Get one of the Himalayan Rock salt thingies. My little one lasted about 18 months. Not as enticing perhaps but Likits look like the horse equivalent to Haribo to me - poor Gov doesn't get any fun.
Though perhaps don't if you happen to be feeding Blue Chip (or maybe Blue Chip Dynamic) as i've heard of horses eating the whole rock of salt off the rope and drinking gallons of water to 'self-detox'.
If I hang it where he can jam it up against the bars and crunch on it, 30 mins. If I hang it in open space, 4 weeks and counting. He has not touched it after the 2nd day now that he knows he cannot crunch it.