Short film about family in the wild

I saw this short film in the 1970’s or early 80’s before the feature film was shown. It was about a family living in the wilderness and something happened to the daughter and she became mute. When her brother is about to be attacked by a mountain lion/cougar she regains her voice to warn him. It had that Disney/The Waltons type feel – set in the American mountains I think. There was snow in the scenes I remember. Have searched for the title but as it wasn’t the main movie shown it’s eluding me!