One management practice is to never feed horses on the ground. Management involves interrupting the parasite's life cycle. Manure is the primary means through which parasites are spread. Harrowing or dragging pastures during hot, dry conditions will reduce exposure to parasites. Manure should be applied to cropland or composted before being spread on currently grazed pastures.
Chemical control deworming programs work best if treatments coincide with the parasite life cycle.
Most vets suggest that horses be dewormed at least 4 times per year. This would include deworming for strongyles, ascarids, and pinworms four times a year with a dewormer that contains a botacide in early spring and late fall. A common program is to deworm with avermectin every 8 weeks or with other dewormers every 4 weeks during the September through March period. Finally, consult your veterinarian when setting up your horse parasite control program.