Nursing Pregnant Cat

Question
I have 2 female Persian cats.  My one cat had her litter of kittens about 5 weeks ago and my other female is due with her litter within the week.  The thing is that the pregnant cat has taken to nursing the other litter, caring for them as if they are her own, from cleaning them to protecting them to feeding them.  My concern is, will her feeding this litter from time to time harm her unborn kittens.  I understand that she will not be able to feed this older litter and her own newborns as the older kittens will push the smaller kittens away, I am just wondering on any health issues.

Answer
Sherrie,

Here's the problem.  Now that the older litter has caused milk production to speed up, if they are removed from the pregnant one too soon, I am not sure her hormone production from now until birth will keep the milk flowing.

So, I would let them nurse for now and just before you think the new litter is going to be born, you can separate them from the pregnant female.  At that time, I would also wash her nipples in a mild shampoo or soap and thoroughly rinse them.  You do not want the scent of the older kittens on any of the nipples when the new borns come out.  New borns seem to latch on to a nipple and "claim it". This appears to be done by sense of smell.

Furthermore, you do not want the other female in their while the birthing is going on, just in case she decides she would also like to nurse the new borns!!!!!

I would also begin weaning the older litter at this time, so, when the new ones are born, the older litter can be well on its way to eating solid food.  They too should be relocated to another area once the birthing begins as they can really get in the way of the pregnant female birthing her new litter.

Good luck and best regards... Norm.