I find it fantastic that you managed to capture this scene in a way that when the viewer looks at it, it feels as though we're right there beside you. That's pretty cool, if you ask me!
I think it was a good choice to turn this into a B&W, because first of all you don't see too many scenes like this in B&W, and second because I've always found that when a photo is in B&W, it makes the viewer really look into rather than being distracted by all the colors and whatnot.
I also like the timing, and how you captured the white horse looking on while the other one is eating something along the side. There really aren't any awkward poses, which is great.
The focus could be a little sharper, perhaps, so that we can see even more detail in this photo. Otherwise, it looks great!