I only guessed that one would be dealing with the rear end of the horse because you mentioned horse poop, or as we once called it "road apples".
When I was 11, my father and I went up Pike's Peak on burros. It was a great experience. Along the way we met a lost member of some revival group, and passed though a place where there had been a fire in the 1890's, called the "Dismal Forest", because all the trees were dead, and of course gnarly and twisted like the scary trees in a Disney toon. My father and his father climbed it on foot when my father was 12 and his father was 42, but my father was 52 and decided on the burro trip. There were no burro trips when my father climbed Pike's Peak.
One remarkable thing was I did not realize how much a burro poops. The burros were in single file, and when not looking at scary trees, it was hard to miss the burro in front of me, which lifted its tail and pooped about every 30 minutes. Plop, plop.