Please read all of the other thread including the links. There seems to be quite a bit of info located such as this:

Title: Horsey keep your tail up keep the sun out of my eyes.
First Line: Reuben is so silly, he will never wear a hat
Chorus: Oh horsey, keep your tail up
Music by: Hirsch, Walter, Kaplan.
Words by:
P/P/D: S.I. : M. Witmark, & Sons, c1923.
Location: SPC, KIRK PS 1923-1929

Sandy and others have listed some pretty exhaustive info there.

Spaw