Anyone who sat down to watch the Westminster Kennel Club dog show this week probably likes dogs, and might even have one. That’s why Pedigree brand dog food has been the event’s major sponsor for the last 24 years, even though it’s unlikely that the dogs in the ring eat such pedestrian fare. This year, Purina has replaced Pedigree as sponsor. Why? Was their contract up? Slashed ad budget? No. It was because Pedigree’s commercials about the plight of shelter dogs were bumming everyone out.