Most mother dogs lose their appetite just before they whelp, so they're ready for a meal right after they've given birth. Yours should have gotten extra food during her pregnancy, and she'll continue to need extra nutrition while she's nursing. Once you've cleaned up the whelping box and your nursing female is settled comfortably with her puppies, she's ready to eat.
As your mother dog delivers her last puppy, you'll be busy making sure the early pups are warm and well. You'll know when the mother has finished whelping because she'll look around for her brood, check to make sure they're all with her, perhaps do a few turns in the whelping box and settle in to nurse. She'll look content but exhausted; the look of anxiety she wore when puppies were coming will be gone. Give her a few minutes with her puppies, then take her out to potty before returning her to the whelping box.
Preparing to Eat
It's likely your mother dog didn't eat much the day before delivering her pups. Many pregnant dogs begin to refuse food about 12 hours before they whelp. She may have vomited just before whelping. Offer her a small bowl of water after she's delivered her last puppy before you take her out to potty. Once she's been out and is back in the whelping box with her puppies, make sure she's nursing the puppies. She'll be too anxious to eat if her puppies are crying or looking for her. Place each puppy on a nipple, if necessary, to get them started.
Put together a small meal for your mother dog. Her first meal should be light but nourishing. Mix canned dog food, warm water, and vanilla ice cream or cottage cheese. Give her about half of her regular meal size, then let her rest with her puppies for a few hours. Offer her a bit more food -- again, about half of her normal meal. Don't feed her too much at once. Small meals for the first 12 hours after whelping will be easier for her to digest.
Feed your mother dog three to four meals a day in the weeks after whelping her litter. She will need extra nutrition during this period to feed her puppies. Feed her puppy food, which will supply extra nutrients during this period. The American Kennel Club recommends increasing a mother dog's food while she is nursing by 25 percent per puppy. Add some cottage cheese for extra calcium. Be sure she has access to water at all times in the whelping box. Hang a water pail from the side of the whelping box to avoid leaving it on the floor where a puppy can reach it.