I like the framing of the bison's face with the frosted grass - nice contrast from the bright white to the dark bison. Plus you can see the whole eye - that's good. I would have preferred not to see the horn cut off.
The eye is a strong visual center of interest... I would have liked to see the entire horn of the bison. I think if you would have included a bit of the shoulder the head coming into the frame would have felt more natural....