[Michael Romanos]

You've got it. Your Corgi was not eating his food quickly, because even he was telling you - it's too much, and (maybe) too boring.
There are a lot of excellent and important vitamins and minerals etc in cereals and of course, the right kind of milk is excellent for calcium and puppies need calcium for good, strong bone growth.
I wouldn't give a dog a run of the mill cereals- such as corn flakes, puff rice , etc etc (many contain sugar and salt and other elements that are not particularly beneficial, but there are three excellent types of cereal for human babies and for Corgi puppies. In order of preference - Complan, Farex and Baby Rice (Robinson's - if the brand name is available overseas). Grain food is great for dogs - and my Taylor sometimes gets a whole piece of toasted (but not buttered) grain bread.