My 6 month old kitten needs help

I have a six month old kitten that weighs at her last vet visit on monday 2.6 lbs. Im aware that this is abnormal and that a kitten her age should weigh around 6-7 lbs. I've had the vets run several stool samples on her all of which came up negative. Even so she has been treated for the normal intestinal parasites as well as coccidia and giardia because she has had some diarrhea that doesnt really ever seem to resolve itself. She eats holistic food has been tested for FELV/FIV and is negative for both. And due to the fact that this has been going on for months the vet doubts its FIP. I also have four other cats who are all the picture of health and have NONE of the problems she is experiencing (diarrhea, weight loss). This all seemed to start after she was spayed in late Sept. Is there any correlation between her pediatric spay and her seeming inability to absorb nutrients properly. Thoughts as to the next move? Both vets I have consulted are stumped and call her a medical mystery.

Have any blood tests been done? What food are you feeding her? Has the vet thought of food allergies or IBS?

Oh, and welcome to The Cat Site.

Unfortunately these types of problems are fairly common in cats. I have a cat that is 7 and started with these types of problems when he was 18 monthes old. There are specific tests, blood and ultrasound, that can be done but sometimes you have to look for a vet with the resources to do the needed specific tests. Those tests will also be on the pricey side.

Only kitten I have had that was that small (proportionally that is) was a liver shunt kitten who was sickly and euthanized at 7 weeks old. she was not even a pound.

May want to at least look at numbers to see if it indicates anything. Test cost about 20 bucks(at er vet near me so may be cheaper by you) to check ammonia level in blood. That would at least indicate if livers involved

All the others have been normal for the most part tho, and I have a lot. I would lean to stress of the spay triggered something off in her.

has this parasite been checked for? http://www.highgait.com/page/page/3485008.htm

I too suggest blood work...

Is the cat proportioned to its current wt ?
I again ask what food? see many foods do not agree with younger kittens or a specific cat

Blood work is being done tomorrow. As far as her size to weight ratio: she's tiny for her age but its more of a growth stunt than a genetic condition. Besides that she is still extremely thin. You can easily feel her ribs and spine despite eating like a normal kitten. The only reason I'm leaning toward the spay along with one of the vets that I work with is due to the fact that I have had her since she was 7 days old and raised her on the bottle. She was in PERFECT health before her spay. She eats the Wellness Kitten food. Any other thoughts besides blood work? The vet thinks we wont find much there

wellness is good... does she get wet food

How long was she on formula for and did you notice when you stopped th formula she started losing/not gaining as well?
Did she have and bloodwork before the spay?

Personally, I would shift her to a meatier type of dry or canned food. Cats are true carnivores and Taste of the Wild and even Chicken Soup for the Kitten Lover's Soul have been the favorite of my crew. I don't go for the food where the majority of the contents are garden vegetables and fruits flavored with a bit of meat. For my dogs, yes, but not my cats or my kittens. Don't get sucked into the holistic approach- it truly isn't the best food out there no matter what they claim.

There is a product that one of my cats was put on as a kitten. Its called Prozyme and it help animals absorb the nutrients in food. Its a powder that is sprinkled on soft food. It will certainly not hurt her or any of your cats in anyway. Is she eating canned food? Good luck

http://www.petco.com/product/13434/Prozyme.aspx