Did your vet do any blood, urine and/or fecal tests? Which NutriSource recipe are you feeding currently? My dogs like and do well on Whole Earth Farms Pork, Beef and Lamb formula. It does not contain chicken or wheat. It must be tough seeing your old guy not eating.
I was having the same issue with my senior cat and she was prescribed an anti-nausea medicine and a steroid which helped almost instantaneously. I am currently weaning her off of them and hoping she will not have to continue it for a prolonged period.
He might be having some stomach issues or problems digesting kibble as Susan mentioned above. If you are interested in making a homemade cooked balanced diet, check out http://www.balanceit.com. It’s a great resource for homemade diets run by veterinarians.
Good luck!
