I have a 6 year old shepherd mix, always had a sensitive tummy. The past couple years she has been having frequent bouts of mucous and bits of blood in her stool. The vet indicated colitis or ibd. She doesn't vomit frequently, sometimes when her tummy is upset. She has always taken metrodiozole and it settles it down for a week or two then back to soft stools again. Last week the vet changed her food to Science Diet I/D, he thinks this is her issue. Many stool samples and nothing shows up but a drop or two of undigested fat. He thinks she cannot tolerate fats in her diet. I am changing her food slowly, but she has been taking the pills, one twice a day for almost a week. Any advice?