As the British Army mushroomed in numbers, more horses and mules were needed. The Remount Service, having scoured [Britain], started to look overseas for new “recruits” and replacements for those that had been lost, or were no longer fit to return to duty.
North America was the most obvious place to look. With its vast plains and intensive farming, the rolling lands of the West had produced a light draught horse that was a breed apart from its European ancestors—and, importantly, there were plenty of them.
U.S. and (to a much lesser extent) Canadian horses and mules eventually made up two-thirds of those used by the British Army. The supply was constant over the war years, which left many wondering how America came to have so many horses available.
Remount Service purchasers (all of whom had to have a good deal of equine experience so as not to be conned into buying “duds”) traveled throughout the West and Midwest buying thousands and thousands of animals.
At first sight, the “Yankees”, as they were affectionately known, were in a rough and ready shape: they were shoeless, long-haired, tousle-maned and had ragged hips. But they were tough; generations of their kind had become completely at home with roaming out in the open and in all kinds of weather.
Simon Rees, writing in 2009
The British alone lost more than a quarter-million horses during The Great War. The British casualty ratio for horses was approximately 25 per cent.
The single largest cause of death for horses of the British Army on The Western Front: they were worked to death.
The second largest cause of death for horses of the British Army on The Western Front: starvation.
The third largest cause of death for horses of the British Army on The Western Front: pneumonia.
In last place: “killed in enemy action”.
Heaving about in the filthy mud of the road was an unfortunate mule with both of his forelegs shot away. The poor brute, suffering God knows what untold agonies and terrors, was trying desperately to get to its feet, which weren't there. Writhing and heaving, tossing its head about in its wild attempts, not knowing that it no longer had any front legs.
I had my revolver with me, but couldn't get near the animal, which lashed out at us with its hind legs and tossed its head unceasingly. Jerry's shells were arriving pretty fast; we made some desperate attempts to get to the mule so that I could put a bullet behind its ear into the brain, but to no avail.
By lingering there, trying to put the creature out of its pain, I was risking not only my life but also my companions'. The shelling got more intense—perhaps, we hoped, one would hit the poor thing and put it out of its misery.
Lieutenant R. G. Dixon, The Royal Garrison Artillery, 14th Battery, writing in 1915