I know that you are a reptile tumblr but I was wondering if you knew if it were healthy for dogs to be vegans? I'm just curious because of some vegans that have animals and they make them vegans... is it harmful towards the animal or is it completely safe? thank you :)
It’s an absolutely horrible idea. Dogs cannot be vegans and thrive. They’re not vegetarians and they’re not even really omnivores in the same way we are- while dogs will eat everything we do (and more), feeding them a vegan diet is terrible for their health. A lot of vegans who make this decision will blather on about supplements in the vegan food or about how you can make artificial amino acids or how dogs can survive on it so therefore it’s safe, but dogs can also survive eating Ol’ Roy, the worst dog food in the world. Surviving isn’t the same thing as thriving! A dog’s biological structure means that eating plants and only plants isn’t going to work well in the long run- so let’s look at some of the reasons why dogs need to be fed a diet based in animal protein.
1. The canine digestive tract is not good at digesting plant matter.
Plant matter is really tough to break down! Meat, on the other hand, digests quickly. Carnivores and herbivores have differently structured digestive tracts that work with their diets. Let’s look at a rabbit’s digestive tract and a dog’s.
See how a rabbit has a functional cecum, while the dog’s is just a little snub of a thing? The cecum is an organ that plays a really important role in non-ruminant herbivore digestion. It’s a large pouch where cellulose and tough fibers in plant-based food get broken down. Dogs, like humans, don’t have one that’s functional for digestion.
In addition, herbivores like rabbits have very long, complicated digestive tracts. Their food sits in there and breaks down over a long period of time. An average adult rabbit (with a body of about 40 centimeters long, we’re not talking the giant breeds or the dwarf breeds here) has about three meters of small intestine. In American units, that’s a 15 inch animal with almost 10 feet of intestines. A dog, on the other hand, has a small intestine that’s about two and a half times the length of its body- so for instance, a dog that’s two feet long would have about five feet of small intestine. There’s neither enough time nor space in the canine alimentary canal for dogs to fully extract the nutrients they need to survive.
2. Dog drool doesn’t have amylase.
Amylase an enzyme that converts plant starch and glycogen into simple sugars. Herbivores and omnivores typically have amylase in the saliva, which starts to break down those starches immediately. This means by the time the starches hit the intestine, they’ve already started to convert into something that’s actually useful. Dogs, however, only produce it in the pancreas. There’s no salivary amylase in dogs or any other carnivore. This means that digesting plants and converting their energy into something that’s actually useful is really inefficient for dogs; they can only get something like half of the energy and nutrients they’d get from a comparable amount of meat. It also means that to digest plant material, dogs’ pancreases have to go into overtime to make enough amylase, which can lead to severe pancreatic strain.
3. Dogs can’t digest cellulose.
While the dog pancreas makes amylase, something it doesn’t make is cellulase. Granted, herbivores don’t make it either- in fact, very few animals do. Termites are one of the only animals that make their own cellulase. Herbivore digestive tracts have a reservoir of symbiotic bacteria that produce plenty of cellulase. We’ve actually talked about it- it’s what goes on in the cecum! The bacteria in carnivore ceca, however, is linked to the lymphatic system, not the digestive system.
There’s also the issue of their teeth not being adapted for a plant-based diet or even the way they eat being good at taking in plants- but the same is true for anything that’s not animal carcasses, including kibble and wet dog food. That’s just evidence that defines them as opportunistic carnivores; what makes a vegan diet so bad for dogs is their digestive biology.
There is one exception to this rule, and that is when a vet prescribes a vegan diet for an animal with significant food allergies or other dietary issues. This is not something vets do unless it’s the best course of treatment for the animal.
Veganism isn’t the same thing as being an herbivore. Herbivores don’t have a choice; their bodies aren’t built for eating meat. While they might take in animal protein on occasion (deer, for instance, will eat birds sometimes), their teeth, their digestive systems, and their metabolisms all work together to make eating plants the best way for them to survive. A rabbit’s not a vegan- it’s an herbivore. Only humans can be vegans. To be a vegan is to make a choice; it’s to evaluate your place in the world around you and to renegotiate your relationship with all sorts of things- your own body, the food industry, the people around you, and of course the animals you don’t eat. Responsible vegans understand that humans can thrive on an all-vegetable diet; they know that we evolved to be really, really flexible when it comes to the source of our nutrition. While humans are biologically omnivores, we can make that choice.
A dog can’t, and it’s not humanity’s place to force that on them. There are some pets that thrive on an all-vegetable diet. Rabbits, tortoises, finches, hamsters, snails- but not dogs.
If you’d like more information, this is a fantastic write-up, complete with sources! This is a good, short article written by a vet. This is a blog post that talks about some of the other nutritional deficiencies, particularly involving D3. This is another great writeup with diagrams!