Horse transports are actually an interesting part of history, and people got rather good at transporting horses from place to place. People did so for hundreds and hundreds of years, and horses were valuable commodities.

That said, before I can actually answer your question, I need more specifics. I need to know when, where, and in what context.

A military horse transport differed from a civilian horse transport, and both sorts change rather dramatically over the course of history as boats got better and better.

So please, be specific!