Wyoming State Tribune, March 28, 1918. Muleless Days?

The big news was on the war, of course, but a frightening item about a shortage of mules appeared on the front cover as well.

At that time, that was no minor matter.  Mules and horses remained the prime movers of short hauling and agriculture in the United States in 1918.  And the US was also a major supplier of both to the Allies.

Unlike automobiles, a demand for equines couldn't simply be supplied overnight.  A natural product had to develop naturally.  By this point in 1918 horses and mules that were born in the first year of the war were just getting to the point where they were trainable.  Horses and mules of older age, and usable for anything, had been pressed into the demand long ago.