I have a mare who constantly paws in the trailer and I'm looking for suggestions to make her do it less/not at all. I've only had her for about 3 months, and have only been hauling her for 2. She still paws with hay, alfalfa, and feed. She's a nervous horse in general (I think she was abused before I got her). I'd rather not hobble, but will if there is no other way to stop it. 

Ace? I put mine of Redmond Daily. It made a BIG difference in nervous behaviors. 

You could try using pawing chains, same thing as kick chains that you put around the hock area to teach a horse to stop kicking in the trailer. Are pawing Bracelet's. . You can make Pawing Bracelets out of horse shoes that work pretty good for pawing horses. 

I have one that paws too and its VERY annoying. I will be watching this thread. The only thing I have found to stop her from doing this is a big day on the mountain checking cows.  On the ride home there is silence in the trailer.

There are trailer hobbles that go over their back and a fleece lined strap that goes around both front legs just above the knees. You buckle that up after you get them loaded and they can still move and have stability, but they can't get the lift and forward motion to paw much. I have a friend that has a pair for a horse she used to have. They seemed to work really well.

Her's were made by Equine Supply - the lady that owned that passed away, but I think someone else has taken over the business. It is out of Utah. I've never seen them anywhere else.

There are better products to use than ace. Don't go there with the ace. Oxygen products make Relax which is a paste or a pellet that you put in your feed. It works. 

Thank you for all of the suggestions!!