Video - strange behaviour

[Footlights]

Not very nice to watch, but what on earth would make a horse behave like this? Seems like very strange behaviour for a racehorse.

http://www.youtube.com/watch?v=mUnwgF7gIlw&feature=youtube_gdata_player

 

[Tickles]

Strange for any horse.

Looked like pain... or possibly something very wrong with sight/head.

Sad.

 

[Footlights]

Very sad indeed. Poor thing.

 

[CM.]

I would love to know