I may be a vegetarian, but I know that I am an omnivore, and I know that eating animal products is a necessity unless you plan on supplementing. But I for one, am skeptical of the notion that a Dog or Cat, two biologically carnivorous animals, can have a balanced diet consisting entirely of plant-based foods.
For one, their intestines are shorter, which means that less time is spent sending the food from the mouth to the butt. This helps them when eating meat, because if meat stays too long in your intestines, it literally starts to rot inside your body. Herbavores have longer intestines to help digest plants better. The intestines of a dog or cat is rather short, and thus would not be all the helpful in the digestion of plant matter.
The main issue with Vegetarian or Vegan diets for your dogs is that it is REALLY hard to do unless you plan their diet really carefully. And for cats it is outright impossible. When talking about plant-based diets in cats and dogs, ScientificAmerican wrote:
Veterinarian Marla McGeorge, a cat specialist at Portland, Oregon’s Best Friends Veterinary Medical Center, argues that the problem with forcing your cat to be vegetarian or vegan is that such diets fail to provide the amino acids needed for proper feline health and are too high in carbohydrates that felines have not evolved to be able to process. As to those powder-based supplements intended to bridge the nutritional gap, McGeorge says that such formulations may not be as easily absorbed by cats’ bodies as the real thing.
Cats are what you call Obligate Carnivores, like the Venus Flytrap, which REQUIRE the consumption of animal meat in order to survive. These animals can consume a small amount of plant products, but their digestive system lacks the ability to properly digest it. They also need certain vitamins not available in plant sources, for instance, cats need D3 from animal sources, not D2 which comes from plants. WebMD has this to say:
Lew Olson, PhD, author of Raw and Natural Nutrition for Dogs, makes this analogy: “Trying to feed a cat a vegan diet would be like me feeding my horses meat. You’re taking a whole species of animal and trying to force it to eat something that it isn’t designed to handle.”
“For cats, it’s really inappropriate. It goes against their physiology and isn’t something I would recommend at all,” says Cailin Heinze, VMD, a board-certified veterinary nutritionist and assistant professor of nutrition at Tufts Cummings School of Veterinary Medicine.
“For dogs, certainly vegetarian and vegan diets can be done, but they need to be done very, very carefully. There is a lot of room for error, and these diets probably are not as appropriate as diets that contain at least some animal protein,” Heinze says.
…““We did see a case of a cat that almost died as a result of taurine deficiency,” says Jennifer Larsen, DVM, PhD, board-certified veterinary nutritionist and assistant professor of clinical nutrition at the University of California, Davis veterinary school. “The owners were feeding a vegan cat kibble, so a commercially available vegan diet, and they were mixing that diet with cooked chicken breast, for some reason, but it was not enough taurine for the cat, obviously, and it resulted in a near-death experience for this animal.””
Dogs CAN technically be vegetarian however, you just have to be VERY areful in planning their diets. It is really easy to cause your dog harm by messing up their diet. Vitamin/mineral deficiencies can be common in animals who use even commercially available animal foods.
The benefits of a vegetarian diet on the health of the dog is up for debate, however, as there is not enough science to show that this is more beneficial than regular dogfood in any way. When it comes to pets, it is better to follow the advice of animal experts and Veterinarians over vegetarians and vegans any day of the week.