Emerging resistance to dewormers among internal parasites is a global problem in sheep, goats and other livestock that is now beginning to affect cattle production in North America. Scientists believe though, that the industry can limit the development and impact of resistant parasites through changes in management and control strategies.

Toward that goal, the FDA and American Veterinary Medical Association will present a webinar titled “Resisting Resistance: FDA’s Antiparasitic Resistance Management Strategy,” on Tuesday, October 14, 2014, from 11am to 12pm EST (10-11am CDT). The one-hour webinar is free of charge and open to the public.  It will focus on antiparasitic resistance in U.S. grazing livestock, FDA’s response to this animal health threat, and the current science related to slowing down further development of resistance.

According to the FDA, antiparasitic resistance is the genetic ability of parasites to survive treatment with an antiparasitic drug that was generally effective against those parasites in the past. After an animal is treated with an antiparasitic drug, the susceptible parasites die and the resistant parasites survive to pass on resistance genes to their offspring.

To help combat this emerging problem, the FDA’s Center for Veterinary Medicine (CVM) started the Antiparasitic Resistance Management Strategy (ARMS), which promotes sustainable use of approved antiparasitic drugs in grazing animals.  Last year, CVM outlined its strategy in a publication titled “Antiparasitic Resistance in Cattle and Small Ruminants in the United States: How to Detect it and What to do about it.”

A key step in slowing the development of resistance is to identify and monitor when and where resistant worms occur. Where resistance is suspected, such as when cattle do not seem to respond to parasite treatments that have been effective before, veterinarians can use fecal egg count reduction (FECR) tests to estimate the number of eggs present before and after treatment. Substantial numbers surviving treatment suggest a need for a change in treatment protocols. A next step can be to use a relatively new polymerase chain reaction (PCR) test to diagnose the type or genera of parasites present before and after treatment.

The September issue of Bovine Veterinarian magazine includes an article detailing the PCR test for parasites and how the information it provides can help veterinarians and their clients develop more effective control programs and minimize resistance issues. Also, watch for the October issue of Drovers/CattleNetwork, which includes a feature article on the potential benefits of parasite diagnosis.

Click here for more information on the FDA webinar on antiparasitic resistance.