You probably didn't know Michael Landon grabbed The Little House on the Prairie theme song from this Bonanza episode
We heard the famous theme song three years earlier on Bonanza.
The biggest fans of Bonanza might recall this episode from the 12th season that actually contains a surprising bit of TV theme song history.
The 1971 Bonanza episode "Top Hand" is about a power struggle the erupts when another rancher's foreman takes a crack at stealing away a major cattle-driving job that the Cartwrights' foreman is already handling. It begins with a large herd of cattle being steered across a river, through a valley, over a plain, and into a pen at the ranch.
In this seemingly unassuming opening scene, the emotional tone of the episode is only really established by a soaring song that plays throughout the scene. Composed by David Rose, this music is instantly recognizable to fans of a different 1970s TV drama.
Over the sound of cows groaning through a crashing whitewater river, this opening scene would become the first time we'd hear what would become the famous theme song of Landon's later series The Little House on the Prairie. (Watch the video at the top of this post to hear the song on Bonanza.)
Of course, Landon carried over many things from Bonanza when he launched his Little House, including a bunch of character actors you'd recognize from both shows. It makes sense then that he would want Rose to score his next show, injecting as much from his Bonanza family as he could into his cherished family drama to great effect.
In the book Michael Landon: The Career and Artistry of a Television Genius, the author notes that Rose occasionally sprinkled other music from Bonanza into Little House on the Prairie, but perhaps nothing stands out so prominently as the "Top Hand" intro scene song that he repurposed as the theme song, three years after we first heard it on TV.
Unsurprisingly, the composer won Emmys for his work on both shows, but it was his music used to underscore the Ingalls girls running (and adorably tripping) down a grassy hill that took on a cult fandom of its own, later parodied on everything from The Jetsons (when they produced new episodes in the 1980s) to Family Guy (several times, but most notably in the 2012 episode "Livin' on a Prayer"), not to mention the seemingly endless references on That '70s Show. It's an unforgettable sequence inextricably carried by Rose's composition.
Now you can trace the roots of that tune back to Bonanza, and the more traditional Western scene that the music was originally composed to score.