I find the extreme highlights on the pink sweater (esp. the hood) a little distracting, but I love the vertical nature of the composition.
Were you standing up while taking this picture? I know crouching down might have made that third group of cows in the back left (which I love) clutter the image instead of add to it, but I wonder if it might have made the juxtaposition between the brown cow and your niece look more menacing. But then again, that would have been a different shot altogether. I think yours works.