I highly disagree with the method of leaving the horse's food in the trailer. Not only it is possible that some horses will be so scared to go in the trailer that they WON'T eat, but even if they do go in the trailer, they are going in because they wanted to -- not because you have asked them to load. It teaches them nothing.
I have Clinton Anderson's trailer loading DVD as well. Love it because he explains things so well!
I've never not had a horse load using his method. And if you say YOU are getting tired, it suggests to me that you aren't doing something right. You shouldn't be getting tired because your feet should not be moving -- the horse's feet should be moving, but not yours.
Every time you do a session with him, how long does it last? You shouldn't be working on this more than 10 to 15 minutes a day.
Are you trying to get him all the way on the trailer each time? You shouldn't be. You need to start in baby steps.
Can you disengage your horse's hindquarters simply by glaring at them with your body language? If not, you need to get him more responsive to your ground work FIRST before you try to put the trailer into the equation.
Can you lunge the horse both ways, and easily make frequent direction changes? If not, get that working first.
Can you get your horse to back up simply by jiggling the leadrope? If not, you guessed it, work on that first.
Once you have that mastered, then we can try to do some work around the trailer. Can you work by the open trailer door, and just SEND HIM back and forth between you and the trailer? Do not ask him to load. Just ask him to move his feet as you ask, with the trailer "just happening" to be nearby.
You can also stand at the open trailer door, and ask your horse to lunge from one side of the trailer, to the other, around the back (like in a half circle). Again, you aren't asking him to go on the trailer, you are just simply asking him to lunge with the trailer "just happening" to be nearby.
Any time your horse wants to stop and sniff or investgate the trailer, LET HIM. It is a good thing for him to be curious about the trailer.
When you finally get to the point where you can ask him to load PARTIALLY, you are only going to do one foot at a time. Once he gets a foot in the trailer, change your mind. Ask him to back off. Then change your mind. Ask him to put a foot in again. THen change your mind, Ask him to back off. This is the "pressure and retreat" method. Eventually, your horse will WANT to put that one foot on the trailer because you are making no big deal of it.
Again, make your sessions no longer than 10-15 minutes and never make it your goal to get him ON the trailer, until you are actually ready.
When you can load one foot, you will eventually ask for 2 feet in the trailer, then ask him to back off. Two feet on, then back off. Repeat, repeat, repeat.
Or maybe he'll have a bad day. Horses have bad days too. If you need to regress to going with one 1 foot on the trailer, that's okay! Just make it a positive lesson with what you can work with.
Always make sure he is square to the trailer. If his hips go crooked, that's where you are going to use your earlier skills to "glare" at the offending hindquarters, ask him to move it, and straighten out. That's why you can't skip the beginning ground work steps -- you need to be able to control his body.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.