Colostrum
A newborn fawn should get colostrum in the first 24 hours of life. Colostrum is the fluid the mother produces before her milk comes in; it contains antibodies to protect the fawn from infections. If doe colostrum is not available, frozen or dried cow colostrum may be used. If no colostrum is available, give the fawn water at first.
Milk Replacer
Never feed a fawn cow's milk -- it is not rich enough, and it can cause digestive problems in deer that can result in death. There are several brands of cervid (deer) milk replacer on the market, but lamb milk replacer is the nearest alternative to deer milk. A foster mother, such as a goat or another doe, is a better idea than bottle-feeding, if one is available.
Nursing
Use a regular baby bottle with a lamb nipple to feed an orphaned fawn, but don't enlarge the hole in the nipple, even if the fawn seems to be struggling to get the milk. Guzzling (drinking too much too fast) can cause bloating and diarrhea, which can be fatal. If the fawn won't take the nipple at first, try putting the nipple into the side of its mouth and letting it chew on it until it gets the idea. Feed it several small amounts a day that total no more than 20 percent of its weight -- every five to six hours on a regular schedule should be adequate, unless there are problems.
Weaning
Fawns will take a bottle as long as it is offered, but they are capable of digesting solid food at about five weeks. Start with fresh green food, such as dandelion greens or tender grass, and progress to deer pellets, grain and hay. The fawn should be completely off milk by four months of age. Apple slices make a nice treat.