In further times people were very dependent from the weather, which often destroyed sawing and crop. Especially the people in the mountains prayed for a settled weather.
In their misery this people used old rituals of their forefathers to get heard from the gods of fruitfulness and growth. Notably in the winter they wanted to achieve an increase of the daytime instead of the long night time.
For exorcising demonical powers they also needed demonical masks => PERCHTEN
Because of this the tradition of Perchten is a monument of an old religion, which roots are reaching back until the Stone Age.
The drub with the horse tail drives away all the evil and gives you luck and health.