Misconceptions About Worming Horses

Worms and other parasites have evolved for millions of years, but there are some steps we can take to subvert their evolutionary efficiency and successfully deworm horses. It’s important to take these deworming steps because parasites increase feed costs, and cause colic and poor performance.

Deworm every 6-8 weeks, including during the winter. Worms do not die because it’s cold. Horses continue to pick up parasites all year.
Rotate wormers. This does not mean rotating brand names; it means rotating products, using a product of a different chemical nature every other time or every second time the horse is wormed. For example, it is not effective to rotate Eqvalan and Ivercare because both are ivermectin. It is effective to rotate Strongid with Eqvalan or Ivercare.
Medicate for bots in the fall and spring. Strongid (pyrantel), Safe-Gard and Panacur (fenbendazole) and Equipar and Anthelcide EQ (oxibendazole) do not kill bots, but Ivermectin-containing products kill bots.
Use the right medication dose. Under-dosing wipes out weak worms, but not strong worms reproduce all the more.
Treat for tapeworms when necessary. Discuss with your veterinarian whether you should use Strongid-P at twice the dose two times a year to kill tapeworms. At the normal dose, Strongid-P controls roundworms, redworms and pinworms.
These 3 dewormers kill tapeworms: Equimax (ivermectin and praziquantel), ComboCare gel (moxidectin and praziquantel), and Zimecterin Gold Paste (ivermectin and praziquantel).
Understand what “All In One” means when it is on the label of a product. Worm products labeled “All In One” do not provide protection against anything but worms. They don’t help horses with tetanus, or flu, or West Nile Virus. Only worms.
Don’t get overconfident with daily wormers. Deworming products added to the feed daily have resulted in worm resistance. To confirm a daily product, such as Strongid-C, is working, have your veterinarian periodically check the horse manure for worms.