A horse trailer or horse van (also called a horse float in Australia and New Zealand or horse box in the British Isles) is used to transport horses. There are many different designs, ranging in size from small units capable of holding two or three horses, able to be pulled by a pickup truck or even a SUV; to gooseneck designs that carry six to eight horses, usually pulled by 1-ton dually-style pickups; to large semi-trailers that can haul a significant number of animals.
The least expensive type of trailer is the stock trailer, a trailer designed for cattle that is enclosed on the bottom, but has slits at approximately the eye level of the animals to allow ventilation. Trailers designed specifically for horses are more elaborate. Because horses are usually hauled for the purpose of competition or work, where they must arrive in peak physical condition, horse trailers are designed for the comfort and safety of the animals. They usually have adjustable vents and windows as well as suspension designed to provide a smooth ride and less stress on the animals.
The first horse trailers were said to be horse-drawn ambulances created by city fire departments to take their wounded but savable horses from the scenes of accidents (which were common) back to the veterinarian at the firehouse.
Highly valued race horses were originally transported by specially outfitted railroad cars, but this transport was difficult to use due to issues of scheduling and delays. In December 1918, Popular Science Monthly reported on a new concept for transporting race horses in specially modified "Motor-Trucks" that eliminated these transport delays.[1]
In World War 1, horses were used with infantry in France, and many were injured in the course of the war. If these animals could be transported back to animal hospitals, many could be saved. For this purpose a special horse ambulance vehicle was developed which could be rotated so that horses could walk forward both onto and off of the ambulance truck.[2]
As horse-drawn transportation gave way to faster, mechanized transportation, there remained a need to transport horses themselves for work, sport, and other purposes. Thus, many types of trucks, vans, and trailers were developed or modified to transport horses on modern highways.