Cats and dogs are different!
Dog and cat foods are formulated differently because dogs and cats have different nutritional needs.
Complete and balanced pet foods provide all the nutrients required in the correct ratios for the pet. Dog foods provide all the nutrients a dog needs to stay healthy but they are not formulated to provide the additional nutrients that cats need in their diet. Although we often refer to both cats and dogs as carnivores (meat eaters), in fact the dog is a semi-carnivore and the cat is a true carnivore. This means that cats must have certain nutrients in their diet that are only found in meat. Dogs can survive on a meatfree diet. Cats have specific nutritional needs that dogs do not have. A diet designed for dogs may not provide the same nutrients at sufficient levels for cats.