"Old Dog Blue" (also known as "Old Blue") is an old folk song, believed to have originated from the minstrel shows of the late 19th century. A 1928 version by Jim Jackson, entitled "Old Dog Blue", it is included in the Anthology of American Folk Music.
It has been recorded by Joan Baez, The Byrds, Furry Lewis, Guy Carawan, Ramblin' Jack Elliott, Cisco Houston, The Dillards, Bob Gibson and Bob Camp, Sam Hinton, Pete Seeger, Dave Van Ronk, Ian & Sylvia and many others.
It was printed in The Joan Baez Songbook, Alan Lomax's The Folk Songs of North America and The Burl Ives Songbook.
I think I first learned it from Burl Ives.