Tips for delaying drench resistance on your farm

• Find out the resistance status on your farm and monitor the efficacy of drenches used regularly – the use of poorly effective drenches will allow a large number of resistant worms to survive.
• Feed your stock well – quality and quantity.
• Monitor egg counts and stock condition.
• Use cross-grazing with alternate species or adult animals to lower pasture worm burdens for young stock.
• Support development of immunity in older stock through genetic selection and nutrition.
• Use grazing of hay/silage regrowth, new pasture, forage crops and spelling pasture to reduce exposure of vulnerable stock to worms.
• Consider drenching strategically to maintain a good ratio of susceptible to resistant parasites, e.g. – don’t drench adult stock unless it can be justified, or – don’t drench the heaviest/best-conditioned lambs.
• If resistance has not yet developed, use combination drenches to further delay its onset.
• Use low-volume products for young animals or animals yarded for a prolonged period.
• Check drench guns are calibrated and functioning properly.
• Don’t under-dose. Adjust drench volume to the heaviest animal in the mob.
• Use good drenching technique – gun nozzle applied gently over the back of the tongue.
• Do not depend on rotating between drench action families to combat resistance – it is ineffective. Use of combination drenches is a better option.
• Use quarantine drenching for bought-in animals. Assume that all bought-in stock are carrying resistant worms.
• Do not put animals on to “clean” pasture after their quarantine period.
• Think about reproductive advantage and refugia.
• Have a farm-specific, flexible parasite management plan.

Smart Drenching is using the right drench for your stock. No more. No less.