Why Other Pets' Food Fails a Domestic Shorthair
A Domestic Shorthair cannot stay healthy on food made for other kinds of pets, however enthusiastically she eats it. Cats evolved as strict meat-eaters, and their bodies have handed the job of supplying several essentials entirely to their diet: taurine for the heart and eyes, a ready-made form of vitamin A, and fatty acids that dogs can build for themselves from other ingredients. Dog food, quite reasonably, is not built to feline specifications, so it delivers too little of those essentials and too little protein overall for a cat. Food for rabbits, guinea pigs, hamsters or birds points the other way entirely, being fibre and plant matter that a cat's short digestive tract is poorly equipped to use. A Shorthair on such a diet may look fed while becoming quietly deficient.
The Difference Between a Bite and a Habit
Context matters here, because nearly every cat in a multi-pet home has stolen something. A single mouthful of dog food, or a raid on the rabbit pellets, will pass through a healthy adult Shorthair without consequence beyond the odd loose stool, and there is no need to panic or to induce anything. The habit is the hazard. Deficiency builds over weeks and months of substitution: the cat whose main meal is really the dog's food, topped up with a little of her own, can drift toward poor coat condition, low energy, digestive trouble and, over a long period, more serious taurine-related problems that a vet would need to assess. Treat any pattern where she prefers or relies on another animal's food as a feeding system to redesign, not a quirk to laugh off.
Running a Multi-Pet Kitchen Safely
Give each animal its own food, feeding station and finishing time. Cats cope well with eating up high or behind a door left open only cat-width, while dogs are fed where they cannot wander to the cat's bowl mid-meal; most dogs inhale their food and then go looking for the cat's, so supervise or separate until bowls are lifted. Timed meals, rather than food left down, end the all-day buffet that makes cross-eating invisible. Store each food in a labelled container with its own scoop, and brief anyone who feeds the animals, because a well-meaning guest will otherwise feed everyone from the largest open bag. If your Shorthair persistently angles for the dog's food, check that her own meals are enough for her size and that the food is fresh and palatable; a cat abandoning her bowl often has a reason worth finding.
When to Involve Your Vet
Call your vet if your Shorthair has been eating another pet's food as a substantial part of her diet for weeks, if she loses weight or her coat roughens, if her eyes or energy seem off, or if vomiting and diarrhoea follow a big raid and do not settle within a day. Bring the details of what she has actually been eating and for how long; that history is the most useful thing you can hand over, and it is far easier to reconstruct from a household that tracks feedings than from memory. Going forward, a single written rule in a place every feeder checks prevents the slow drift from happening again. Through KinsLe Family Sharing, your Domestic Shorthair's feeding rule and usual food sit on the profile the whole family shares, so the cat-food-only message reaches the teenager, the grandparent and the neighbour alike.