The ASPCA cautions that milk produced by cows is not suitable for puppies because it can cause diarrhea and digestive discomfort. Many dogs are lactose intolerant, which is why giving them dairy products, such as cow's milk, often causes loose stools and gas, according to Dog Food Advisor.
The mother dog's milk provides all the nutrients that the puppy requires for the first month of its life. If the mother dog is not available, it is necessary to use a commercial canine milk replacer that is specifically formulated for puppies. Improper bottle feeding techniques can be harmful to a puppy, so a veterinarian should be consulted before feeding begins.