If you have a new, little puppy that is sick and vomiting; he needs to see a Vet immediately. I would say, yes, the cat food could have made him ill.
These little ones dehydrate very quickly and can go down very quickly.
Since you just brought him home; I'm assuming he is young and small. I would take him to a vet sooner rather than later.
Please keep us posted on how he is doing.
__________________  Mommy to Lucy, Ringo, and Matthew |