Many versions. Perrow collected this one in 1906 from Tennessee whites.

Lyr. Add: The Old Gray Mare (Perrow)

Ole Turkey-Buzzard come a-flyin' a-by, (3X)
Says, "Ole man, yore mare's gon die."

Ef she dies, I'll tan her skin; (3x)
Ef she don't, by doggies!(1) I'll ride 'r agin'.

She got so pore I couldn't ride; (3X)
Bones stuck up right thoo her hide.

Then I hooked 'r to the plough; (3X)
Swore by doggies! she didn't know how.

Then I skinned some pop-paw(2) lines; (3X)
Swore by doggies! she'd take her time.

Then I turned her daown the creek; (3X)
For her to hunt some grass to eat.

Then I follerd daown the track; (3X)
Found 'r in a mudhole flat uv 'r back.

Then I felt so devlish stout, (3X)
Grabbed her by the tail en' puller 'r out.

Then I thought it weren't no sin; (3x)
Took out my knife en' begun to skin.

Refrain
Yankty doodle dum, yankty dee,(3)
Yankty doodle dum, yankty dee.

With music. (1) a common expression in East Tennessee. (2) paw-paw tree. (3) Imitation of the sound of a banjo-string.
Collected from East Tennessee mountain whites; 1906.
E. C. Perrow, 1911, "Songs and Rhymes from the South," II. Songs in which animals figure, 1., JAFL, vol. 25, pp. 137-155. On line, www.immortalia.com

A related song from whites; "I Had a Little Mule and His Name Was Jack."