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 basically 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 though you need to go back to the mid 1970’s when the first commercial packets of chemicals came out.
40 years ago veterinarians had 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 of the 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 came out as an injectable vets 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 basically said fine – they had bigger fish to fry.
What few realized was that not all the worms were being killed by the chemicals and by the indiscriminate use, the owners were selecting for resistant populations. The solution is now 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 with this.
The first problem with fecal egg counts is that every lab does them differently. The solution is right around the corner thanks to an iPhone app they have developed. The manure is mixed with water and placed on a filter, then stained, then photographed by the phone. In a few seconds the computer not only counts the stained eggs, it identifies what specie of worm it belongs to. This is important because there is not one product 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, 1 horse will have a million eggs per gram and the others will be 1000 eggs. 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
I say now and I’ve always said that the best way to control internal parasites on a farm is sanitation. 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 does not kill them. A covering of snow keeps their mouth away from the mans, but when melted, the parasites have access to the horse again.
The reason we have depended on the use of dewormers is simply that 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 1980’s that proved that if the horse had only a limited exposure to manure (as in they were grazing freely the way nature intended them to be), then their immune system was perfectly capable to defend against the occasional parasite. In fact, many parasitologists think it is important to have some exposure to the worms to keep the immune system sharp.
There are many horse owners that don’t want to put “chemicals” into the horse but rather than do the work to clean the environment, they go to “natural” products such as diatomaceous earth. This still is avoiding the fact that the horse is eating where he defecates. In the “natural” environment, the horse would eat here, defecate there, and in a weeks time be grazing many miles away. This just doesn’t occur when a horse is confined by a fence. Worse is when there are too many horses for the pasture.
I believe that in the near future the control of parasites will be turned over to the vet. But you can do something right now to improve the health of your horse. Begin to clean up the horse’s environment.
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 all keeps the manure off of our fingers and away from our mouths.
Just in case 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.