These components are needed to build and maintain tissue and carry out biological reactions, and the necessary amounts vary somewhat with the dog’s stage of life (puppy, adolescent, adult, pregnancy, senior). A diverse diet doesn’t have to include animal foods; we can be healthy and well on vegetarian or vegan diets, too. We just need to make sure we plan them well so we get enough protein, and make sure we include sources of vitamin B12; something we’ve also evolved …