Introducing strange kittens to lactating female

Question
Hi Jessica--I am a foster mom for the Spay and Neuter Task force.  We trapped a feral mother with 5 kittens.  As it turned out she is not feral, very nice and very pettable.  We have two motherless kittens the same age as hers and would like see if she will care for them and feed them along with hers since she is in nice shape and getting lots of good nutrition.  How should we introduce her to these kittens?


Answer
Hi Darcy.  Just put the kittens with her.  I've never yet had a lactating mother reject foster kittens.  I've even had mothers who are nursing 8-week-old kittens nurse 1-week-old kittens.  Of course, if there's any hissing, then I would say it would be best to bottle feed the babies or to find another foster.  However, I sincerely doubt this will be a problem.  I just put a one-week-old with a mother and her three-week-old kittens this past weekend, and the mother immediately groomed her and nursed her the instant they were put together.

Of course, I would only recommend this is mama has been cleared of feline leukemia.

Also, you need to pay special attention to the foster babies' weights.  Weigh them daily with a mail scale to be sure they gain 1/4-1/2 oz daily if they are 2 weeks or younger, and 1/2-1 oz daily if they are 3 weeks or older.  If the kittens lose any weight at all, it's a sign of Fading Kitten Syndrome.  This can be caused if the mother's blood type is A and the kittens have blood type B.  A blood type B kitten's antibodies will attack blood type A antibodies, which the kitten receives through the breast milk of a blood type A mother.  If any weight loss is noted, it should be assumed that their blood type may be the problem.  Blood testing is available, but it's expensive and results are slow.  If blood type is the suspected problem, the kittens should be removed immediately and  be bottle fed and not tried on another foster.  That's because the overwhelming majority of cats are blood type A.  Blood type B kittens will be difficult to find a safe foster for.  Blood type A kittens are generally able to nurse safely from mothers with either blood type.