What Happened to the Horses?

[Morthoron]

Originally Posted by Peregrin Took

Upon watching The Return of the King with my friends tonight, we noticed something we never did prior. Before the Battle of the Black Gate, when Aragorn gives his speech to his men, they are all on horses. Then, once they all charge for battle, their horses are gone!

It took us years to notice it, so it's not a big deal. However, it's pretty interesting nonetheless. Has anybody else noticed this?

Not only do the horses disappear at the Black Gate, but the Elves completely disappear after the Battle of Helms Deep! Chalk them up to stellar editing, Peregrin.