Is any familiar with Betty's early 1970s series, "The Pet Set"? I was surprised to find an episode of this show on the new Season Four "Doris Day Show" DVD set. The reason it was included is because Betty had Doris (and Doris's pets) as a guest. I was not familiar with this show before.

never heard of it. Was it a sitcom, a variety show, a talk show, or what?

IIRC, it was a talk show format where she invited celebrities and their pets on. She discusses "The Pet Set", and all of her other television series, in her wonderful book "Here We Go Again! My Life in Television".