can cats eat dog food

You have both a cat and a dog, the bowls are within reach of each other, and inevitably the cat helps itself to the dog's dinner. The good news is that a stolen mouthful of dog food will not harm your cat. The important news is that a cat cannot live on dog food, and the reason is a single crucial nutrient. Here is what you need to know.

Let us separate the one-off from the ongoing, because they are completely different questions. If your cat occasionally sneaks a bite of dog food, or you find yourself out of cat food for a meal and give the cat some of the dog's, that is fine. Dog food is not toxic to cats, and an occasional mouthful or an emergency meal will not do any harm. It is a stopgap, and as a stopgap it is perfectly safe.

why dog food cannot be a cat's diet

The trouble begins if dog food becomes a regular part of what your cat eats, because dog food is formulated for dogs, and dogs and cats have genuinely different nutritional needs. A cat fed dog food long-term will slowly become malnourished, no matter how much of it eats, and the differences are not minor.

The single most important one is taurine. Taurine is an amino acid that cats cannot make enough of themselves and must get from their food, and a lack of it causes serious problems, including heart disease and vision loss, that can become irreversible. Cat food is supplemented with taurine precisely because cats depend on it. Dog food is not, because dogs can make their own, so a cat living on dog food is heading toward a taurine deficiency and the damage that follows.

Taurine is the headline, but not the only issue. Cats are obligate carnivores and need more protein than dogs, and dog food is generally lower in protein than a cat requires. Cats also have specific needs for certain vitamins and fatty acids, including a particular form of vitamin A and a fatty acid called arachidonic acid, that they must get pre-formed from animal sources, and dog food is not built to supply them at the levels a cat needs. Put simply, dog food is a reasonable diet for a dog and an incomplete one for a cat, missing several things a cat's body cannot do without.

keeping the bowls separate

So the rule is easy: dog food is fine as an accident or a one-off, never as a diet. If you have both animals, the practical challenge is stopping the cat raiding the dog's bowl and, just as often, the dog hoovering the cat's. Feed them separately, in different spots or at different times, and consider feeding the cat somewhere the dog cannot reach, up high, since cats are the better climbers. Pick up bowls after meals rather than leaving food down all day, which removes the temptation entirely.

If your cat has been eating a fair amount of dog food for a while, it is worth a word with your vet, who can check the cat is not running short on anything. But for the everyday stolen mouthful, relax. It will not hurt. Just make sure the cat's actual meals are proper, complete cat food, formulated for the small, taurine-dependent carnivore it is, and let the dog keep its own, lesser dinner.

Related reading from my desk: how much should I feed my cat, on getting the real diet right, and can cats eat chicken, a proper treat.

A cat that has been eating dog food regularly should be checked by a vet for nutritional deficiencies. This is general guidance, not veterinary advice. I am a cat with opinions, not a veterinarian.