First of all, here is the very simple, clear-cut explanation why cats should not be eating dog food:
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Now. Number one. Dog food should NEVER be left down, not even for the dog. Two-three meals a day (depending on the dog's health status) and no food in between. A small late evening snack is acceptable to prevent early morning vomiting of bile (a problem for many dogs).
So. If food is not left down, the cat can't get to it.
Also, since the cat has developed a taste for dog food, you need to put kitty in a room with the door closed before you serve the dog his food.
After the dog has eaten and the dish has been washed and put away, kitty can come out of exile and start working on his own food.
If kitty sulks and goes on a hunger strike for a day or two, that's fine. Don't worry about it. In a day or two no
health problem can develop. But kitty will get hungry, ready to accept cat food again.
You need to keep them separated at meal times as long as it takes for kitty not to want to eat the dog's food. And then keep doing what you've been doing: not leaving one morsel of dog food down after the dog has finished eating.
For cat food please choose very simple canned recipes that contain ground
catfood. If you wish to feed some dry food as well, look for simple recipes also with few ingredients. And make sure kitty fills up on canned food instead of dry. The dry food should only be a very small part of the diet.
If food for a cat doesn't contain taurine, blindness and heart disease (dilated cardiomyopathy) are the consequences.
Lack of protein (please note: protein requirements for cats are higher than those for humans) leads to hair loss, a variety of skin and coat problems, lethargy, a weakened immune system, weak muscles and abdomen distension.
You also need to keep in mind that because your cat is an obligate carnivore, the protein you feed must be complete protein that contains all the essential amino acids. It must come from animal sources such as meat, fish, chicken, turkey, etc.
Plus, for cats, the B vitamins, minerals and micro nutrients also have to come from animal protein, so when there is not enough protein in the diet, deficiencies of all the other nutrients naturally follow.
Vitamin A for a cat must also come from animal sources.
Vitamin A increases immunity and aides in prevention of bladder, respiratory, and other infections.
Promotes growth, skin and coat health and muscle coordination.
Helps pituitary gland function.
Improves vision, hearing, and digestion,
Provides protection against toxic chemicals in food and water.
Deficiency of vitamin A causes loss of appetite, muscle atrophy, weight loss, dull and brittle coat, scaly hairless patches on skin, overgrowth of the cornea, conjunctivitis, retinal degeneration, intolerance of light, resistance to petting and handling.
In kittens: weakness, irregular muscle coordination (ataxia), tremors, and paralysis.
So, in short, it doesn't matter how great and wonderful a dog food is for your dog, it is not acceptable food for your cat. Your cat needs cat food in order to stay healthy. He will
start eating it again as soon as dog food is no longer available.