Chemical vs. Natural DEVELOPMENT

(By Dr. Frauke Garbers, Biologist)

To this day, horse owners are driven crazy by the alleged dangers of worms and use the resulting panic to force them to use chemical wormers on a regular basis.

Chemical dewormers are drugs that require a prescription and therefore can only be dispensed by a veterinarian. Medications they are because they can have significant side effects. In principle, the use of drugs is only allowed if a diagnosis has been made beforehand. This also applies, for example, to antibiotics, which may only be used after an exact determination of the pathogens.

Diagnosis regarding worms means: A fecal examination is required and the number of worm nuclei per gram of feces must be counted. Only when the load is greater than 200 to 250 eggs per gram of feces should chemical deworming be used.

Deworming horses naturally

It is much better to use herbs to change the environment in the intestine and at the same time strengthen the immune system so that ingested larvae in the intestine cannot develop into worms in the first place and worms feel so uncomfortable that they leave with the feces.   

Horse owners have been persuaded that there is an inevitability of worming if even one horse in the herd is burdened with worms. Now there is probably no horse that does not harbor some worms. From this was then derived the obligation to deworm all horses several times a year. A fantastic business concept, mostly justified by the fact that the worming treatments are completely harmless. Many of you know better.

You also have to ask yourself how horses coped with worms in earlier centuries. There were umpteen times more horses than today. There were droppings on every street and the possibility of getting infected with larvae was extremely high. And what did people do back then? They fed their horses according to the species. Many herbs grew on meadows and along meadows, which strengthened the organism and protected it from strong worming.

Classic deworming schedule for horses (worming)

Adult horses prophylactically 4 times a year, in case of poor hygiene or stables with frequent change of horses 5 times a year. Foals are dewormed in case of infestation with the dwarf threadworm (Strongylide) in the 2nd week of life, in the further course every 14 days until the 8th week of life. In the case of roundworm infestation (ascarids), treatment begins at 1.5 to 2 months of age and continues at these same intervals until weaning. Mares should be given an ivermectin worming treatment on the day of foaling to reduce larvae in the mare's milk.  

These deworming measures reveal fear and insecurity, unthinking actions, and a lack of confidence in the body's natural ability to self-regulate. From experience, weakened immune systems lead to more severe worm infestation, for example in sick or weak animals, animals in poor husbandry or in critical phases of life (separation from the mother). Consequently, the immune system should be strengthened. The intestine must be rehabilitated and built up! Instead, the opposite happens - more frequent deworming, higher doses. The intestinal flora of the animal is destroyed with every chemical worming just like with an antibiotic! The community of microorganisms must be regenerated afterwards. Who knows this, makes this effort and acts accordingly? The fewest veterinarians enlighten here ... Probably they do not know it, have not thought about the topic of coevolution.

An unstable intestine weakens the defense system. Allergies and autoimmune diseases may be opened the door. Nowadays, there is no question of the horses, dogs and cats being in good health. The number of sickly animals has increased enormously - in relation to the intensive use of vaccinations, antibiotics, Antimycotica, Anthelminthika (worming means) and not kind-fair feed.

An unstable intestine weakens the defense system. Allergies and autoimmune diseases may be opened the door. Nowadays, there is no question of the horses, dogs and cats being in good health. The number of sickly animals has increased enormously - in relation to the intensive use of vaccinations, antibiotics, Antimycotica, Anthelminthika (worming means) and not kind-fair feed.


The frequent use of deworming drugs is the cause of the emergence of resistance, as well as the often indiscriminate use of deworming drugs. Also the dosage of the anthelmintic not correctly adjusted to the body weight leads to resistances (underdosing due to wrong weight estimation). At the end of the 1980s, recommendations were made to treat as little as possible with deworming drugs - in order to slow down the development of resistance.  

The resistance of worms to thiabendazole was already known 50 years ago (!). Since then, there has been widespread resistance worldwide to benzimidazoles, which were originally effective against small strongylids (bloodworms). This resistance applies to at least 13 species of small strongylids. As early as the late 1980s, multiple resistances of the small strongylids were suspected, e.g., to pyrantel (active ingredient in Banminth). Twenty years ago, there was already knowledge of ivermectin-resistant strongylids in small ruminants (sheep, goats) with fears of resistance developing in horses as well! "Moxidectin, which ... was initially still successfully used against the ivermectin-resistant strains of sheep nematodes, is, however, increasingly losing its efficacy there due to the development of side resistance...“ ( Moxidectin (a milbemycin) belongs to the macrocyclic lactone group with avermectins (e.g., ivermectin). Moxidectin and ivermectin show very close biochemical relationship with the same biological properties

10 to 15 years later: resistance of roundworms to ivermectin has also been reported in horses. The progression of resistance developments can apparently be watched ...

Common dewormers are e.g. Panacur (containing fenbendazole, i.e. benzimidazole), Banminth (containing pyrantel), Equimax (containing ivermectin), Equest (containing moxidectin). Obviously, nothing has been learned with regard to the development of resistance. On the contrary - people know about the resistances and continue to administer the agents. The dose is then increased and the frequency shortened. Example Equest, combination preparation praziquantel with moxidectin: About 20 years ago, the recommendation for praziquantel (against tapeworms) was 0.5 to 1 mg/kg body weight. Today's preparations contain concentrations of 2.5 mg/kg body weight, which is 2.5 to 5 times higher!

The effect decreases, the side effects increase with the amount and frequency of use. 

Toxicity of anthelmintics

The "side effects" can be: Diarrhea, increased salivation, labored breathing, ataxia, death.

Example of avermectins: these include the ivermectins and milbemycins. Their mode of action against nematodes is based on the activation of GABA (gamma-amino-butyric acid). This neurotransmitter plays a central role as a receptor in the CNS (central nervous system) of mammals and is involved, among other things, in motor control of the cerebellum. In nematodes (threadworms), GABA is found in neuronal and neuromuscular synapses (site of excitation transmission from nerve cells to other cells). GABA initiates the irreversible opening of chloride channels in muscle membranes: Transmission of nerve stimuli is interrupted, the worm is paralyzed, killed, and expelled by the host animal.

Avermectins have a toxic effect on the wormed host when they cross the blood-brain barrier and possibly accumulate in the CNS. Conflicting statements on this can be found in the literature:  

"Moreover, the intact blood-brain barrier in vertebrates (author's note) is hardly permeable for avermectins, but nevertheless an enhancement of GABA-ergic processes also occurs at neurons of the mammalian brain...", according to a 2011 dissertation from the University of Munich(

Since GABA is also present in the mammalian brain, binding to GABA receptors is also considered to be the cause of the toxic effects of avermectins..."(

"Avermectins are lipophilic (fat-loving) compounds, therefore "avermectins can diffuse through the membranes of any intact blood-brain barrier." ( -  - Cell membranes are largely composed of fat molecules!

 Completely unknown to producers, veterinarians and authorities cannot be the toxicity of dewormers: The spreading of appropriately contaminated horse manure or direct entry by the horse is prohibited by law in water protection areas! Avermectins and moxidectins poison fish and organisms living in water. Are you perhaps also concerned about the groundwater quality?

Alternative deworming options

How were wild horses able to balance with "their" worms for thousands of years? In any case, the wild horses did not get a quarterly worming treatment. Not even the horses from Dülmen!

Excursus: Selective deworming

Instead of prophylactic deworming, targeted, regular fecal testing: In this way, resistance pressure can be significantly reduced. Only at EpG values (eggs per gram of feces) of approx. 200 -250 is it assumed that the animal is more heavily wormed. However, limits up to 300 EpG are also given in the literature. "The EpG should be high enough that at this level infection still leads to the development of immunity, but low enough to keep the risk of disease and environmental contamination low (Uhlinger, 1993)." (

 So - don't get hung up on a few eggs, but exercise composure and don't react to blanket diagnoses without counting the eggs.

In the countries of Denmark, Sweden, Finland, Holland and Italy, the prophylactic use of dewormers is prohibited. There is an obligation to prove the existence of worm infestation before any chemical worming treatment.

Nature offers a variety of ways to keep worms in the intestine at bay. Until a few decades ago, horses, dogs and cats were dewormed in a "natural" way. Chemical dewormers did not exist. Dogs and cats were fed pieces of fur. Because everything that scratches, worms do not like (hair, rosehip seeds, coconut shavings, pumpkin seeds, walnut leaves). Horses were fed plants with vermifuge effect, e.g. horseradish or tansy. Also 2%-ige Propolis (bee kittharz) suspension over several days administered is successfully against worms to work.

A prerequisite for a lasting worm-repellent intestinal environment is the stabilization of the intestinal mucosa, e.g. by supplementary feeding of herbs, especially bitter herbs. This strengthens the defenses of horses, dogs and cats - endoparasites feel uncomfortable in this environment and migrate. Nowadays one-sided feeding requires supplementation with herbs

You see: Strategies for sensible worm control exist, reliable and practicable ones. You just have to want to...


Source and original texts:

By Dr. Frauke Garbers, Biologist

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