What makes cows drink so much water?
Instinct, sir--instinct.

Something whispers to 'em that if they don't sluice in a little water that caseine'd make 'em giddy and eat 'em up.
Now, what's the odds whether I put in the water or the cow does?
She's only a poor brute beast, and might often drink too little; but when I go at it, I bring the mighty human intellect to bear on the subject; I am guided by reason, and I can water that milk so's it'll have the greatest possible effect.
"Now, there's chalk.

I know some people have an idea that it's wrong to fix up your milk with chalk.

But that's only mere blind bigotry.
What is chalk?
A substance provided by beneficent nature for healing the ills of the human body.

A cow don't eat chalk because it's not needed by her.