
While well-intentioned, not all clients may realize that frequent deworming practices, such as every 30 to 60 days, have led to parasitic resistance to many treatment options.1
Helping horse owners understand the “why” behind a shift to less frequent deworming can help veterinarians take steps to preserve the efficacy of the dewormers that are currently available. Spring, summer or fall wellness visits are an ideal time to discuss the targeted parasite treatment shift with your clients. In this article, I unpack key talking points and resources to help guide these discussions with horse owners.
Educate clients on the value of a fecal egg count
It may be helpful to remind clients that conducting fecal egg counts is now quicker and easier than ever. In ~10 minutes,2 you can have reliable results for the detection of roundworm and strongyle eggs with the VETSCAN IMAGYST™ platformOpens in a new window. This new technology utilizes artificial intelligence to read and calculate fecal egg counts with up to 99% accuracy as compared to a boarded parasitologist.2 Fast results, at the time of your exam, help you develop a targeted treatment plan for each individual horse—saving you time.2
Pro-tip reminder: Healthy, low-shedding adult horses most often need a deworming treatment at the beginning and end of their respective grazing seasons.3 High shedders may need more frequent deworming treatments.
Helping clients choose a dewormer
With so many products available, horse owners may not know which active ingredients effectively control the major parasites of concern. The AAEP offers these guidelines:
- For healthy adult horses: According to the AAEP’s Internal Parasite Control GuidelinesOpens in a new window, moxidectin, the active ingredient in Quest® GelOpens in a new window (moxidectin) is the experts’ treatment of choice against small strongyles in mature horses.4 Praziquantel, the second active ingredient in Quest® Plus GelOpens in a new window (moxidectin/praziquantel), treats tapeworms. Click hereThis links to a pdf file for a deworming guide for this equine age group from Zoetis.
- For foals: Choose Anthelcide® EQ Paste (oxibendazole) and/or Strongid® Paste (pyrantel pamoate) for the critical treatment of ascarids in young foals. Click hereThis links to a pdf file for foal deworming recommendations from Zoetis.
- For 1- to 2-year-olds: The AAEP’s Internal Parasite Control GuidelinesOpens in a new window advise that 1- to 2-year-olds should be treated like high shedders, with a focus on treating small strongyles and tapeworms.3 Learn moreThis links to a pdf file about the latest deworming recommendations for this equine age group from Zoetis.
Analyzing product differences
Moxidectin is the experts’ active ingredient of choice for small strongyles because it treats both the encysted larval and adult stages of this important parasite.5 Both Quest Gel and Quest Plus Gel are formulated with moxidectin, which is also effective against large strongyles (bloodworms), bots, pinworms, hairworms and stomach worms.
- In studies, moxidectin was significantly more effective than the active ingredient in Panacur® POWERPAC at treating small strongyles4,5,6
- Quest Plus Gel has a second active ingredient, praziquantel, for the treatment of tapeworms, typically recommended at the end of the grazing season6,7
**Per the 2024 AAEP Parasite Control Guidelines, multiple studies show widespread small strongyle (cyathostomin) resistance (lack of efficacy) to benzimidazoles (fenbendazole and oxibendazole).
†American Association of Equine Practitioners. Internal parasite control guidelines.Opens in a new window Accessed June 24, 2024.
Target the right parasites at the right times
Horse owners may think that more is better, but continuing an 8-week rotational deworming program can increase parasitic resistance to treatment options.3 Research has shown that by focusing on the high shedders in a herd, we can limit environmental contamination and reduce the amount of dewormer used on a herd basis.3 Using less product saves your clients money and maintains healthy refugia.
As veterinarians, we know the importance of healthy refugia; however, horse owners may be unfamiliar with the term. Help horse owners understand that this is primarily the population of parasite eggs and larvae on the pasture/environment that are not impacted when we treat the horse. This is important since we want to maintain the refugia of parasites that remain susceptible to our anthelmintic treatments. Explaining this may help clients more readily embrace a targeted deworming treatment plan.
With this quizOpens in a new window, your clients can learn more about the deworming plan you recommend for their horse. For more information on deworming, I recommend sharing the following blog with clients, “How to Deworm Your Adult Horse,”Opens in a new window which contains a video that unpacks targeted, seasonal deworming insights and tips.
Important Safety Information
Do not use Quest Gel or Quest Plus Gel in foals less than 6 months of age or in sick, debilitated and underweight horses. Do not use these products in other animal species, as severe adverse reactions, including fatalities in dogs, may result. Consult your veterinarian for assistance in the diagnosis, treatment, and control of parasitism.
References
- Reinemeyer C, Nielsen M. Environmental factors affecting parasite transmission. In: Handbook of Equine Parasite Control, 2nd edition. Wiley-Blackwell;2018.
- Zoetis Inc. Data on file. Study report no. DHX6Z-US-22-131 (D6131).
- American Association of Equine Practitioners. Internal parasite control guidelines.https://aaep.org/resource/internal-parasite-control-guidelines/Opens in a new window. Accessed June 24, 2024.
- Mason ME, Voris ND, Ortis HA, et al. Comparison of a single dose of moxidectin and a five-day course of fenbendazole to reduce and suppress cyathostomin fecal egg counts in a herd of embryo transfer-recipient mares. J Am Vet Med Assoc. 2014;245(8):944-951.
- Reinemeyer CR, Prado JC, Nielsen MK. Comparison of the larvicidal efficacies of moxidectin or a five-day regimen of fenbendazole in horses harboring cyathostomin populations resistant to the adulticidal dosage of fenbendazole. Vet Parasitol. 2015;214:100-107.
- Bellaw JL, Krebs K, Reinemeyer CR, et al. Anthelmintic therapy of equine cyathostomin nematodes—larvicidal efficacy, egg reappearance period, and drug resistance. Int J Parasitol. 2018;48:97-105.
- Proudman CJ, French NP, Trees AJ. Tapeworm infection is a significant risk factor for spasmodic colic and ileal impaction colic in the horse. Equine Vet J. 1998;30(3):194-199.
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