Re: what happens if cow is not milked?

Nothing if it was not feeding a calf or producing milk already. But, I 
guess you meant, 'what would happen if you didn't milk a cow that is in 
full production". A dairy cow producing an extra large amount of milk 
could get into some trouble. It's udder would become very distended, and 
enlarged and probably start leaking milk! It may even develop an 
infection and get mastitis which could in turn kill it. 

That's the worst case scenario. More likely, after some days of 
discomfort it would reabsorb the milk and stop producing. 

A cow that is not a high producing dairy cow, would not have any real 
problems. Just be uncomfortable for a few days and then stop producing 
milk.

How do I know?.... I have lots of cows and some lose their calves. No 
problems. 
Cheers Royce