The transport use of horses remained vital. They pulled the guns: six each harnessed to the guns on which gunners like Percy trained.
If you look carefully at this snap from Guelph, where the 55th Battery was training, you can see the three pairs of horses, one rider per pair, for the gun in the foreground. The arrangement is somewhat obscured by a single mounted rider — the “outrider” — almost nose to equine nose with the horse closest to the gun and the camera.
And of course, transport for ammunition and other supplies was horse-drawn.
The photograph is from Percy’s small album.