Blanket treatment of the whole herd is rarely necessary and exposing the entire worm population on a property to drench treatment at the same time will ultimately lead to widespread drench resistance.
However, in locations where worms are a common cause of disease or production loss, an annual control strategy with a program of treatments should be implemented to treat the classes of animals which are most susceptible to worms (weaners, first and second calvers and bulls, see the section on which animals are susceptible to worms?). These strategic programs are designed to remove adult worms from animals before seasonal conditions favour worm egg development. They reduce worm egg contamination of pastures.
The ParaBoss annual program pages identify the worms of economic significance and describe the program of treatments and interventions for each Australian climatic and geographical region. The recommendations for each region are generic and therefore need to be customised to the needs of individual producers and delivered by those with knowledge in the field.