I agree with Kairapup 100%, maybe some diarrhea, or gas? How did she do after all? It isn't higher in fat or protein (I guess it depends on what you feed now?)
Meow mix is like McDonalds, it is garbage, even when it becomes cat poop. Read the ingredients some time. I swear that is the kind of food that is not properly digested, and makes dogs want to eat it as poo. Ack!
I would definitely keep it away from your dog like you did.
When I fed cats kibble I fed them on top of the washer, because they did love it. I sometimes actually use cat kibble as training treats. I use stinky fish stuff, but it is a little better brand.