I hate to do this, but the amount of uneducated, illogical, and plain wrong comments in this thread is gob-smacking. It's like none of you ever engaged your brains or did any modicum of research before typing your nonsense and providing your incorrect opinions as accurate or relevant.
Yes, billions of animals will cease to exist over a few generations of decreasing breeding rates as the industry came to a close. But these billions of animals are a man-made phenomenon and wouldn't ever have existed in the natural world without the intervention of intense breeding by humans. Billions of animals will cease to be bred each year, thus saving them from a life destined for slaughter. Not forgetting that almost every example of animal we farm for food is an echo of a distant relative, bred far beyond its ability to survive in the wild. They are selectively bred over thousands of years just as our dogs and cats were. Yet I don't see anybody arguing to put all the dashhounds back into the plains of Africa or the freezing Artic circle where they 'came from'.
Yes, no matter what you eat, other organisms will likely have suffered at the expense of the food on your plate. But accidentally killing a variety of insects and small mammals as part of the process isn't a justification for actively slaughtering billions of animals each year. Countless more insects and small mammals (to name a few) are accidentally killed throughout the entire agricultural industry that exists to provide animals their feed. We could but both out simultaneously.
There is so much disinformation on subjects like this it's painful, and as a society we're engrained to believe what wider society, corporations and government lobbyists tell us (meat is great...because it makes people lots of money).