if you were 100% resistance and then Diluted the resistant population by 1% by introducing nonresitstant stock,leaving 99% resistance then repeat the process multiple times through grazing rotation and a rotation of non resistant carriers over a period of a time surely you can breed out resistance fluke along with not using the resistant drug and choosing other products to dilute resistance. The only problem I can see that stock known to be 100% non resistant need to be infected with fluke at the time be placed on known resistant pasture thus reinfection occurs but mating with resistant flukes now this stock is carrying resistant flukes and are no longer a viable to use to dilute resistance so fresh nonresistant stock would need to be added. And resistant drug may take years to become even half effective All this with a small chance of diluting resistance if even possible at all! U need to be a scientist to understand it all