Definition of "doughboy"

The "dough boys" were loaded into army wagons drawn by mules, and with the cavalry at the flanks the relief column started.

1901 July 19, “Horses in time of War”, in The Agricultural Journal and Mining Record‎, volume 4, number 10, page 296

The miser, a-seeking lost gelt, / The doughboy, awaiting the battle, / May possibly know how I felt / While the long years dragged by as the dealer / As slow as the slowest of dubs, / Stuck out the last helping of tickets / 'Till I lifted—the Bullet of Clubs!

1969, Robert L. Vann, The Competitor, volumes 2-3, page 135