Seems that the organizers are staging the concert, which is supposed to draw more than 100,000 people, right next to a racecourse. And they want to dope up the 300 horses on tranqs so they don't freak out during "When the Whip Comes Down."
The Reuters story said, "The sedative would be diazepam. In Serbia it trades under the name Bensedin, a very popular drug during the 78 days of NATO air strikes in 1999, when much of Belgrade's adult population was on tranquilizers."
OK, sing it with me. "Wiiiild Horses, couldn't drag me awayyyy." And especially if they were tranquilized on Bensedin!