They graze.
The cow eats grass is a correct sentence.
Unless there's bits of plastic on the hat that may block the cow's digestive system on the way down and out, it shouldn't hurt the cow.
No.
Seals and any other big animal eats cow fish.
No, a cow eats grass.
chicken
Rachael the Cow eats Exotic Fish
Humans.
Like when a cow eats a GMO product, then we eat the cow.
It is called rumination, or chewing cud. Also, see the related question below.
Yes, a dog can get cow parasites. If a dog eats cow feces, then it could get cow parasites such as, worms.
Probably not even a cow at all.