The short answer is, yes, your cat can eat dog food in an emergency.
There’s nothing in dog food that’s going to make your cat sick. That’s the good news.
The bad news is that dog food lacks many vital nutrients that cats can only get through their diet. Over time, it’s what dog food doesn't have that will eventually make kitty sick.
Cat’s evolved eating a lot more protein than dogs. In fact, cats are strictly carnivores. Dogs, on the other hand, have digestive systems that are more capable. They can extract nutrients from various types of food that cats can’t. Over time, eating dog food will leave your cat deficient in essential amino acids and vitamins.
The beta-carotene in sweet potatoes and squash works great for the digestive systems of dogs. They have the enzymes necessary to turn that beta-carotene into vitamin A, which can then be put to use in the body. Your feline, however, doesn’t have a digestive tract that's quite so industrious.
Whereas dogs are scavengers, cats are pure hunters. They evolved eating fewer veggies, and therefore aren’t as prepared to process them. Going without vitamin A for a few days isn’t going to kill your cat, but it isn’t going to help her either. Most dog foods don't have enough vitamin A for your cat.
Image credit: Christina
Taurine is an amino acid that cats can only get through what they eat. Cat food has plenty of it. Dog food, on the other hand, tends to have very little.
Similar to vitamin A, going a short while without it isn’t going to kill your furry friend, but over time a taurine shortage can be devastating to their health. If left unchecked, taurine deficiency can result in a serious heart condition known as hypertrophic cardiomyopathy. Get that kitty back on the taurine train ASAP!
Dogs have crafty digestive systems that can synthesize arachidonic acid on their own. Cats are not so blessed. Get your kitty back on cat food as soon as you can before she runs low on this critical nutrient.
Relative to their weight, cats need to eat roughly twice the amount of protein that dogs do.
While humans and dogs can get the nutrients they need from fruits and vegetables as well as meat, cats are strictly carnivores. All the amino acids that they need are found in the meat they eat. They can’t get them any other way.
When it comes to the amino acids that your cat’s body craves, dog food just doesn’t have what it takes. You can feed your cat dog food in an emergency, but keep in mind that your cat has a short timeline for staying healthy without access to food that’s designed specifically for her. Chocolate is another food you'll probably want to avoid giving your cat in large quantities.
Cats are hunters, kings of the jungle. They need a diet that's fit for animal royalty. One that’s rich in the amino acid taurine, has ample vitamin A, plenty of arachidonic acid, and enough protein to drown a lion.