De-worming Program & Quantitative Fecal Testing

Protecting Your Horse

Important Notice!

In an effort to address the very serious issue of parasite resistance, please see the De-worming: Rethinking Parasite Control at the bottom of this page. We have adopted some changes to our de-worming protocols. We want to make it clear that we do not want clients to stop de-worming at this time!  We now recommend periodic quantitative fecal testing and customizing a de-worming plan based upon each horse's individual results. Please continue following the current schedule until you begin the new testing program.  Most horses should be tested in the spring and fall before de-worming. 

The strategic de-worming program offered by Equine Veterinary Service is designed to protect horses against specific parasites that were found to be problematic for horses in this area. In order to prevent the parasites from causing damage to the horse, the program targets parasites which develop during certain times of the year.  Please follow these recommendations until your horse has started the new program above. 

When purchasing de-wormers, purchase products that contain the active ingredients (chemical names) listed below. Keep in mind that the individual product names may vary. (The chemical name of the de-wormer will be listed with the brand name in parentheses).

This de-worming program is recommended for horses one (1) year of age or older and in good health. If you have any questions, please contact our office.

Equine De-Worming Program Outline

When To Dose Product (Chemical Name)
January 1: Broad Spectrum de-wormer such as fenbendazole (Panacur, Safe-Guard); oxibendazole (Anthelcide EQ)
March 1: Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin), for general de-worming.
April 15: Moxidectin plus praziquantel (Quest Plus or Combo Care), to treat encysted strongyles and tapeworms.
June 15: Either double dose pyrantel pamoate (Strongid, Strongyle Care) OR single dose praziquantel combination product with either ivermectin or moxidectin (Equimax, ComboCare, Quest Plus, Zimectrin Gold), to treat tapeworms.
August 15: Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin) for bots; first dose.
October 15: Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin) for bots; second dose.
November 25: Broad Spectrum de-wormer such as fenbendazole (Panacur, Safe-Guard); oxibendazole (Anthelcide EQ)

For foals 60 days to 1 year of age:
Please contact the office for recommendations specific to your foal's needs.

De-worming: Rethinking Parasite Control

Parasite resistance to the drugs we most commonly use is becoming an increasing concern in our horse populations. For many years veterinarians and horse owners have been using rotational de-worming to combat parasites. This aggressive de-worming protocol may now be contributing to the development of resistant parasites. This could eventually lead to a devastating parasite problem: in the not so distant future we could be faced with a parasite population that does not respond to ANY of the drugs currently available. If this occurs, we would essentially be back at square one with parasite control (think 1970s!) Prior to effective parasite control, horses were plagued with unthriftiness, plus a marked increase of colic incidence and premature death.

In an effort to reduce the development of resistance to de-worming drugs, Equine Veterinary Service has adopted a new strategy for combating parasites in our horse populations. It is IMPERATIVE that you, our clients, help us maintain the effectiveness of the currently available de-worming drugs by participating. Using published, evidence-based research we have changed our de-worming recommendations.

Our goal with de-worming will be to de-worm as needed, based upon the results of quantitative fecal exams. These tests provide much more information than a routine fecal used for basic screening. The quantitative fecal exam actually provides the number of parasite eggs per gram of feces that exist in an individual horse. We will use these numbers to determine the ideal de-worming strategy for individual horses and barns.

Just like certain people are more susceptible to colds and flu, certain horses carry a much higher parasite burden than others. In fact, research has shown that 20% of the horse population harbors 80% of the parasite burden. Clearly, as these horses are the ones contaminating the environment, they are the ones that need to be de-wormed most regularly. This does NOT mean that we stop treating other horses.  It is important to continue a modified de-worming program for all horses, with the horses with the highest worm burdens being medicated most frequently.

What does this mean for you now? We recommend testing all horses' manure with a quantitative fecal test using the McMaster Method in the spring and again in the fall each year. Based upon individual results, we will help design a program for your horse(s) and the environment they live in. While this program certainly involves more effort, we feel that it is exceedingly important to begin to tackle the increasing problem of parasite resistance. We hope you will participate and we are happy to discuss any questions/concerns that arise!