Equine Fecal Egg Count - Manure Matters!

Updated August 28, 2023
pile of horse manure in a paddock

Many owners deworm their horse for the first time of the year in the spring.  Some owners may already be on their second or third deworming. However, there’s something else you can do to help protect your horse from parasites, and that’s having a fecal egg count performed.

What is an Equine Fecal Egg Count?

A fecal egg count (FEC) measures the number of strongyle and roundworm eggs your horse is passing in each gram of his manure. Having a fecal egg count done for your horse is the first step in planning and executing your horse’s deworming program.

Most veterinarians will perform an FEC for your horse, however, if that’s not an available service, SmartPak offers a mail-away Equine Fecal Test Kit.

Difference Between Fecal Tests for Large and Small Animals

When you send a sample to your veterinarian or independent laboratory, you get back a number like 50 EPG (eggs per gram) or 500 EPG. This is called a quantitative test.

When you take a sample of your dog’s stool to your veterinarian, the clinic runs a qualitative test. A technician performs a fecal flotation to look for the presence of roundworms, hookworms and other parasites. You get back an answer like “yes, your dog has roundworms” or “no, your dog does not have hookworms.”

Why the difference? It’s partly because some of the parasites that dogs and cats get can also be picked up by people. So, we want smaller, companion animals that live with us to be completely parasite-free.

But it’s mostly because horses, being grazers, will never be completely free of parasites. However, owners need to know if their horse has a high load of parasites and need to be dewormed to:

  1. protect themselves from problems like colic, weight loss, and diarrhea and
  2. protect the pasture from a high number of eggs being passed onto it.

When to Fecal Test Your Horse

equine fecal egg test by SmartPak

Have a FEC done before deworming your horse in the spring and fall. If you only have budget for one FEC per year, do it in the beginning of the grazing season for your area.

Parasite transmission season usually starts in the spring in northern climates, so this is a great time to test. The results will help you and your veterinarian decide on the best next steps to take in your parasite control program.

Have a second FEC performed 10 to 14 days after this first deworming. This is called a fecal egg count reduction test and the results help you determine if the dewormer worked. Scientists are discovering more resistance to commonly used dewormers, so it’s important to make sure there are less eggs in your horse’s manure after the deworming.

At the end of the grazing season (typically the fall in northern climates), it’s recommended to have another FEC completed. Depending on the results of this test, you may or may not have to use dewormer. If your horse is under three years old, speak with your veterinarian as young horses follow different FEC and deworming protocols.

Understanding the Test’s Results

If your horse’s results come back with a low number (less than 200 EPG), this could indicate that your horse has good natural immunity to strongyles and may not need dewormer as frequently.

However, if the number is more than 200–250 EPG, your horse may be a considered a chronic shedder. This is a horse who may not show signs of parasitism but is carrying lots of adult worms that are laying eggs. Therefore, he is spreading the parasite eggs all over your pasture to the other horses. Chronic shedders may need to be dewormed more often than other horses.

Keep in mind, a FEC is not used to determine parasite burden in a horse, it's to identify the horse as a low, medium, or high shedder. A negative FEC result does not mean your horse is parasite-free. He still has intestinal parasites in his system; however, the number of eggs being shed is too low to be detected by the FEC. Also, remember tapeworms don’t show in the test, nor do they indicate the presence of encysted small strongyles.

Video on How to Read Equine Fecal Test Results

To learn more about reasons to perform an FEC and recommendations for sampling and storing, read the American Association of Equine Practitioners’ Parasite Control Guidelines.

SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.