Despite earlier issues, I've stuck with Marc Bekoff's Animals Matter, and I'm glad I did: the book has become clearer and more specific, and still covers issues I'm interested in. Bekoff also provides some details to support my earlier argument about environmentalism and vegetarianism:
"it takes eight or nine cattle a year to provide meat for one average meat eater. Each cow needs one acre of green plants, corn, or soybeans a year for its feed. Thus, it takes about nine acres of farmland a year to produce the meat that one person eats.
By comparison, a person who does not eat meat can be supported by only half an acre necessary to grow plant food for a year. Twenty vegetarians could live for a year on the amount of grains needed to provide meat for just one meat eater!"
Bekoff goes on to say that "It takes about 16 pounds of grain to make a pound of beef," and notes that a reduction in meat consumption could allow for more grain to be used to feed starving people in the world.