By: David Ellefson, DVM
Director of Technical Services
Tapeworms and proper timing of equine deworming continue to be popular topics of discussion for horse owners. According to researchers, since 1980 there has been increasing evidence definitely linking equine tapeworm (Anoplocephala perfoliata) infestations with many types of colic in the horse. 1 Equine tapeworms have a complex life cycle, which means more than one host is needed for the cycle to be complete. In the case of A. perfoliata, the cycle involves both a horse and an orbatid mite, also known as the grain mite. The horse passes eggs in its fecal material. A mite consumes the eggs and they hatch, releasing immature forms, which invade the mite’s body cavity and form cysts called cysticercoids. A horse consumes the mite as a consequence of grazing or eating hay containing the mite and digests the mite. The immature tapeworms are released from the cysticercoids, which migrate to a specific area of the horse’s gut called the ileocecal junction, where they attach and mature to egg-producing adults, which takes 1 or 2 months.
So what is the BEST method for controlling tapeworms in horses?
Experts agree that the most complete control of equine tapeworms is achieved by a twice-a-year approach: administration of an effective tapeworm anthelmintic (praziquantel in combination with another broad-spectrum anthelmintic, such as ivermectin, e.g. Equimax®) in early spring and again in late fall.
1 Pathological Changes Caused by Anoplocephala perfoliata in the Equine Ileocecal Junction, Veterinary Research Communications, May 2010.
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Equine anthelmintics containing ivermectin or moxidectin have been formulated specifically for use in horses and ponies only.
These products should not be used in other animal species as severe adverse reactions, including fatalities in dogs may result.