed.
But a cow needs a lot of time to feed, to fill up its first stomach. So you must give a cow, and especially working oxen, at least 8 hours a day to feed off pasture.
When a cow has finished filling its first stomach, it often lies down.
But it goes on moving its jaws. It is ruminating.
The cow brings up a little grass from its first stomach into its mouth.
It chews this grass for a long time with its molars.
When the grass is well chewed and broken down, the cow swallows it again.
But this time the grass does not go into the first stomach, but into the second one.
A cow needs several hours to ruminate.
• A cow can ruminate well when it is quiet, and above all when it is Iying down.
If you make a shelter, the cow will be protected from rain, wind and sun; it will be quiet; it will rest; it can ruminate well.
• The cow ruminates because its digestive system is made to digest and transform grass. The digestive system consists of the mouth which takes in the grass, of the first stomach which stores it, of the molars which chew it, and of the other parts of the stomach and intestine which digest it. This intestine is very long, more than 20 metres.
• Animals that ruminate are called ruminants.
Goats, covvs, sheep and camels are ruminants.
Young calves do not ruminate, because their first stomach is not yet developed. So they must be given different food.