Daily dewormer may be a way of controlling internal parasites provided two things occur:
1. The parasites must be susceptible to the drug (Pyrantel).
2. The horse must be ingesting the correct dose at one meal and not leaving some of the product in the feed pan or sharing the dose with another horse.
To determine if the daily dewormer is working on your farm, a fecal sample should be evaluated on your horses or on a representative sample of your horses.
Pyrantel is not effective against bots. Ivermectin or moxidectin (Quest) must be used in the fall after a heavy frost to control bots. Also, even if the pyrantel appears to be effective, the manufacturers recommend that you purge deworm two times per year.
