How long after my female cat/dog has had kittens/puppies can I get her spayed?

Mother cats and dogs can become pregnant while nursing. It is important to keep a nursing mother away from other adult cats/dogs of the opposite sex. You can spay a mother as soon as the kittens or puppies are weaned, (5 to 6 weeks for kittens and 4 to 5 weeks for puppies).