I think you are referring to the "SwisskaPolka." If you are, it can be found on the "musical History of Disneyland" 6CD set. It might be on other CD's too, but that's the only collection I have with the song on it.
Yes, that little tune is called the "Swisskapolka" and was written by Buddy Baker for the movie. The organ version from the park is available on the big 6 CD Disneyland box set and was also on the two disc Disneyland 50th CD. The movie soundtrack version isn't commercially available.
Also, the "Swiss Family Robinson" DVD extras feature a clip of the animal race with mus/efx audio only and that tune is used in the score there as well.