A slant load is a type of horse trailer or horsebox in which the horses travel at an angle to the direction of travel — typically at 45 degrees — rather than straight ahead (straight load) or sideways (side load). The slant load configuration allows more horses to be transported in a given trailer length, and many horses prefer it because the angled position aligns naturally with how they balance during movement. Slant load trailers are particularly prevalent in North America, where they dominate the leisure and competition trailer market.
How Slant Loading Works
In a slant load trailer, dividers are positioned diagonally across the width of the trailer, creating individual stalls in which each horse stands at approximately 45 degrees to the direction of travel. The head typically points toward the front nearside, and the horse’s hindquarters are angled toward the offside rear. Each stall has a divider to the left and right, and a chest bar or door at the front to prevent the horse from stepping forward into the next space.
The number of horses that can be transported in a slant load trailer depends on the length of the trailer and the size of the horses. A three-horse slant load trailer may be no longer overall than a two-horse straight load, because the diagonal positioning allows each stall to be shorter (measured along the trailer’s length) while still accommodating the full body length of the horse at an angle.
Slant Load vs Straight Load
The debate between slant and straight load configurations has been ongoing for decades. The central question is which orientation is most comfortable and least stressful for the horse during transit.
Proponents of slant loading argue that horses naturally angle themselves when travelling in a straight load — pointing their bodies toward a diagonal that gives them better balance — and that slant loading simply formalises this preference. Some research supports the idea that horses in slant load trailers show lower stress indicators during transit.
Proponents of straight loading counter that a straight load gives the horse more room to balance front-to-back by spreading its legs, and that good-quality straight load trailers with removable dividers allow horses to travel loose — the optimal configuration for reducing physical stress. The BEVA has published guidance noting that horses travelling loose or at liberty in a trailer show the lowest stress and musculoskeletal load.
Practical Considerations
Slant load trailers are more complex to load and unload. Horses typically load in a specific order and must unload in reverse order — a horse at the front of a three-horse slant cannot be unloaded without first unloading the horse behind it. This can be inconvenient at busy showgrounds or when horses need to come off at different times.
The arrangement also means that the horses are unloaded rearward — they must back out — rather than walking forward through a front ramp as in some straight load designs. Some horses find reversing out of a trailer significantly more stressful than walking forward. Proper loading training should include practising reversing from the trailer calmly. Good management of loading anxiety is particularly relevant for horses used in slant load trailers where the unloading process is less intuitive for the horse.
Towing Requirements and Weight
Multi-horse slant load trailers are typically heavier than equivalent straight load trailers due to additional dividers and structure. Always verify that your towing vehicle’s maximum authorised towing weight exceeds the loaded trailer weight with all horses aboard, with a safety margin. In the UK, trailer towing regulations require a Category B licence with the correct entitlements depending on trailer weight — check current DVLA guidance if in doubt.
Frequently Asked Questions
Are slant load trailers better for horses?
The evidence is mixed. Some horses do prefer the angled position, and the configuration suits some trailer-to-horse size combinations very well. However, a well-maintained straight load trailer with a loose or open divider arrangement may be equally or more comfortable. The individual horse’s preferences and loading behaviour are the most practical guide.
Can large horses use slant load trailers?
It depends on the trailer’s specifications. Larger horses — 16.2hh and above — may find standard slant stalls too short for comfortable travel at angle. Always measure your horse’s body length and compare it against the stall diagonal measurement in the trailer specification before purchase.
How do I introduce my horse to a slant load trailer?
Use the same patient, progressive approach as for any trailer loading. Start with the trailer stationary and allow the horse to investigate. Reward calm forward movement toward and into the trailer. Build positive associations through short journeys before attempting longer hauls. Horses that have had negative loading experiences benefit most from a gradual retraining approach with no time pressure.