The demand for meat would go down, the farmers would breed them less. These domesticated breeds would probably mostly die, and be eaten, until they'd be gradually faded out. This would never happen. But you can play a part in lowering the demand for meat, and in turn, lowering the amount of animals that get slaughtered. Think about at least lessening the amount of meat you eat. The American Heart Association recommends you eat red meat, no more than once every 9 days. Also eat chicken more sparingly, and you will at least help some. I have been vegetarian for a year and a half, and it was the best decision I've ever made, think about all the animals I have saved. Also, please make sure you are not eating fish, they are wild animals. And if you do eat fish, make sure you've checked whether it's sustainable. The fishing industry is depleting the ocean of fish, and guess what, other wild animals (dolphins, whales, sea lions, etc.) depend on these fish. Check out this website: http://www.montereybayaquarium.org/cr/seafoodwatch.aspx, for more info on sustainable fish sources.