I don't know anything about the vitamins, but my vet RECOMENDS cottage cheese for my yorkie. The "Safe Diet" for his upset tummy was 50% white rice and 50% cottage cheese in a bowl.
You could go all-out and totally spoil your dog by mixing his dry chow with cottage cheese, I'm sure he'd love it! In fact, he might never eat his boring old dry chow again
Just make sure you aren't feeding him more CC than regular food I'd think.