Is it okay for me to wait until my cat has finished all the food in his bowl before refilling it? Experienced cat guardians will know the answer which is NO for wet cat food and YES for dry cat food provided there is not too much of it in the bowl.
The simple reason being that wet cat food goes off and a domestic cat won’t eat it after it has been out for several hours. That’s my experience anyway. How fast it goes off depends on the ambient temperature. In fact my cat finds wet cat food okay after several hours but there is a limit. He rarely finishes off the entire bowl.
I suspect that most cats do not finish off what’s in the bowl unless the quantity is relatively small and the cat is relatively hungry!
“[Wet cat foods] are not suitable for free-feeding. Once opened, they quickly develop an unpleasant smell that is even more unpleasant for the cat. Canned cat food should not be left out for more than about 20 minutes…” – Cat Owner’s Home Veterinary Handbook 3rd edition page 498.
This advice above in quotes is good but a little extreme for me because it depends on the ambient temperature. Also in my experience wet cat food can last for several hours before it ‘goes off’. Perhaps it also depends on the quality of the food.
Dry cat food
Dry cat food is far more durable in ambient temperatures which is why it is so popular. It is hugely convenient. It is not wise to continually top up the food bowl as it becomes unhealthy with saliva.
Cats will certainly finish off a smallish bowl of dry cat food. However, it is almost universally agreed that domestic cats should not be feed dry cat food one hundred percent of the time as it can cause the cat to become dehydrated. Cats don’t naturally compensate for the lack of water in the food by drinking more. Also some vets think it can bring on feline diabetes because of its high carbohydrate content.
I have my doubts about dry food being safe to leave out. I have always had a mixture of cats, with different needs, so free feeding has never been an option.
Dry food left out and partially eaten will contain grain, which is prone to fast growth of harmful fungal spores. Add to that, the fact that the food the cat has not finished, will always have some cat saliva on it, I think it is a risk not worth taking.
Bacteria from feline saliva will grow, die and different bacteria can grow, maybe bacteria that will be harmful to the cat. Greedy gobblers and delicate, occasional nibblers do not make good companions in ensuring good nutrition or prevention of obesity in the multicat home.
Cats have very strong stomach acid, amylases in the gut which can cope with many types of bacteria. But, modern kibble is a very fertile ground for thriving bacteria that may be toxic to our precious companions.