It’s trendy to be vegetarian or vegan. For some people, this goes as far as putting their cats or dogs on a meat-free diet. But is this a good idea?
If I’m hearing you right, it makes a big difference to a dog if it eats a vegetarian diet as opposed to a vegan one. Absolutely. A vegetarian diet allows for animal products such as egg, milk, wool fat or cheese. These products in turn contain animal protein, which has the perfect composition of nutrients for a dog. In a vegan diet, animal proteins are strictly off-limits.
Let’s draw an interim conclusion at this point: putting my dog on a meat-free diet is... ...possible. The question is whether it’s also species-appropriate, especially since dogs are carnivorous by nature.
But it doesn’t just have to be meat alone, right? I mean, dried food usually has grain added to it. That’s right, it doesn’t have to be just meat. Small amounts of carbohydrates don’t pose any problems. However, cats get most of their energy from protein and fat, with only a very small proportion coming from carbohydrates.
Organisations such as PETA have been propagating for some years that it’s absolutely species appropriate for our four-legged friends to be put on a vegan diet. What do you say to that? At least for cats, vegan diets aren’t species appropriate and constitute an animal welfare concern. Although a healthy dog can be put on a vegan diet, it still begs the question of whether this is species appropriate.
Claudia Nett-Mettler is a practising veterinarian. One of her specialist qualifications is in nutrition for dogs and cats. She is President of the Swiss Association for Small Animal Medicine SVK. The SVK published a position paper on vegetarian/vegan diets for dogs and cats in December 2020.
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I have cats but I haven’t yet addressed the question of whether I should be rearing my furry friends as veggies. They get their dry and wet food with meat. And between meals, they hunt mice and birds outside, generally leaving very little left over besides the mess I have the pleasure of cleaning up. These days, increasing numbers of pet owners who’re vegan or vegetarian are feeling the pangs of a guilty conscience because their dog or cat eats meat. With them in mind, I got some advice from a vet – Dr Claudia Nett-Mettler.
Galaxus: Dr Nett, we’re hearing more and more often about people who’re considering putting their four-legged friends on a vegetarian or even vegan diet. Generally speaking, what’s your position on this? Claudia Nett: If pet owners want to be vegetarian or vegan, that’s their personal choice. However, if you’ve got a pet – and especially if it’s a carnivore – it should be fed in a way that’s appropriate to its species. At the end of the day, carnivores are meat eaters. Feeding them plant-based food against their nature is ethically questionable, if not a matter for animal welfare.
Let’s take a more nuanced approach to dogs: what might a vegan or vegetarian diet be like for them? Is it even possible to feed them that way? It’s possible for dogs to eat a vegetarian diet – at least for healthy, adult ones. Things get a little trickier when it comes to veganism. There, it’s difficult to get the right mixture of additives such as vitamins and minerals because they’re either not at all present in plant-based foods, or aren’t present in sufficient amounts.
Just because it’s possible to do something doesn’t mean you should. Does it actually make sense to put your dog on a meat-free diet? Biologically speaking, dogs are still carnivores and not omnivores like us humans. However, during their evolution from wolves to dogs, their digestive systems adapted. A dog’s digestive tract can handle plant proteins and break down carbohydrates pretty well too. That said, a dog’s teeth are still arranged in the manner of a carnivore’s, with canines. Its digestive tract is also very short, which is typical of a meat eater. After all, animal proteins are easier to digest than plant proteins. I can, however, put a fully grown, healthy dog on a vegan diet as long as I pay special attention to the food. The most suitable plant protein source for dogs is soy as it’s the closest to animal protein in terms of amino acids. Puppies and pregnant, lactating or sick dogs should never be reared as vegan. Their amino acid needs can’t be properly met with a purely plant-based diet.
What are the possible risks for dogs on a meat-free diet? Giving an animal meals without the right quantity of minerals or vitamins can cause deficiencies. Protein deficiency manifests as muscle loss and a thinning, dull coat. A calcium deficiency can cause pathological bone fractures or crooked legs. A zinc deficiency is particularly evident when the skin becomes crusty and the claws go brittle. That’s why getting correctly balanced food is very important. A balance containing enough of all the necessary substances, that’s of good quality and is appropriate to the age of the dog.
Meat primarily contains protein, the building blocks of which are amino acids. Certain amino acids are essential for dogs and need to be absorbed with food in sufficient quantities. In a vegan diet, these amino acids come from plant foods such as soy, peas or other legumes. The composition of plant proteins differs from animal protein, so there may be an insufficient or unbalanced intake of certain amino acids. Dogs need a relatively high amount of protein, which is difficult to cover with plant proteins alone. They do need to like and eat up the meal, after all. Dogs also need a lot of calcium, with bone being an important source of this mineral. In a vegan diet, calcium has to come from other sources, most of which are synthetic. The same applies to certain vitamins and fatty acids.
Speaking of carnivores, biologically, cats fall into this category too. What would a vegetarian/vegan diet be like for them? It’s considerably more difficult for a cat to eat a meat-free diet than it is for a dog. Unlike dogs, cats never adapted to plant proteins or carbohydrates over the course of evolution. Cats are dependent on certain nutrients that are only found in meat. These are essential amino acids such as taurine, vitamin A and D, but also essential fatty acids. For that reason, putting a cat on a meat-free diet would be ill-advised.
What happens when a cat doesn’t get meat? Giving a cat unbalanced, vegan or vegetarian meals can lead to deficiencies. For example, it’s well known that a taurine deficiency can cause heart failure. You can see that cats are carnivores from their teeth. Unlike humans or herbivores, they’re totally unable to break down plant-based food and utilise it sufficiently. Because of this, to feed cats in a way that’s appropriate to their species, you have to give them meat.
In Germany, putting your cat on a meat-free diet is against animal protection laws. What’s the situation in Switzerland? The Swiss Animal Protection Act stipulates in Article 1 that the dignity and welfare of the animal must be protected. Under welfare, the first point mentioned is that animals have to be fed and cared for in a way that ensures their bodily functions and behaviour aren’t disturbed. Nor should they be pushed too hard to adapt. In this sentence, it’s clear that making a cat eat vegan food is an animal welfare concern. That means anyone feeding a carnivore a vegan diet is also disregarding the Swiss Animal Welfare Act.
Now there are people who, for a variety of reasons, have a problem with feeding their pets meat. What do you recommend they do? The best thing would be for these people not to keep a carnivore as a pet and to go for a rabbit or guinea pig instead. Jokes aside, anyone who doesn’t want to feed their pets meat from mammals or fish can consider insect protein. Today, there are several complete feeds for both dogs and cats that contain insect protein such as mealworms or fly larvae. Insect protein has a high biological value and using it as feed is reasonably species appropriate.
