The short answer is it depends on the size of the cow, if it's lactating, pregnant, the quality of the hay, etc.
(Last answer said that they fed cows grain. Grain is NOT grass, cows are rudiments, grain lowers the PH levels of their stomach, causes bad tasting milk and lackluster health of the cow, generally used as a cheaper alternative, or to fatten a cow, in large scale production. Not recommended)
Because they like it.
Because they like it.
No. Cows are herbivores, meaning that they are strictly plant-eating animals, not omnivores nor carnivores. Cows eat grass, hay and silage and should eat just grass, hay and silage.
This could be for a number of reasons: they are eating too much grain before eating hay, they are sick, or the hay could be molding or tasting bad.
Yes.
Yes. Hay is THE main staple of any cow's diet when not on pasture.
Cow's eat grass so it usually comes out green. However, it also depends on what the cow eat's. But cow's can't eat that much, just pretty much hay and grass just like horses have to eat hay and grass.
Cows do not eat (nor drink) milk. They drink water and eat forages like grass, hay, silage and grains.
Roughages including hay and grass.
They can, but it's not nearly as nutritious as grass or hay.
Grass, hay and sometimes grain.
cows eat grain, grass and hay