It's a circular argument, of course: the practice (eating meat) comes before the rationalisastion.
This seems to me to be its tenets:
1. Animals are raised to be eaten
2. It is good, and right, to eat animals.
3. It is wrong to not eat animals who have been raised to be eaten.
Of course, the argument would require agreement on its premises (1,2). The person you quoted, doesn't even acknowledge these premises, he/she just assumes them to be shared: the position qouted isn't anything more than a conclusion, 3, it has no building blocks. If we accept this, we also have the problem of roadkill, or animals dying natural deaths, etc, of animals discarded from labs, of cats and dogs (why not eat fido?).
Really, the argument (as stated) is as weak as this:
1. I like breaking windows, glass is designed to break down
2. I think it is right to break windows
3. If a window is there, it is right for me to break it.
You might kind of allow me momentarily to hold 3, but you would want to debate its conditions (1,2) and probably disagree with them. The farmer doesn't allow any debate of his assumptions because he irons them out if the argument.