Which Deworming Method is Most Cost-Effective?

One topic horse owners have heard a lot about in the past few years is anthelmintic resistance. And while many veterinarians encourage their clients to change to fecal egg count (FEC) directed deworming from rotational deworming—something many have practiced for years or decades—some are slow to adapt. But new study results from Scotland suggest that FEC-based deworming could have added benefits to horse owners: Researchers believe FEC-directed programs will not only help preserve current dewormers' efficacy, but could also save horse owners money in the long run.

“Not all horses need deworming,” relayed Hannah Lester, BSc, MSc, MVPH, a student at the Moredun Research Institute, in Edinburgh, Scotland, and lead researcher in the study. “The majority of horses will have a low or negative FEC, and we typically see that 80% of the high FECs are in 20% of horses." This means only about 20% need aggressive deworming treatments, she said.

To find out which method is most cost-effective, the team compared the annual costs of an FEC-directed deworming program used on 368 horses at 16 equine facilities with the projected costs of an interval deworming program (reportedly used by the majority of questionnaire respondents in a previous study) for the same number of horses.

The team based the cost of the FEC-directed program on the total price of:

  • Three FEC tests performed by a commercial online retailer for each horse (one in the spring, summer, and fall);
  • The administration of pyrantel embonate (called pyrantel pamoate in the United States) in spring and summer and ivermectin in fall to horses with an FEC of 200 eggs per gram or more;
  • A follow-up FEC 14 days post-treatment to determine treatment efficacy; and
  • Treatment with moxidectin/praziquantel in December with no FEC test for all horses.

The team based the cost of the interval deworming program on the price of two moxidectin treatments per year and two moxidectin/praziquantel treatments per year, with the price of treatments based on the U.K.'s average retail prices.

Upon reviewing the results, the team found that overall costs of the FEC-directed program at each of the 16 facilities were considerably less, farm-wide, than the projected costs of an interval program, with savings of several hundred dollars over the course of a year in most cases.

“There are no new anthelmintics likely to be licensed for use in horses in the short- to medium-term, so we must implement deworming programs to protect the efficacy of the drugs that are still working, particularly moxidectin, which is the only drug that is still effective against encysted small strongyles,” Lester concluded.

The study, “A cost comparison of faecal egg count-directed anthelmintic delivery versus interval program treatments in horses,” will appear in an upcoming issue of the Veterinary Record

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.