The Importance and Reasoning for Equine Fecal Egg Count Exams

The fecal egg count exam is an important tool veterinarians use to determine parasitic infections in horses.  A fecal egg count exam is a simple, fairly inexpensive test that provides information about a horse’s health and if the present deworming program is effective.


When a veterinarian orders a fecal egg count exam, they are looking for intestinal parasites.  Intestinal parasites reproduce by laying eggs which pass through the horse’s gastrointestinal system via feces.  If there are eggs in the feces, then there are living adult parasites somewhere within the horse’s intestines.


A typical fecal test will report on two important findings:


  • Are there any eggs in the feces?
  • If there are, what is the type of parasite laying the eggs (strongyle, roundworm, whipworm, tapeworm, pinworm) and how many eggs are there, reported as “eggs per gram” (or EPG).


Traditionally, a horse with more than 200 eggs per gram of feces would be considered a candidate for deworming treatment (although this range can vary between veterinarians).  Some horses may require as few as two deworming cycles per year while others may require five or more.  Appropriate deworming products to use may vary from horse to horse, farm to farm and veterinarian to veterinarian.


For reporting on fecal parasitic egg burden in equines, New England Horse Labs offers two types of fecal exams:  Qualitative and Quantitative.  In our experience, the qualitative (modified Wisconsin) analysis is more precise for finding and identifying eggs in low-burdened animals, thus, reducing the number of false-negatives.  The quantitative (McMaster’s) analysis is valuable for establishing a baseline and for monitoring any patient on a deworming program.