Doing Your Own Fecal Egg Counts for Horses
About a year ago, I decided to take Dr. Kellon’s short course on equine de-worming. I knew about the changing recommendations on deworming and I wanted to be up-to-date and informed when it came to equine parasites. In this course, one of the things I learned more about was doing fecal egg counts (FECs). FECs aren’t foolproof, but they are considered to be the most reliable method of parasite diagnosis.
I checked into getting FECs done with several different vets in my area first. Two of them told me I had to bring all my horses to them in order to get fresh samples, and the other said I could bring fresh samples in to him.
I was going to take the samples in, but then I got to thinking about it. I would have to do the initial FECs, de-worm my horses (if needed), and then take in another sample two weeks after administering the de-wormer to see if it was effective. I saw that even at $15-20 a horse, this could add up pretty quickly. (However, it would still likely be cheaper than a rotational deworming program as I wrote about in this article for The Horse).
So, being the economical-minded person that I am, I decided to invest in a good microscope and a FEC kit and learn to do FECs myself. I got this one from Farmstead Health Supply.
I was nervous the first time I took a sample and brought the baggie into the house. What would I find in my horses’ poop? Did I really want to know? Well, even though ignorance can be bliss–yes, I really did want to know!
The procedure outlined in my kit was fairly simple. I used the ‘flotation method’, which is most commonly used in veterinary offices. Here are the basic steps:
- Collect fresh sample (1 piece of manure) in a plastic baggie–write horse’s name on baggie for identification.
- Observe the sample and record observations such as color, consistency, etc.
- Mash sample with a popsicle stick (or plastic knife). Take about 1/2 tsp. of the manure and add to 40 mL of flotation solution (this came with the kit, but you can also make your own.) Allow sample to sit for 1-2 minutes. Mix until well blended.
- Pour solution through strainer into a clean plastic cup. Then pour the contents of the cup into a vial (came with kit) until it is slightly over-full and has a bubble on top. Place a cover slip on top of vial and allow to sit for 15 minutes.
- Place cover slip onto clean slide, wet side down.
- Examine slide using the 10X objective.
As you examine the slide, go in an up-and-down motion, starting at one side of the cover slip and slowly rotating toward the other side. This way you will see all the contents. Use a worm egg identification chart (provided with kit) and record all egg-types you see.
Each circular area you see through the microscope is referred to as a field. Count and record the eggs you see in each field.
According to the Farmstead Health Supply kit directions, an average of 0-1 ova in each field means a low level of infestation. 2-3 ova means a moderate level, and 4+ means a heavy infestation.
A more precise measurement system is known as the McMaster method. This method employs a slide which is pre-marked with a grid system. You then count the eggs within each grid. This is what I would like to eventually buy and use.
The most common types of eggs you will see in a sample are strongyles and ascarids (round worms). The ascarids are usually only present in young horses though.
I will caution you against a mistake that I made in doing FEC’s at first though. Ascarid eggs and air bubbles can appear very similar. Air bubbles, however, are perfectly round and usually black on the outside and whitish in the center. I thought my horses were loaded with ascarids at first! (I took my slide in to my vet, to make sure this wasn’t the case.)
Doing FEC’s has definitely been an eye-opener for me. When you can actually see and identify which parasites your horses are infected with, you can develop a more targeted approach to dealing with them. You can also assess the effectiveness of a de-wormer with the FECs and this is very important to combat resistance.
Coming soon–I will tell you about a natural de-worming product that I used and the results!
For more information on DIY fecal egg counts, I recommend these articles: