My dog is going on Z/D Ultra next if his current food doesn't work for him. You might want to try Eukanuba Response FP, or KO. Harley was on the FP which is fish and potato before we realized that he is allergic to fish. He loved it (he was constantly sniffing the bag) and he had no trouble digesting it, which is his biggest problem. We were going to try KO next which is Kangaroo and Oat, but they have fish oil in it. This is probably a better quality food and your vet should be happy with it. My dog actually has never had any problems digesting any Eukanuba products, unfortunately they put fish in everything for the Omega 6's.