How many years was lassie show on tv?

In first-run, as opposed to reruns-which are still around. Lassie lasted l9 years! Obviously different dogs were used. the program had the same sponsor- Campbell"s Soups- for the duration of its lengthy run. It was unusual as a juvenile series program that was steeped in borderline tragedy. While episodes eventually came out okay, there was an almost chemically vacuum purity against comedy or even comic relief. everything was Heavy, Heavy, dark cloud society indeed! No other kiddy program, with the possible exception of religious programs- had such a down angle. I can"t recall any even as I said Comic relief in this animal drama- quite different than most Animal shows. Even my mother admitted it was ( Too pitiful) and she liked the show.