dogs

Question
does it harm a dog to drink milk

Answer
Technically, no. Cows milk, however, will cause diahhrea in puppies and some adults, small breeds especially. If you're trying to add calcium to the dog's diet, you would do better adding cottage cheese or yogurt.  Goats milk, on the other hand, is great for sickly or weak puppies, in moderation of course.  Powdered milk is ok, but I need to ask why you're concerned I guess.