What do cows drink?

Yesterday, my friend was was playing a game with me. She asked me to say as fast as possible "cow1..cow2..cow3.. up to cow20". After that she immediately asked me a question "what does a cow drink?" The counting was meant to confuse you so you will say "a cow drinks milk." I was about to say that, when I thought "No, a cow doesn't drink milk". Then I said "water". Then I said "Actually, a cow drinks milk, when it is young."

Then it struck me that there are many people who think cows provide milk for humans to consume them. Very few people actually think about what's the real reason why the cows produce milk. Whatever dozens of propaganda from the milk industry have brain-washed us into thinking that way... "Chickens are raised for eating", "Cows are meant to provide milk"... The animals exist for their very own reasons on earth, no one is meant to be used for anyone else. Cows produce milk not for us, but for their calves.