Why Test
Parasite Resistance
Resistance develops when the recommended dose of dewormer does not kill 100% of the parasites inhabiting an animal. This process of selection allows resistant survivors (those not killed by the dewormer) to mate with other resistant worms and subsequently pass resistant genes onto their offspring. Resistance becomes a clinical problem when there are a high number of resistant worms within the treated population leading to treatment failure and clinical disease. The rate at which modification to the parasite gene pool occurs within a given population varies depending upon a number of factors including: the frequency of exposure to a particular class of anthelmintic, the immune status of the individual animal and the size of the parasite population in refugia (the population that has never be exposed to anthelmintics).
The following is a comprehensive compilation of peer reviewed information regarding Fecal Egg Count interpretations and treatment regimens from the leading parasitologists.
A successful deworming program must combine the following:
Epidemiological principles of nematode control.
Determining which drugs remain effective on each farm.
Using the correct drug for the correct parasite at the correct time of the year.
Determining which animals require less or more frequent treatment by performing Fecal Egg Counts.
Evaluating the overall success of the worm control program by monitoring the FECs of all livestock on the property at regular intervals.
“Think about it this way: You would never randomly use an antibiotic to treat a suspected infection. It wastes money, it wastes therapeutic time just when speed is of the essence and it increases the risk for developing resistant pathogens. That same school of thought must now be applied to equine dewormers.”
General Recommendations:
Deworm as needed during the grazing season based on post treatment Fecal Egg Counts [FECRT tests.] Consult Our Equine Deworming Guide. And our Small Ruminant Deworming Guide.
For in-depth recommendations and answers to your specific concerns, book a virtual consultation with our expert parasitologist, Dr. Eva.
The concept of zero tolerance for small strongyles should be abandoned, as some degree of parasitism is necessary to stimulate an immune response.
Individual animals 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 animals 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.
