The goal of deworming should be:
The right drug, at the right dose, at the right time, in the right horse.
The following is a comprehensive compilation of peer reviewed information regarding egg count interpretations and treatment regimens from the leading equine parasitologists.
A successful deworming program must combine the following:
(1) epidemiological principles of nematode control
(2) determining which drugs are effective on each farm
(3) using the correct drug for the correct parasite at the correct time of the year
(4) determining which horses require less or more frequent treatment by performing FEC
(5) evaluating the overall success of the worm control program by monitoring the FECs of all horses on the property at regular intervals.
General Recommendations:
- Deworm horses shedding greater than 200–250 EPG before spring turnout and as needed during the grazing season based on post treatment FEC’s.
- Treat for tapeworms (with praziquantel) before going on pasture in the spring. If tapeworms are a big issue, another treatment can be done in the fall. Treat for bots after first freeze in the fall.
- The concept of zero tolerance for small strongyles should be abandoned, as some degree of parasitism is necessary to stimulate an immune response.
- Individual horses vary greatly in their susceptibility to internal parasites; some limit infection almost entirely even without deworming drugs, while others carry very high parasite loads even with regular deworming. Thus, we can also reduce anthelmintic use by only deworming the horses that really need it.
- Anthelmintics are not the only control measures for internal parasites. For example, removing feces from the environment every few days ensures that infective larvae are hauled off in the wheelbarrow.
Implementation of such programs requires close work with a veterinarian
