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Parasites of focus Equine Internal Parasite Risk Diagram

For adult horses, small strongyles and tapeworms are the key parasites of concern per American Association of Equine Practitioners guidelines.1 Roundworms continue to be the key parasite of concern in foals.1 Ninety percent of internal parasites like small strongyles, tapeworms, pinworms, roundworms, bloodworms and threadworms come from the environment your horse is exposed to every day.2

Even with no outward signs, parasites can damage vital organs and impact your horse’s health by:

  • Decreasing nutrient absorption
  • Leading to colic or pneumonia
  • Causing irreversible lung damage
  • Impairing performance
  • Stunting growth
  • Causing weight loss
  • Impairing coat condition

Deworming too often can lead to resistance

When parasites are overexposed to certain treatments, they can become resistant. Small strongyles have shown widespread resistance to fenbendazole, one of the oldest deworming active ingredients.


Accurate dosing can decrease resistance

If you underdose your horse when deworming, you could be contributing to the development of parasite resistance. Treatment doses are based on the weight of the animal. Use a scale or weight tape to determine each animal's weight before deworming.


Each horse needs tailored parasite control

The most important tool in your parasite control arsenal is your veterinarian. Your veterinarian can perform a fecal egg count test to determine which horses in your herd need treatment and which don't. Once you have a baseline established, your veterinarian can work with you to develop an Individualized Deworming program.


Do not use QUEST Gel or QUEST PLUS Gel in foals less than 6 months of age or in sick, debilitated and underweight horses. These products should not be used in other animal species, as severe adverse reactions, including fatalities in dogs, may result.

1 American Association of Equine Practitioners. AAEP Parasite Control Guidelines. Available at: Accessed January 29, 2016.
2 Reinemeyer, C, Nielsen, M. Handbook of Equine Parasite Control (2013). Environmental Factors Affecting Parasite Transmission, Page 45. Accessed January 29, 2016.




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