@Thomas,
It doesn't occur to you that those who produced the book have a motive for making assertions which they cannot necessarily substantiate?
This entire discussion is so narrowly focused as to descend into the absurd. If one is concerned about cruelty to animals, by all means outlaw veal (on the same principle as Joe says cannibalism should be outlawed, even when there are volunteers, outlaw veal, even if people claim they can raise calves for slaughter without cruelty, outlaw foie gras. But what about the cruelty which is part and parcel of the economic inequalities of the world? What about population issues? Is it not utilitarian for people in what is still called the third world to have large families, and will they not continue to do so unless their economic situations improve to the point at which it is no longer necessary?
If we don't have sufficient arable land to produce feed for feed lot animals, how is that we have sufficient arable land for the huge cut flowers industry, in which Holland and Poland are major players? Is it not just as environmentally irresponsible to burn fossil fuels and dump CO2 into the atmosphere to ship their cut flowers all over Europe and to North America as is any other wanton use of fossil fuels? Is it not criminal that good arable land is used to produce opium poppies and coca leaves the end purpose of which is to exploit the misery of drug addicts, and in the hopes of the producers, to create new drug addicts? Would not a serious international effort to eradicate the sources of heroine and cocaine, and to put that arable land to good use producing scarce grains be as effective an answer to questions about food production as anything else we could do, given the undoubted tragedies of drug addicts?
Is it not a squandering of the production of arable land to use it to produce ethanol to supplement or replace fossil fuels? Does that not only address the issue of peak oil, and not the issue of the production of greenhouse gases?
There are so many issues which are all tied together with regard to food production and consumption which are not touched upon at all in a discussion of whether or not it is "right" to eat meat.