Looking for an old TV program about an Indian and a Horse?

My grandpa is looking for the name of an old frogram he watched back in the 70's or 80's. He said it was in color. It was based out on a prairie. There were only 2 characters in the whole movie, the horse and the indian man. The Indian man had never seen a horse before and finds one out on the prairie. The horse was take he thinks, probably got loose from somewhere. The Indian befriends the horse and learns to ride it. My grandpa thinks it was about an hour long. Anybody remember. This program?