Alpine has loaded into both step up's and ramps, but he prefers the ramps. I don't know what his initial training was, but I watch all the horses in step up's "feel" for the step. Alpine gets very nervous if he doesn't know where his feet are and where they are going. If I am backing him out of a step of trailer, he gets nervous and tends to lunge backwards to get out faster. On the ramp, he'll just back quietly down. For him, the ramp is a safer option because I don't have to deal with the nerves. I have never seen him slip on the ramp, nor has uneven terrain been a problem. The trailer I use is a 87 or 88 model 3 horse stock type slant in great shape. I couldn't ask for much better to haul with...