Eating dog isn't inherently disgusting, or at least not any more disgusting than eating other animals. A lot of Native American tribes used to eat dog. I imagine that was how they kept their dog population in check, since they couldn't spay their dogs. Lewis and Clark's expedition also ate dog (except Clark, who couldn't stomach the idea) and grew to like it. They thought it was very healthy and invigorating, too.
Anyway, this dog died of natural causes (at a puppy mill, it sounds like . . . poor thing.)