Best food for a nursing mother?

It is VERY important for a mother dog to eat a high quality, (no by-products, wheat, corn, soy) dog food, which would exclude most of the food sold by vets. Nursing mothers should be fed puppy food because it's richer and they need extra calories. She should eat three or four times a day until she's done nursing to help her produce the milk the puppies need. Both the dam and puppies can become ill if the mother is not fed properly. My dogs eat Fromm Gold Puppy Food during and after pregnancy, available on www.chewy.com.

Here's an article by the AKC that helps to explain the dam's need for extra calories and high quality food.
http://www.akc.org/content/dog-bree...e-and-feeding-of-the-breeding-bitch-part-two/