For her health she should not have more than three, and she should rest a year between litters. She should not be bred before two years of age nor after six years of age.
It depends on the dog (as in animal not the male dog). A good pointer of how many pups a dog might have, if it's a pedigree bread is to look back the parential line as it will list the pups born to...
It is seriously said that a German Shepherd should only have two litters a year but any dog should only be bred three times in their life. The more litters a dog has, the less healthy she will...