Because they'd have nothing else to eat. Cows have to eat all the time, no matter what season they're in. Hay is better for their digestive systems than grain is, since hay is simply dried legumes and grass that has been cut and harvested by man. Hay is only fed when cows cannot graze on pasture, especially in the winter and early spring when the grass is too short to be eaten.
Because they like it.
Because they like it.
Four general types: Hay, grass, grain and silage.
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.
Yes.
Grass, hay, grain or silage, depending on the time of year and what kind of farm/ranch they live at and what kind of cows they are.
Yes. Hay is THE main staple of any cow's diet when not on pasture.
No, cows only eat vegetation. Cows are herbivores.
Cows do not eat (nor drink) milk. They drink water and eat forages like grass, hay, silage and grains.
Grass, hay and sometimes grain.
Roughages including hay and grass.
They can, but it's not nearly as nutritious as grass or hay.