I know there have been other discussions about messy bottoms but my baby seems to have a different mess. My cat is a big boy and is 5 years old. He can groom himself back there with some difficulty. About 2 months ago I noticed his bottom was a little crusty and irritated. This is the messy I am referring to, he does not have diarrhea. He also started scooting his bottom on the carpet. I assumed this was his anal glands or worms and took him to the vet, who said the anal glands needed expressing and he had no worms. He was given a blood test and everything was normal. I assumed it was the anal glands. The irritation then went away and the butt scooting went away. Well now all of it is back. I did start the change over to grain free food about 2 weeks ago but he had this problem before with grained food. He is acting normally with no issues. As with a human, I think he may just need some fiber in his diet. The vet suggested canned pumpkin but he wouldn't touch it. Any other suggestions for fiber?