On Leroy Troy's album, THE OLD GREY MARE is attributed to Carson Robison. However, I can't find any evidence that Carson Robison recorded it.

The Online 78 rpm Discographical Project lists recordings called

(THE) OLD GRAY/GREY MARE, by
Arthur Collins and Byron Harlan, 1917.
Earl Fuller's Famous Jazz Band, 1917.
Prince's Band, 1917.
University Quartet, around 1917.
Carl Fenton & His Orch, 1925.
Land Norris (banjo), 1926.
Al Bernard, around 1927.
Gid Tanner's Skillet Lickers, 1927.
Vernon Dalhart, 1927 (attrib J Warner) & '28 (attrib Frank Panella)
Lew Childre, 1930.
Gene Autry, 1936.
Milton Brown & His Brownies, 1936.
Freddie Fisher & His Orch, 1941.
Bob Gregory and his Cactus Cowboys, date unknown.

and other songs called:

OLD GREY MARE KICKING OUT OF THE WILDERNESS by Earl Johnson & His Clodhoppers, 1927.

TIM KELLYS OLD GREY MARE by Jack Murphy, 1927.

OUR OLD GREY MARE by Johnny Marvin, 1932

HARNESS THE OLD GREY MARE by Gillis Serenaders, 1934.