http://www.med.umich.edu/1libr/yourchild/feed.htm

This is a good article about feeding nutritious food to children.

  the American Academy of Pediatrics recommends that children:

• 1-3 years old get about 2 servings of milk (low-fat milk after age 2 years)
• 4-8 years old get about 3 servings of low fat milk
• 9-18 years old get about 4 servings of low fat milk

After age two, most kids should switch to reduced fat milk (skim or 1% milk fat). Even kid's arteries can clog up if they eat (or drink) too much saturated fat. Talk to your pediatrician about how much milk your child should be drinking.

To reduce the amount of milk or juice your child takes in, try diluting your child's milk or juice with water, and each day gradually adding more water until your child is drinking plain water to quench their thirst. This will help them make the change little by little.

milk is definitely great for kids, as it has protein for strength and growth, calcium for strong bones and teeth, and vitamins A and D for eyes and bones. Children older than one year should have two or three 8-oz servings of milk every day.

Cow's milk is not recommended for babies. After children turn one, they should drink whole milk for at least one year. The fat in milk allows kids to grow and helps their brains to develop. If you have an overweight child, ask your doctor about using 2 percent milk. Toddlers should not drink nonfat or skim milk.

Some children drink too much milk, especially if they use a bottle instead of a cup. Try to get your child to drink 2 cups of milk each day, then add variety with other healthy dairy foods.

The 2005 Dietary Guidelines recommend consuming at least three cups per day of fat-free or low-fat milk or equivalent milk products.

But I think that is for adults. 

But what if a child is allergic to milk and can have none at all.. How tomake sure that he gets enough calcium?

If your child is allergic to milk, it is possible for him to get the calcium he needs from other calcium-fortified foods and beverages, like soy milk, juices and breakfast cereal, as well as some unusual food sources like broccoli and turnip greens.
 
If your child is aged between 5 to 8, he needs 800 milligrams of calcium per day, while 9- to18-year-olds need 1,300 mg of calcium, or the equivalent of approximately 4 cups of milk.
 
Because the percentage of Daily Value (%DV) on food labels is based on 1000 milligrams per day, it’s easy to determine how much calcium is in a serving of many foods you buy: simply multiply the %DV found on the food label by 10. For example, calcium-fortified orange juice has a %DV of 30, which means it provides 300 milligrams of calcium per 8-ounce serving — about the same as milk. This only works for calcium, though. The %DV for other nutrients is based on different values.