NOTE – be sure to read to the very bottom of this article for a surprise ending you won’t believe (but it’s true!)

I just sat through a lecture given by a very intelligent parasitologist. He stirs horse poop and water together, then looks at it under a microscope. Sound like fun to me!

I want to give you the important points of his talk and then give you some ideas of my own.

The recent movement to take fecal exams before administering dewormers to your horse has taken a rapid hold in the veterinary community, and there is a good reason for it. To understand this, you need to go back to the mid-1970s when the first commercial packets of chemicals came out.

Forty years ago, veterinarians realized that internal parasites were a problem in horses, causing everything from unthriftiness to colic to death. Companies took notice and developed chemicals that killed the worms with only mild discomfort to the horse. Unfortunately, most horses turned their nose up to these powders added to their feed. Before long, the companies developed pastes that were only as effective as the person’s ability to get it into their horse’s mouth.

About 1983, ivermectin became an injectable for horses that veterinarians would use a needle and syringe to administer. After several horses died from the injection, it was reformulated into a liquid and squirted into the mouth. Then it became a paste, and many more compounds and mixes of compounds became available. Along with these pastes came the owners taking over the responsibility of deworming their horses. The vets said fine – they had bigger fish to fry.

Few realized that not all the worms were being killed by the chemicals and by the indiscriminate use, so the owners were selecting resistant populations. The solution is to have your vet do a fecal exam and then selectively deworm your horses.

Most people think that this is just the vets trying to make money. However, in Europe, several countries are now making dewormers a prescription product and owners can no longer purchase them. The vet now needs to diagnose a parasite infection, but there are some problems.

The first problem with fecal egg counts is that every lab does them differently. However, the solution is right around the corner, thanks to an iPhone app they have developed. The manure is mixed with water, placed on a filter, then stained, and photographed by the phone. In a few seconds, the computer not only counts the stained eggs but also identifies what specie of worm it belongs to. This is important because no one product is available today that “gets ’em all.”

There is another problem with fecal egg count tests. Not every horse sheds eggs equally. There is always one in a herd that is what they call a “high egg shedder.” In other words, one horse will have a million eggs per gram, and the others will be 1000 eggs. So the high shedder needs to be identified and treated. And here’s a funny thing about that. The high egg shedder is usually the healthiest horse on the farm!

Now for my take on this.

Manure is picked up daily in the paddock the old-fashioned way.

I say now, and I’ve always said, that sanitation is the best way to control internal parasites on a farm. First, keep the mouth of the horse away from the manure. This is done by cleaning the stalls daily and picking clean the paddock at least every other day. Cold and wet do not kill them. A covering of snow keeps their mouth away from the ground, but when melted, the parasites have access to the horse again.

We have depended on the use of dewormers because we, as horse owners, don’t have the time to do the clean-up necessary to provide a clean environment. Not only does creating a clean environment make sense, but an extremely well-done scientific study was done in the 1980s that proved that if the horse had only limited exposure to manure (as in they were grazing freely the way nature intended them to be), then their immune system was perfectly capable of defending against the occasional parasite. As a result, many parasitologists now think it is important to have exposure to the worms to keep the immune system sharp.

Parasite control
A gas-powered manure vacuum is attached to an ATV.
The Greyston manure vacuum is pulled with a small riding tractor. A large diameter hose is attached to the hole next to the engine. While driving through the paddock, the end of the hose is directed over a manure pile and sucked into the blue container. Manure can then be composted and used in the garden.

Many horse owners don’t want to put “chemicals” into the horse. Rather than work to clean the environment, they go to “natural” products such as diatomaceous earth. However, this still avoids the fact that the horse eats where he defecates. In the “natural” environment, the horse would eat here, defecate there, and graze many miles away in a week. This doesn’t occur when a fence confines a horse. Worse is when there are too many horses for the pasture.

I believe that shortly, the control of parasites will be turned over to the vet. But you can do something right now to improve your horse’s health. First, begin to clean up the horse’s environment.

Piles of manure are picked up daily on this farm.
Piles of manure are picked up daily on this farm.

A Side Note

What did your parents deworm you with when you were growing up? What chemical do you use now? Did you know that the dewormers we use in our horses are approved for use in humans?

Our parasite control includes knives and forks, washing our hands with soap, and eating at a table away from the septic system. This keeps the manure off our fingers and away from our mouths.

If you don’t believe me, here is a picture I took last year at our local Walgreens. This is Strongid – the same chemical we use in our horses – for sale on their shelf for pinworm relief. Not a popular item because humans have been trained to be clean. It’s time we did the same for our horses.

A package of Strongid liquid dewormer for human use on the shelf of the local Walgreens pharmacy.

Back to top


Remember, you can also start a discussion in the forums for a more in-depth experience!

This site uses Akismet to reduce spam. Learn how your comment data is processed.

  1. I pick up the manure in my 2 acre field daily. Yes, daily. I use a bedding fork and it takes about 30 minutes per day to clean up after 2 horses and dump the manure away from the field. Also, I have awesome arm, shoulder, and upper back muscles 😉