My grandpa and my great uncle both used to sing this song but some of the words may have been altered because my grandmother didn't like him to swear. Here are both verses as I remember them. If you find out any more or a published source I would be very interested in knowing where it came from. There are a lot of historical political and racial meanings from what I glean.
^^
Had me horse and I called him Napoleon
All on account of his bony parts.
He was sired by Old Hamiltonian,
Darned by everyone 'round these parts.

Bred so fine you could see right through him,
Hair as fine as any silk,
I'd hitch him up to my old milk wagon
An' if I wanted him to stop, I'd holler "Milk!"

The other day when I was out a-riding,
Along came a man with a rig so neat.
He said, "Look here, you rube.
I'll run you a race right down this street."

So off we started a helter-skelter,
And I had smile all over my face.
Sure as I's sinner, I's comin' in a winner
When a lady called "milk" and I lost the race.

Slept in barn late last Sunday,
Hadn't a penny and I was dead broke.
As I lie there with my mouth wide open,
A gosh darn rat ran down my throat.

So I got me some cheese and an' I put right here (points to chin)
An' I got me a tom cat all full o' fleas.
Up came the rat an' spied the cat
Down went the rat, cat, and whole darn cheese.