Underwieght mama cat - please help!

So my neighbors have gone away for a week and asked me to look after the kitties. Mama cat had a litter (her first) about 4 weeks ago. The kittens seem healthy and mama seems to be taking good care of them, but mama seems pretty underweight. I can feel her ribs, her vertebrae and the top of her hip joints by her tail. Her abdomen seems kind of wide compared to the rest of her. Her coat looks ok and her demeanor is fine. Her stools, however, are kind of yellowish beige and one was diarrhea like. I'm not sure if her feces is always like this, but I saw 4 of the same color.

Her parents had me feeding her half a can of wet food (probably the cheapest) in the morning and the other half in the evening. She also has a dish of friskies dry food and water.

Please help me. I'm really worried about the mama kitty.

Thanks

Kara

Since she is feeding kittens, she needs as much as she can eat. If you can afford it, start giving her another half a can halfway through the day. 

I'd increase her servings.  I'd suggest adding some kitten food, but that might disturb her system even more and create a bigger diarrhea problem.  I would let the owners know about her stools and suggest they get her to the vet.  She could have worms.
 

As I have rescued more momma cats than I can count, I have seen that the majority end up looking pretty skinny for a while until they get back their girlish figures,

HOWEVER, sure signs of an underweight/malnourished cat is the hip bones protruding, their spine defined, and her ribs showing.

The likely cause is what is causing her diarrhea. As food is quickly passed through her system she not only does not absorb the nutrients in the food, but loses her body fluids out in her diarrhea.

Over a period of time this will cause an emaciated (skinny) cat.

She very likely has parasitic issues in her intestines, which her babes will as well.

She does need a fecal float done and the proper meds given, as well as SPAYED !!

This will cost about $100.00 total.

I agree about the extra food, she will need to eat more and drink lots when nursing, plus needs all the help she can get as long as she continues to have runny poop, to semi-maintain the weight she has now.

Thanks for caring.

Oh, $100.00 is only for the visit and fecal exam and meds, not for the spay

Thanks. I did increase her feedings. My plan is a whole can of wet food and unlimited dry food when I check on them in the AM. In the evening I've been bringing her meat. Last night was roast beef and today was tuna. I'm working on an idea on getting my friend's cat fixed. She can't afford vet bills, but with having 7 kitties in the house now she better. She won't be back for over a week.

Thanks

Kara