It’s very important to know that an actual newborn kitten should never eat solid food. The best thing for a newborn, like with human babies, is mother’s milk. Once a kitten is between 6 and 8 weeks old, you can start the full transition to solid food. While your cat is a kitten and after it grows up, you should never give it cow's milk. Most cats and kittens cannot digest dairy. Any food given to your kitten or cat should be made explicitly for felines.
If the newborn kitten has been abandoned by its mother, you can feed it with a bottle, a syringe, or a dropper until it is 4 weeks old. Only fill it with milk replacement liquid that is designed for kittens, since milk from a cow will make kittens sick. Kittens need to eat every couple of hours, slowly lessening the frequency and increasing the amount of food as the 4 weeks goes along. Take your kitten to the veterinarian to be weighed, which will determine the specific amount of food and the specific schedule of feedings that your veterinarian will recommend.
Feed your 4-week-old kitten either wet cat food or dry cat food soaked in water and mashed with a fork. This will be easier to eat and digest.
Give your kitten only food and treats that are formulated specifically for kittens. Adult cat food and treats can be more difficult to digest.
If the kitten is still with its mother, you should wait until it is about 6 to 8 weeks old before adding solid food. Give your kitten 1 tbsp. of solid food five times a day to start. At this point, the kitten will also likely be drinking mother’s milk, too.
Increase the amount of food you give your kitten as you take the mother cat away during meal times. Don’t do this all at once. For a week or so, take the mother away for about two of the daily feedings. Each week, take her away for one more. By the tenth to twelfth week, she should no longer be producing milk and your kitten will have been weaned onto only solid food.