horse swishing its tail running in the race

Question
hello sir. while watching a race yesterday. i observed a horse constantly swishing its tail from starting point to finish line. it finished unplaced. isnt the horse interested to run? was it feeling uncomfortable? can you please explain me?

Answer
hi  yes there must have been someting that bothered that horse during the race. could have been the position of the saddle or it did not like the jockeys way of riding. a horse will sometimes switch it's tail when being hit with the whip, they do not like to be hit while racing. thanks ED HESS