erm, actually i'm not really knowing all of cat problem. but i'm try to give my opinions....
Kalo njis kocin jd cmtu rsanya normal. sbb kalo kocin yg njis dier cair mmg da problem. kalo just kaler warna2 cmtu....myb makanan dier kot.
xtaw la sbb i bkn vet. i just kasi opinion. i pun penah bela kocin mse i kecik2 dlu. just my experience jer.