Plants:
Well the obvious here is that more plants are consumed by meat eaters as large amounts must be fed to livestock. So being vegetarian saves animals, reduces plant waste and water waste. PETA actually answers this 'question'
"What about plants?"
There is currently no reason to believe that plants experience pain, devoid as they are of central nervous systems, nerve endings, and brains. The main reason that animals have the ability to experience pain is as a form of self-protection. If you touch something that hurts and could possibly injure you, the pain will teach you to leave it alone in the future. Since plants cannot locomote to escape pain and therefore do not have the need to learn to avoid certain things, the ability to feel pain would be superfluous and evolutionarily illogical in plants.
Furthermore, even if plants were able to suffer, it wouldn’t justify causing pain and distress to animals like dogs, cows, rats, or chickens, who we know are capable of suffering a great deal.
Dogs:
Dogs are no more or less deserving of a life free of pain and needless killing. I pass no judgement on a person that eats a dog over a cow, both are senseles deaths.
None.
