You can load more horses into a slant load trailer than the same sized straight load trailer. There is generally more storage space for equipment, tack, and dressing rooms in slant load trailers, and your horses can turn around inside the trailer and walk out head first.  A straight load trailer (also called a walk-through trailer) is usually taller and has more of an open-concept feel inside than its slant load counterpart. This can be more comfortable for horses with claustrophobia. Some straight load trailers come with a walk-out door so you can unload one horse without removing all of them. It is also usually easier for horses to balance when the trailer is moving because in slant load trailers they have to rely on dividers to keep their balance.