It would be like here on earth, it depends on what is being hauled, the design of the wagon, and if they are using a relatively modern horse collar harness or the more primitive throat girth harness. You might want to think about the general level of the technology of the culture that made the wagon trail. Also, again depending on the specific situation, Oxen might be used instead of horses. (Stronger, less expensive, less delicate)
Is this fictional culture analogous to the 18th & 19th century Western nations? Then a horse collar and possibly the use of oxen need to be considered. If the fictional culture base predates Western civilization's period of expansion, then something else needs to be considered. This is key technology in such a culture, in many ways it helps define and shape the culture.
Also don't forget Wagon design. A buckboard type wagon, will leave a different trail than a Conestoga wagon, but if the trail is old enough both would have contributed to the trail.
http://en.wikipedia.org/wiki/Horse_collar
Then again, being on a different planet, it can be whatever your story needs it to be. So long as it is logically consistent.
Edit: Oxen would need different harness than horses
http://www.prairieoxdrovers.com/collars.html