A newborn puppy cannot control its body temperature and must be kept in a warm environment. Chilling will stress the puppy and predispose it to infectious disease; overheating can kill it. The environmental temperature can be controlled with a well-insulated electric heating pad or a heat lamp. But make sure the puppies have a cooler place to crawl to if they become too warm.
Keep Your Puppies Warm, Fed, and Clean
Nursing: The first milk produced by the bitch after whelping is called colostrum. Every puppy needs to ingest colostrum as early as possible after birth and certainly during the first 24 hours of life. Colostrum contains a number of substances that are beneficial to the puppy, including immunoglobulins that protect newborns from the infectious diseases to which the mother is immune.
Caring for your bitch after whelping: Some bitches eat very little for the first day or two after whelping. Then their appetite and need for all nutrients rises sharply and peaks in about three weeks. During this entire period, adequate calcium, phosphorous, and vitamin D must be fed to avoid the onset of eclampsia. Optimal amounts of these nutrients are already present in a high-quality diet so further supplementation is unnecessary. After whelping, the bitch ideally should be about the same weight as when she was bred, but not more than 5 to 10 percent heavier. For three weeks after whelping, she will need two or three times more food than her normal maintenance diet to help her provide nourishing milk to her puppies. This food should be divided into three or four meals. The composition of the food should be the same as it was during the last third of her pregnancy; only the amount per day should change.