I started putting the IGR in 20% cattle cubes and also put the mineral in them too.  In fact, I use the cubes to "deliver" their 4 oz. of mineral per day, the IGR, vitamins, iodine (for foot rot) and Rumensin.  Each animal will eat the complete pile of cubes each day and it has proven to be a fabulous method of supplementing them while on pasture.  As a side benefit.....   I can also lead them wherever I desire!!

I have used cubes for delivering wormer and it is a good method.  Because the wormer has a short shelf life I prefer to pour them in the chute, but the point is that cubes are also a good method to worm cattle.