Light Shed on Loading Horses in Trailers
Light levels make a difference with how comfortable horses are at entering a horse trailer.
A study at University of Queensland in Australia tested whether bright or dim lighting stress horses more when loading into a horse trailer.
The horses tested were all yearlings who were trained for the study, with positive rewards of hay and neck scratching, to enter a horse trailer voluntarily. The horses walked up a ramp to get into the partially-enclosed trailer.
Researchers found that whether horses were leaving a well-lit or darkened arena into a lit or dark trailer made no difference to their heart rate or other signs of fear. In all lighting situations, the heart monitors worn by the horses showed an average heart rate increase of 50 beats per minute. This indicates the yearlings always felt somewhat fearful about entering the trailer.
In certain light conditions, though, the horses revealed through their behavior that they found the situation stressful. When loading from a brightly-lit arena into a dimly-lit trailer, the young horses were obviously more wary about making the transition. Under these lighting conditions, the horses lowered their heads and sniffed the ground noticeably more, and were more likely to turn away from the loading ramp.
Those behaviors did not occur nearly as often when horses left a dark arena to enter a dark or lighted trailer. The study's findings suggest that horses experience the greatest unease when leaving a bright environment to enter a dark horse trailer.
Nicola Cross, Fraukje van Doorn, Caroline Versnel, Judy Cawdell-Smith and Clive Phillips. 2008. Effects of lighting conditions on the welfare of horses being loaded for transportation. Journal of Veterinary Behavior. 3(1): 20-24.