I hate to say this...but the framing, almost an industrial type of framing, does not fit the lovely mood.
I really like the rollling hills of green grass and the grey sky balanced so nicely by the color of the horse...but oh gee...the horse seems to have to many green tones (mane, tail...body). Maybe over-saturated? Maybe my monitor?
I hope you don`t mind my honesty. Composition and mood is wonderful.