The backlighting gives the mane such a nice glow. Good exposure here. The right side of the frame really doesn't contribute much to the image so a square crop or even shooting this vertical would have helped... I might of opened my lens up here to soften the BG this is where a lens such as the 300mm F2.8 would really shine....
Here is a new crop
I agree with your comments about a better lens but I am afraid I could not do much about the lens back then as I had no money. I now have a 500mm which is pretty good.
If only the bg would have been nice. I would have loved to shoot it at f3.5, if not f2.8. The present format would have worked, if the background would have been clean. Due to the bg, a vertical/square format would work better as it would eliminate the right side bg.