Can adult cats become sick if they eat kitten food?

by Julia Prokipcak
(Ottawa, ON, Canada)

Almost two months ago, we got a new kitten and for the first while, since she was adjusting, she stayed in my bedroom at all times. After the first few weeks, we let her out to play with the other cats, and eventually started to feed her with them.

After a while she became interested in the adult food and the adult cats were then able to steal her kitten food instead. Fast forward about a week and one of the adult cats threw up and had a very liquidy poop outside of the litter box.

A few days later the second adult cat has been coughing and trying to throw up but shes been unable. I got her hairball medicine so she would be able to throw up so now she has three times, as well as had her own liquid poop (on my bed...)

I was wondering if the kitten food could have caused this? And if so can I switch the kitten to adult food fully? The kitten is 4 months old.

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Jul 25, 2018
Might be too rich
by: Kurt (Admin)

I'm sorry to hear your cats aren't feeling good. Any rapid change in diet can cause gastric upset in a cat. As a rule, kitten food is higher in nutrition than adult cat food.

Because of that, veterinarians will often recommend adult pregnant or nursing cats be fed kitten food.

It may be too rich for your adult cats, though, or your cats may be vomiting and have loose stools for another reason.

If these were my cats, I'd continue to feed kitten food to the kitten to support growth as kittens need the extra calories from fat and protein. I'd also see if I could set up meal times for more control over who eats what, how much, and when.

As always, if you suspect your cats are ill, a call to the vet is recommended. I hope this passes quickly for them.

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