Timing can change the effectiveness of your deworming program tremendously. Administration of drugs to kill grubs given too late in the season can cause damage to your cattle, for example. Additionally, one of the goals of parasite control is to clean up cattle so they are not shedding parasite eggs when they go onto clean pastures or ranges-preventing parasite egg buildup on the pastures. This will decrease future parasite egg buildup in the cattle's environment. Persistence of Drug's Effect.
Some drugs continue to kill parasites for many days to weeks after they are given.
Be sure to check out this aspect of the dewormer. This characteristic of the drug's action can also be helpful in keeping pastures free of parasite eggs. Route of Administration. Pick the method that works the best for you and your cattle. Also, consider the total costs of administration, including the stress of the animals.