My cats fur has gone yellow on his stomach area. We've given him a bath but its still there. We don't know exactly how old he is as he was a stray. The vet estimated he is between about 3 and 7. The vet didn't mention the yellow belly when we he saw him. The skin isn't discoloured, just the fur. Any ideas what is going on?

Im presuming he's white on the tummy normally? Is it yellow staining? It might be over grooming in that area - white dogs often get yellowing fur around their mouths due to their siliva, cat can get the same thing, but it's more unusual. Do u see him grooming a lot?

Yes he was white on his tummy area before. I've not noticed him grooming anymore than the other cats but I'll keep an eye on him and see if he is.

Urine can stain the fur - are there any continence problems?

dyes from dry catfood?

try wetfood?