The use of horses in World War I marked a transitional period in the evolution of armed conflict.
Cavalry units were initially considered essential offensive elements of a military force, but over the course of the war, the vulnerability of horses to modern machine gun and artillery fire reduced their utility on the battlefield.
This paralleled the development of tanks, which would ultimately replace cavalry in shock tactics.
While the perceived value of the horse in war changed dramatically, horses still played a significant role throughout the war.
All of the major combatants in World War I (1914–1918) began the conflict with cavalry forces.
Germany stopped using them on the Western Front soon after the war began, but continued limited use on the Eastern Front well into the war.
The Ottoman Empire used cavalry extensively during the war.
On the Allied side, the United Kingdom used mounted infantry and cavalry charges throughout the war, but the United States used cavalry for only a short time.
Although not particularly successful on the Western Front,
Allied cavalry did have some success in the Middle Eastern theatre, against a weaker and less technologically advanced enemy.
Russia used cavalry forces on the Eastern Front, but with limited success.
The military mainly used horses for logistical support; they were better than mechanized vehicles at traveling through deep mud and over rough terrain.
Horses were used for reconnaissance and for carrying messengers, as well as pulling artillery, ambulances, and supply wagons.
The presence of horses often increased morale among the soldiers at the front, but the animals contributed to disease and poor sanitation in camps, caused by their manure and carcasses.
The value of horses, and the increasing difficulty of replacing them, was such that by 1917 some troops were told that the loss of a horse was of greater tactical concern than the loss of a human soldier.
Ultimately, the blockade of Germany prevented the Central Powers from importing horses to replace those lost, which contributed to Germany's defeat. By the end of the war, even the well-supplied U.S.
Army was short of horses.
Conditions were severe for horses at the front; they were killed by artillery fire, suffered from skin disorders, and were injured by poison gas.
Hundreds of thousands of horses died, and many more were treated at veterinary hospitals and sent back to the front.
Procuring fodder was a major issue, and Germany lost many horses to starvation.
Several memorials have been erected to commemorate the horses that died.
Artists, including Alfred Munnings, extensively documented the work of horses in the war, and horses were featured in war poetry.
Novels, plays and documentaries have also featured the horses of World War I.