The Piedmont Equine Practice recommends deworming horses on a conservative schedule that is based on performing Fecal Egg Counts (FEC). This is due to the rising concern for parasite resistance to our current dewormers and is based on numerous scientific research studies. Please note: even if your horse’s Fecal Egg Count is zero, a base schedule of deworming is still recommended as the sample provided may not have been representative or the horse may not have been shedding parasite eggs at the time of sample collection.
Deworming Schedule for:
“Low Shedders” (under 50 eggs per gram on Fecal Egg Count)
Deworming Schedule for:
“Moderate Shedders” (50-200 eggs per gram on Fecal Egg Count) AND
“High Shedders” (200+ eggs per gram on Fecal Egg Count)
* New arrivals to the herd with an unknown deworming history should have a FEC done and be treated with Quest. Two weeks later a second fecal sample should be taken and analyzed (Fecal Egg Count Reduction Test) to determine what resistant worms, if any, the horse is carrying. If tapeworms are evident on fecal at any time, QUEST PLUS should be used instead.
* When bringing fecal balls to the clinic for the FEC, one ball per horse is sufficient.
Guidelines for Deworming Foals:
* Dose at least 25% higher than the foal’s estimated body weight.
* Do not deworm until at least 60 days of age.
* Do not use Quest (moxidectin) or ivermectin until around 6 months of age (weaning). Primary worm burden prior to 6 months of age is Ascarids (resistant to moxidectin/ivermectin), so deworming should focus on removing this burden (e.g. through use of benzimidazoles).
* After about 9 months of age, deworming should focus more on removing strongyles (using moxidectin) than removing Ascarids (using benzimidazoles).
* Schedule Fecal Egg Counts at 6 and 12 months of age. Deworming strategy may be altered depending upon the results of the FEC.
Deworming Schedule for Foals (under 12 months old):