[Mikey T]

Puppies are not, but most dogs are lactose intolerate. The do not poses the the enzyme to break down lactose. I would image lactaid or similar products used to ease lactose intolerance in humans would also work with dog but never saw the need to test the theory.

Dog Food FAQs: Supplements/Foods to Avoid/Allergies

Should I give my dog milk?
No. Most dogs are lactose intolerant. Lactose intolerance is a common form of maldigestion. A puppy has the enzyme lactase, which breaks down the sugar in milk called lactose. However, as a dog ages, he generally stops producing lactase. When your dog consumes milk products, the lactose is not digested and the symptoms of maldigestion occur.