Deworming with Diatomaceous Earth for Horses

 

 

What is Diatomaceous Earth

 

• Diatoms are fossils of small organisms found in oceans and other bodies of water. These diatoms were single-celled organisms known as phytoplankton, and luckily for some industries today, their hard silica fossilized structure has a few uses.

• The structure of these fossilized remains has sharp edges, meaning their abrasive nature could directly impact parasites.

This article has a couple of amazing photos of DE up close and personal.  

 

The structure of DE

 

• The overwhelming majority of DE is amorphous, meaning it has no defined shape. Some types of diatomaceous earth have crystalline silica.

• Diatomaceous earth is a fine powder whose particles are roughly 3/1000 of a millimeter up to 1 mm in size. Typically, it’s about 15/1000 mm. It’s a very porous white powder with low density, and in your hand feels like an exfoliant.

Grades of DE

 

Depending on the amount of crystalline silica, DE falls into one of these categories:

 

Food grade DE

 

• This category has less than 2% crystalline silica. The FDA, USDA, and EPA agree that this category can be used for insect control and some anti-caking uses in food and agriculture. You can also market this DE as a dietary supplement.

• When ingested, very little is absorbed. Instead, it’s on a fast track to being excreted. When inhaled, it can cause reversible lung trouble, but the lungs can quickly clear it.

Filter grade DE

 

• This category usually contains over 60% crystalline silica, which you’ll find in filter systems. Filter grade is toxic to people and animals and inappropriate for combatting insects. It can cause silicosis, severe lung irritations and problems, and chronic bronchitis when inhaled due to its smaller size. Lungs and lymph nodes can collect this silica over time. Also, it’s a carcinogen.

DE is great for gardens

 

 

DE is a carcinogen

 

• Diatomaceous earth is a Group 3 carcinogen according to the International Agency for Research on Cancer (IARC).

• A Group 3 carcinogen means that existing research about DE does not have enough evidence to consider it carcinogenic to humans.

• BUT! We know that diatomaceous earth is primarily amorphous – which is fine; it’s safe and edible.

• Another BUT! The presence of crystalline silica is a Group 1 carcinogen, and it causes cancer in humans.

Research about cancers in rodents

 

• In a study using mice, there was an increase in lung cancers when mice were forced to breathe DE for an hour a day for a year. When rats ate a large dose of silica for two years, researchers did not see an increase in the number of cancers that formed.

This succinct article has many FAQs about DE and its carcinogenic factors.

 

 

 

 

DE and Insect Control

 

• DE’s rigid, scratchy texture makes it helpful in insect control. Bugs like cockroaches, garden pests, fleas, bed bugs, and more have tough exoskeletons that protect their bodies like armor. When they contact diatomaceous earth, the scratchy diatomaceous earth acts as a natural pesticide by damaging the exoskeleton. The insect will dry out from those wounds.

 

• For insect control, the area must be dry. Using it inside for flea control may damage your vacuum motor as you clean your house.

 

• A website dedicated to selling DE states that it won’t work when wet, but you can get it wet.  It’s back to desiccating insects with exoskeletons when it dries out.  

 

• There is a long history of using DE as an insecticide, dating back thousands of years. In the US, it was noted in 1880 that DE helps control cotton worms in fields and pastures. Across the world, diatomaceous earth has been formally studied since the early 1900s, concluding that it does, indeed, act as an insecticide.

 

• Perhaps the insect control portion of DE’s extensive resume is where the deworming for horses narrative began.

To read a scientifically based history of DE, read this fascinating article.

 

The jump to using DE as an equine dewormer

 

• Because it does so well as an insecticide out in the world, it was presumed that DE would work on internal parasites and be the next great, effective dewormer. This is a logical conclusion!

• This leap to using diatomaceous earth for horses as a dewormer also comes from the fact that more and more equine internal parasites are resistant to the currently available treatments. And there are ZERO new medications in development. Kind of a pickle.

• In fantasy land, diatomaceous earth does work perfectly for horse parasite control, but in reality, there is science that says otherwise.

Intestinal parasites zap nutrients from your horse and can block digestion.

 

Medications vs. Supplements 

 

• There’s a key difference between dewormers and DE for horses. Dewormers are medications, while diatomaceous earth for horses is a supplement.

Medications

 

• Rigorously tested using scientific methods and multiple studies.
• Ingredients are transparent and verified by quality control from the FDA.
• Every part of development – from labels to manufacturing – must meet rigorous standards.
• Medications are specific formulations that treat and may cure diseases.
• Medications are considered unsafe until proven otherwise.

Supplements

 

• Dietary additions that are not required to undergo testing before selling.
• Not allowed to claim treatment or cure of diseases.
• Ingredient labels do not have to be accurate.
• Supplements are considered safe until proven otherwise.

Here’s a great article about the regulations surrounding supplements.

Is Feeding Diatomaceous Earth Safe for Horses?

 

• Is DE safe for horses to eat? Yes. It’s already an ingredient in some horse supplements. And, it’s used in foods and medications. If you choose to feed straight diatomaceous earth, you must be 1000% certain of the purity of it.

• There are still many questions and things that science still needs to study. One day, we’ll get there!

 

Fecal egg counts test for the presence of intestinal parasites and determine what dewormers are best. 

 

The Science About Diatomaceous Earth for Horses

 

• There are some studies that both negate and may support using DE in your horse’s diet. Let’s go through them.

The big study at Texas A&M

 

• Texas A&M University concluded a study in which 37 (!!!) horses participated, testing DE as a dewormer. You can read the study here, pointing out that DE could be effective as a dewormer in some ruminants. But, for horses, this is the conclusion:

“Diatomaceous Earth The data collected from the six week DE study indicated that DE has no significant effect on intestinal parasite burden of equine. Figure 4 reveals no difference in residual egg counts ANTHELMINTIC RESISTANCE AND EFFICACY OF DIATOMACEOUS EARTH IN EQUINE 21 between the treatment and the control group over the six week trial period. Figure 3 indicates that individuals with a higher initial egg count tended to have higher egg counts throughout the study than those individuals that had lower initial egg counts. Since there was no significant difference seen between the FEC of individuals that received DE and those that did not it can be said that DE is not effective as an anthelmintic and should not be used as such.”

DE as insecticide on crops

 

• This study, while not directly equine-related, looked at the effectiveness of diatomaceous earth formulations against insect larvae of crops. Depending on the formula, they eliminated 34% to 100% of larvae. This result happened outside of a digestive system and ensured contact between DE and bugs.

You can read the abstract here.

 

The big review

 

• Some very enterprising scientists conducted a comprehensive review of alternative deworming methods for sheep and goats, and hidden deep in the paper on page 79 are the findings of one study about diatomaceous earth in sheep and goats:

“One in vivo trial could be found, which showed no de-worming effect.”

You can read this review here.

 

Sheep and goats – inconclusive results

 

• A UK study looked at sheep and goat, and found concluded with this vague statement:

“Inclusion of a specific type of diatomaceous earth in the diet of grazing ruminants may offer some benefits in controlling internal parasites, however longer term studies are required to determine optimal quantities and duration of inclusion.”

Read this study here.

 

A study about rabbits and DE

 

• One researcher in Zambia fed rabbits DE and noticed that their coats looked better and their droppings were drier, contributing to cleaner pens and fewer flies.

You can read this summary here.

 

 

A veterinarian shares their thoughts about parasites and DE

 

• Equus magazine published an article about diatomaceous earth and horses, and the vet summarized that DE is ineffective in horses. They state:

“Because these are marketed as feed supplements rather than medicine, they need to prove only that they are safe—they do not have to show that they actually work. And, in fact, very few of them offer supporting data documenting any antiparasitic effect. When parasitologists have tested some of these products, they have rarely found convincing results.”

Read the article here.

 

Diatomaceous Earth and Horses – a Summary

 

• Here are many reasons why diatomaceous earth for horses is not believed to be an effective antihelminthic, and it’s clear that the most significant risk to relying on DE as a substitute for fecal egg counts and deworming is the uncertainty of side effects.

Water – you must add water to the diatomaceous earth to safely feed it to your horse, and we know that water decreases the effectiveness of DE against the exoskeletons of insects.

Digestive system – If diatomaceous earth were effective against internal equine parasites, it would also damage the horse’s intestinal lining.

Volume – The volume of forage, feeds, water, digestive enzymes, and everything that a horse digests wildly out-volumes the diatomaceous earth in your horse’s feed. There is a minuscule chance that any DE would contact intestinal worms.

Larvae are already weirdly strong – Part of the parasite life cycle includes surviving teeth, saliva, stomach acids, and the digestive process as a whole. Is it likely that one, diatomaceous earth could come into contact with them, and two, that the WET DE could do anything at that point?

Soil and sand – Your horse already eats sand, which doesn’t weaken when wet and doesn’t act like an antihelminthic.

 

Picking manure from pastures contributes to a reduction of larvae in the environment. 

 

The Unknowns

 

• You need to find out how much crystalline silica is in the formula you buy – Can you trust the company that makes the DE? It’s unregulated. Many supplement companies are excellent at providing independent research, can show proven track records, and adhere to the best manufacturing and sourcing procedures. Some companies are simply good at marketing.

• Could diatomaceous earth create more digestive issues? Maybe? Can those tiny diatoms affect the cell walls of the microbes in the hindgut? What about making ulcers worse?

• Minerals, like magnesium, calcium, and trace minerals are abundant in diatomaceous earth, and may benefit your horse’s overall nutrition, and some claim hoof health as well. An equine nutritionist can help you determine the best balance of vitamins and minerals in your horse’s diet to avoid overlapping products.

• There is no clear and scientifically backed dose of DE for horses. Perhaps one day they can master email and send us a message about how much they need!

What are the proven methods for effectively deworming horses?

 

Parasite control is part of equine health care, and it’s always best to partner with your vet. Use fecal egg counts to uncover your horse’s worm count, and have your vet evaluate the results. Your horse may not need a dewormer at all, and if they do, your vet can give you the best one. It will depend on your horse, where you live, and the time of year.

 

How often should a horse be dewormed?

 

The standard practice recommended by the American Association of Equine Practitioners (AAEP) is to perform fecal egg counts in the spring and fall and deworming as necessary with appropriate medications. Diatomaceous earth for horses is unproven as a dewormer.

 

Are zeolites the same as diatomaceous earth?

 

Zeolites and diatomaceous earth are both natural substances. While DE is the fossils of diatoms, ancient aquatic organisms, and zeolites are aluminum silicate crystals that can be made in the lab or found naturally. There is also zero carcinogenic risk with zeolites, which absorb urine and manure odors in wet stalls.