Subject: How are there enough cows to supply the millions of restaurants their beef?

Since there are millions of fast food restaurants (McDonald's, Burger 
Kings, Wendy's, etc) around the world, how are there enough cows to 
provide the beef for burgers to these fast food restaurants and to all 
other restaurants that serve beef?  At what rate must cows be killed to 
supply one days worth of beef? Is there a cow population?  

Re: How are there enough cows to supply the millions of restaurants their beef?