Factory farming and the climate crisis have spoiled some people’s appetite for meat. According to figures from the German Ministry of Food and Agriculture, 14% of Germans followed a vegetarian or vegan diet last year.
When it comes to pets, however, people face a dilemma. How is it justified to provide kilos of meat to dogs and cats that you yourself reject for ethical or other reasons?
In the past, dogs had to make do with leftovers. Today there are foods specially adapted to the needs of pets, some of whose ingredients read like those of a dish for humans: exclusively organic, gluten-free, vegetarian or vegan.
But the vegan diet for dogs has raised reservations among experts and dog lovers.
“Many still see the wolf in the dog, but don’t know that even the wolf did not eat meat exclusively,” says Volker Wilke of the Institute for Animal Nutrition at the University of Veterinary Medicine Hannover.
“During the thousands of years of domestication, he was fed like an omnivore and partly much less meat than today.”
But is plant-only food healthy enough for dogs? A study recently published in the journal Plos One provides some first clues. Researchers in the UK and Australia surveyed more than 2,500 owners about their dogs’ health, the frequency of vet visits and the medications they receive.
Some 54% fed their dogs conventional food, 33% used raw meat and 13% fed their dogs a vegan diet. Dogs fed conventional foods appeared to be the least healthy, the scientists found. Dogs that ate raw meat were slightly healthier than those fed a vegan diet.
However, the differences between these two groups could also be explained by the fact that dogs eating raw meat were on average younger than vegan dogs.
Previous studies had also shown that the risk of malnutrition and ingestion of pathogens is greater with a diet based on raw meat. Taken together, the experts therefore conclude that a balanced vegan diet is the healthiest and least dangerous for dogs.
The study was funded by the organization ProVeg International, which claims to be committed to animal-free diets. Ellen Kienzle, professor of animal nutrition at the Ludwig Maximilians University of Munich, believes the validity of the study is limited.
“It was all a matter of subjective perception. Until a dog shows clear symptoms of illness, owners cannot judge if they are sick,” she says.
“Nobody knows how nutrient availability changes on a vegan diet — and we know it does,” she adds.
So far, there have been few studies on this. For clear evidence, however, studies would be needed on each nutrient. But even drawing blood from a dog for research purposes is considered an experiment requiring permission.
“You have to show that the project is indispensable,” says Kienzle.
As long as people are eating meat, there is, she says, enough slaughter residues such as organs and bones that are only used in animal feed.
“So the vegan diet is a pure matter of sensitivity, a transfer of one’s own attitude towards the dog, and that’s not fair,” she says.
According to previous studies, people who don’t eat meat themselves are more likely to feed their dog a vegan or vegetarian diet.
Researchers at the Volker Wilke Institute have been working on meatless diets for dogs for a long time. “Previous studies indicate that dogs can also receive all necessary nutrients through a plant-based diet using certain additives,” he says.
It is also more difficult to prepare a vegan diet and requires a lot of expertise to ensure that it meets the requirements.
But do dogs that have been fed conventional food really like vegan food? Volker Wilke wanted to test this in a blind study in which 24 students and their dogs participated. A portion fed the dogs dry vegan food from two manufacturers, a control group continued to feed food containing meat.
Over a two-week period, owners had to record whether their dog liked to eat the food and the state of its feces.
“Among the animals with vegan food, there were three dogs that refused it,” says Wilke. “The others, however, were happy to eat it.”
The study is not representative due to the small number of participants.
Wilke says that although interest in vegan nutrition for dogs is growing, it’s still a niche topic. In order to be able to accurately assess its benefits for dogs, long-term studies are needed to examine various objective health parameters such as blood values, effects on fur and animal fitness.
Cats, on the other hand, are a whole other story. Wilke and his Munich colleague Kienzle warn that cats are pure carnivores and cannot be fed a vegan diet. – dpa/Irena Guttel