I too found the BIG shavings do not create as much
dust, but another option is the wood "pellets" to put on the floor. No dust,
work the same, or better than some shavings. Or, a bit of kitty litter
might give the traction you are looking for. Something to consider is, if this
horse slips while getting in the trailer, he may not have secure footing as you
go down the road either. I can not imagine how tense a horse could get if he
kept sliding around in a trailer because he did not have traction. Something
that is SO easy for you to fix with the right bedding on the floor. And
personally, I WANT my horse to pee in the trailer if he feels the need to do so.
When he holds it, it makes him grumpy, and uptight. And, I don't think it
is the most healthy thing he could be doing.