The most important factors for difficult dogs are gradual change and persistence. Using these principles, the most stubborn of dogs have been successfully weaned onto healthy vegetarian diets. Vegetarian dog food recipes may be obtained from Peden (1999) and Gillen (2003) and from some of nutritional supplements.
Meatless Meals for Dogs and Cats | PETA
Cats are often more finicky than dogs, and their nutritional requirements are more complicated. Cats need a considerable amount of vitamin A, which they cannot biosynthesize from carotene, as dogs and humans do. Insufficient amounts may cause loss of hearing as well as problems with skin, bones, and intestinal and reproductive systems. Cats also need taurine. A feline lacking taurine can lose eyesight and could develop cardiomyopathy. Commercial pet-food companies often add taurine obtained from mollusks. James Peden found vegetarian sources of both taurine and vitamin A, plus arachidonic acid, another essential feline nutrient. He then developed veterinarian-approved supplements Vegecat™ and Vegekit™ to add to his recipes.
Vegan Dogs (and homemade dog food!) - Happy Herbivore
Making vegetarian food for dogs is easy because dogs, like people, are omnivorous and usually hearty eaters. Recipes for vegetarian and vegan dogs are available along with the Vegedog™ supplement from James Peden’s company, Harbingers of a New Age. It is important to follow directions carefully. If you make any changes in ingredients, make sure that you do not change the nutritional balance of the recipe. If a dog receives too little protein, calcium, or vitamin D, his or her health could be jeopardized.
Water is in the rice they eat and the beans I cook for them-- vs