If protein comes from cows and they only eat grass how does the protein get in there?!
Cellulose makes up the cell walls on grass. Cows can digest this (we can't). The amino acids that make up the protein in grass are digested and broken down by the cow and rearranged to form the cow's own protein and thus grow. The grass absorbs nutrients from the ground and makes it's amino acids. This is a very brief and probably not overly scientific explanation but does it help? Consider that beans and pulses also contain lots of protein - they are plants as well.
Every single living organism in the world is made of protein. Even non-living organisms like viruses are made of protein. The idea that there is no protein in plants is an old myth and I've got no idea where it comes from, but I wish it would go away.
So some plant parts have no protein, like some fruits eg apples. But for the most part, if it is fresh and you can eat it it will give you protein. When you eat it, your digestive system breaks the protein down into amino acids which are then reconstructed as human proteins in your cells, just as the proteins in grasses are broken down into amino acids and made into cow proteins in the cells of a cow.
The protien is in the "meat" or muscles of the cows. And actually greens have some prtoen in them as well. So vegitarian can get protien from dark leafy veggies and I imagine cows get protien from the grass.
They are chemical reaction inside cows stomack,like plants giving protin after sucking water and nutrient from earth by roots.
Protein is in their muscle naturally. Vegetarians have protein in their muscles too.
their mother's milk, and then grass(or whatever they're given, as not all cows are allowed to graze).
Protein is in the vast majority of foods, sweetheart.
They have four stomachs, 'nough said.