Auggy Doggy's appetite is down

Auggy Doggy has not wanted his breakfast for several days now. He is 10 years old and this IS unusual for him. He was recently on Rimadyl, for about two weeks, but I have eliminated all vitamins and pills from his food. He gets a quarter cup of ground beef, (fried) and a level cup of Acana dry kibble with warm water, to make a warm moist meal. It is usually his favorite, but not a bite in the morning, but eats it all in the evening. He gets exercise every morning before chow, and drinks, pees and poops like normal. Ideas???