Horses in the First World War Written by Pam Preedy. We sometimes forget that horses were essential to the Army during World War One. Much attention has been focused on the dreadful conditions and sufferings of the men in the trenches, yet the suffering was shared by the horses as seen in the book, play and film War Horse by Michael Morpurgo. All the armies used horses and mules. At the outbreak of war, there were 25,000 horses at the disposal of the British Army. Under the Horse Mobilisation Scheme of…