Parasite control is an important
part of every equine health care program. Today, it’s no longer
enough just to know what worms are bugging your horse. Now,
you need to understand the basics of parasite resistance to
ensure your program is effective.
If you already have enough to keep track of,
don’t worry — veterinarians are your ally in keeping all the
information straight. They also will help with developing
and monitoring your parasite control program to ensure effectiveness
and to keep resistance at bay.
When considering your parasite control program,
there are 10 key things to keep in mind:
1. Resistance is a real threat. With no new
parasite control products on the horizon, it’s important to
start protecting our ability to control parasites by keeping
current products effective.
2. Know the product class. Nearly all equine
parasite control products belong to one of three different
classes: benzimidazoles, macrocyclic lactones and pyrantel
pamoates.
3. Use what works. It’s important to know
what class you’re using because many experts believe macrocyclic
lactones is the only class of medications that is capable
of controlling key parasites in adult horses.1,2 For example,
ivermectin, one of the two main active ingredients in ZIMECTERIN®
Gold (ivermectin/praziquantel), is part of the macrocyclic
lactones class.
4. Don’t rotate without reason. Many experts
believe rotating through a series of different drugs will
mask the effects of using products with resistance problems.3
In fact, information shows rotating through different parasite
control products does not appear to slow the development of
resistance.4
5. A few worms are OK. In the past, the goal
of parasite control programs was to completely eliminate all
parasites. However, today’s programs should be focused on
reducing transmission of parasites, keeping worm burdens below
harmful levels and treating clinically affected horses. Maintaining
a population of parasites that can be killed by dewormers
is an important factor in delaying the development of resistant
parasites.2
6. Get the information. By performing a fecal
egg count reduction test (FECRT), your veterinarian can help
identify the key parasite threats on your premises, if the
products you are using are working and what products should
be included in your parasite control program.5
7. Know what’s on your farm. The species and
amount of parasites attacking horses can vary by geographic
area. For instance, tapeworms may be found more frequently
in the upper Midwest or southeastern parts of the United States,
rather than the west coast.6
8. Get it done right. FECRTs can easily be
misinterpreted if samples are collected, handled or analyzed
improperly. Be sure these tests are properly conducted by
veterinarians or by independent, reputable laboratories.
9. Treat the “problem” horses. It’s estimated
that 20 percent to 30 percent of the horses on a farm put
out about 80 percent of the parasite eggs, while other horses
tend to shed fewer worm eggs whether treated or not.2 By focusing
treatments on horses shedding most of the worm eggs, you can
help maintain a population of susceptible parasites, reduce
the risk of resistance and help keep horses healthy.2
10. Guarantee success. We are all concerned
about keeping our horses healthy, and the best way to make
certain your product works is to look for products with a
100 percent product satisfaction guarantee.
With several different kinds of parasites
waiting to attack horses and confusion surrounding the resistance
problems of some parasite control products, it is harder than
ever to be sure all key parasite threats are controlled. Keep
these 10 tips in mind and your veterinarian’s number handy,
and you’ll be set for the new era of parasite control.
