We're just a bit worried. You may remember that R repeatedly had abnormal blood tests starting in September. They seemed to indicate cancer - but an ultrasound and an echocardiogram did not uncover any tumors. We decided to take a wait-and-see approach, while we began feeding R a home-cooked diet designed by a veterinarian who specializes in nutrition.
After more than 2 months on the new diet, I took R to the vet to have his blood examined again. Unfortunately, it was worse than it has been in the past. The abnormalities are now suggestive of leukemia or lymphoma so his blood is presently at the Colorado State University Vet School where they're doing high tech tests to look for those two diseases.
In general, R's energy and spirits have seemed pretty good. He likes playing with his sister, most of the time.
I've felt, for months, that something intangible wasn't quite right with R. Our vet suggested that it was the loss of K that provoked the change that I think I see. It's possible that she's right.