If there is an art to getting horses to load in a trailer, then this it.
The first thing that must happen is communication between the horse and his handler. The horse must understand what is required of him and the handler must make it easy to understand.
Thus, you must start by getting the horse to move forward in either direction. After a direction is established then get him moving in the opposite direction. A round pen is excellent for this purpose.
When the horse gets good at moving both directions then it's time to hook a lead rope to his halter and lunge him left and right. For instance, when you point left, the horse must know to go to your left. And vice versa for going right.
The final result should look like this. You're holding the lead rope while facing your horse. As you hold the lead rope in your right hand, you hook the middle of the lead rope with your left thumb. Lift it up and point to the left.
Your horse, now knowing what to do, immediately goes to your left. After a circle or two you switch hands and get the horse to go to your right.
When he gets good at that, then send (lunge) him through gate openings, barn door openings, etc. Also, lunge him in smaller spaces to help him deal with his natural claustrophobia. You can do this by lunging him between you and a fence. As he goes back and forth make the space between you and the fence smaller. Be careful not to get stepped on.
Now that he's good at that, you take him by the trailer. You open the door and let him sniff it. Then you step back and face your horse. You lunge him left and right in front of the trailer while he passes back and forth by the opening.
After all this pointing and sending your horse now knows what you want. You have communicated to him when you point left that he is to move left and so on.
The next step is to face him to the trailer. With his head facing into the trailer and you standing on his left side you then send (point) him into the trailer.
Some horses will simply jump right in the trailer where others may take more work.
If your horse doesn't go in after pointing and coaxing then take him away from the trailer and make him work. Now you want to convey the idea that being in the trailer means he can relax. Being outside the trailer means he has to work hard. Eventually, he'll catch on.
Once you have him in the trailer, pet him and let him relax. Talk to him. Let him know how good he did.
Obviously, getting a horse to load in a trailer isn't rocket science. But you can do it. It takes patience and work
Andy Curry is a nationally known horse trainer and author of several best selling horse training and horse care books. For information visit his website at www.horsetrainingandtips.com. He is also the leading expert on Jesse Beery's horse training methods which can be seen at www.horsetrainingandtips.com/Jesse_Beerya.htm.