Caring For and Feeding Orphan Kittens
Unfortunately, events sometimes happen that make it necessary to hand feed kittens. Sometimes something happens to the mother cat, or she becomes incapable of feeding them for some reason, or produces an inadequate milk supply. In the photo above, the kitten's mother died giving birth and so it was hand fed.
Sometimes orphan kittens can be placed with other mother cats who are nursing their own young. If this situation isn't available the orphaned kittens will need to be hand fed. Keep in mind that a kitten's immunity is derived from their mother's first milk (the colostrum) and if they were not fed by their mother at all they will be at an increased risk of developing an infection. You should speak to your veterinarian about this.
Also, newborn kittens must be kept warm. Thermostat temperature controlled incubators are best. If you don't have, or can't get one of these, you can put an overhead light over them to warm them. You can also use heating pads, but only if they are on the low setting, are well covered with towels so they don't burn the kittens, and only if they only partially cover the flooring of the box you are keeping the kittens in so that if they get too hot they can crawl off of the heating pad to cool down. Using overhead heating is preferable to using heating pads. The temperature should be about 85-90 °F (30-32°C) for newborns and after a couple of weeks you can lower the temperature some (to about 80°F or 27°C). You should keep the air temperature in your house rather warm while caring for orphan kittens (close to the same temp as needed for the kittens). You should place a thermometer (without mercury in it of course) in their box so that you can monitor the temperature of the kittens' surroundings.
What to Feed Orphan Kittens
Don't use cow's milk to feed newborn kittens. There are kitten milk replacement products available that are much better, such as Just Born Kitten Replacement Formula available from Petco (and other places). These replacement formulas are closer to that of a mother cat's milk. You can buy these premixed or you can buy the powder and add the water yourself. You can refrigerate the unused portion for about 48 hours. Follow the directions on the package as to how to make and store it.
You should weigh the kittens on a gram scale (your bathroom scale isn't going to be sensitive enough to measure small weight changes in the tiny kittens) and follow the directions on the kitten formula as far as how much to feed per a given weight. Adjust the amounts depending on the needs of individual kittens. Overfeeding typically results in diarrhea and underfeeding results in dehydration and a failure to gain weight. Underfed kittens may cry continuously or lack energy. Remember that kittens dehydrate quickly and dehydration can be quite serious. You should weigh the kittens daily to monitor their progress. They should gain a small amount of weight each day and their weight should double by the end of the first week.
Newborn tiny kittens generally need to be fed about 5-6 cc's six times a day spread out evenly throughout a 24 hour period, which comes out to about every 4 hours (and yes this includes in the middle of the night). As kittens get older they will eat more formula, but less often. Follow the directions on the kitten formula as to how much they should be fed per their weight. If this information isn't given call your veterinarian's office and ask them for their advice.
How to Feed the Kittens
To feed newborn kittens you can use a syringe with no needle, as in the top photo, you can obtain a special pet nursing bottle, or you can use an eye dropper. Small, weak kittens that are unable to take milk through either of these methods will need to be tube fed, but before you attempt this have your veterinarian show you the proper technique. Otherwise you may accidentally hurt the kitten you are trying to save. You can probably obtain the tubing device from your veterinarian as well.
Whatever method you are using to feed the kitten, keep the kitten upright (as in the top photo) and not on its back while it is feeding. Laying the kitten on its back will cause it to aspirate the formula into its lungs.
The formula should be warmed before giving it to the kitten. Never feed cold formula to a kitten. Make sure it isn't scalding hot either. Test the temperature on your arm or wrist like you would do before feeding a human baby. Also, make sure the kitten is thorougly warmed up before trying to feed it. Don't feed kittens that are cold. Warm them up first.
As mentioned earlier, overfeeding leads to diarrhea. This is because overfeeding causes the formula to move through your cat's digestive system too quickly. This can even cause the kitten to lose digestive enzymes, which then causes the kitten to be unable to digest the formula at all. The color of the diarrhea can also tell you something. If the kitten's stool looks like curdled milk then this is due to prolonged overfeeding and a loss of digestive enzymes. Green stool means that there is too much bile in it. If your kitten has diarrhea you should contact your veterinarian or local animal hospital for advice (and describe the color of the diarrhea to them even if they don't ask).
Stimulating the Elimination Reflex
Also, remember that after each feeding you will need to stimulate the elimation reflex since the mother cat isn't available to do it. Kittens can't eliminate waste on their own. Someone must help them to do this. You stimulate the elimination reflex by wetting a cotton ball or gauze pad with warm water and massaging the kittens anal and genital areas. You should do this after each feeding for about 3 weeks.
Finally, you should keep the kittens clean. Their mother isn't around to do this and so make sure that their bedding and bodies are clean. Don't bathe them, but you can clean them with a warm, wet, gauze pad or cotton ball.
If your kittens have any problems you should call your local veterinarian's office or animal hospital. They can often give you advice over the telephone and will tell you if they feel the kittens need to see the vet.