This article is for support only. It is not intended to diagnose, treat, cure, prevent or mitigate any disease.
Shari Frederick of the Holistic Horse, in her article, Wormers, Toxic Reaction and Natural Alternatives, said, "Today's horses are experiencing extremely adverse side effects to chemical wormers at an alarming rate!" Ranging from mild to severe, stress reactions within one hour of chemical worming may include: Loss of control-resulting in the horse dropping to the ground, tongue hanging from mouth accompanied by drooling, swollen neck, puffy lips and tongue, noticeably red gum burns, colic, allergic reactions, laminitis, various gut disturbances, and skin reactions, including bald patches. Most visible problems appear to subside within an hour.
Chemical deworming, especially over-worming, can damage the immune system of your horse. Life threatening internal damage can result from worm infestation, yet regularly compromising your horses immune system can be more harmful than the worms. Drugs and chemicals are breeding stronger enemies and can lead to toxicity. Often parasite-infested horses are the ones who are dewormed most frequently! They are less likely to fend off parasites as time goes on because they can't build their own defenses. Interestingly, the practice of regular deworming didn't begin until the 1960s. In the 1980s worming was only an occasional support. Chemical wormers alter your horses intestinal environment. Use a probiotic one week before and after worming to maintain healthy bacteria, and administer wormers with feed to minimize gut issues. Chemical wormers contain neurotoxins that target various worms. For more optimum results target both the adult worm and larvae. Any class of anthelmintic (medication causing the evacuation of specific worms), once resistant to a de-wormer, will indefinitely be ineffective.
Toxicity levels of wormers are continually being raised to cope with resistant worms: Raising toxicity levels in wormers hastens the development of worm resistance and exposes horses to unnecessary toxic chemicals. Synthetic wormers actually poison worms and protozoa, and at the same time overstress the liver and kidneys, forced to filter the poisons. Long-term exposure to these toxins can actually shut down organs! The greater the toxicity levels of chemical wormers, the greater the risk of overdosing.
Fecal test every three months. Worms may go undetected because they are rarely seen in the manure. If you have the lab count the number and types of parasite eggs, the degree of infestation can be determined. A false negative (a zero egg count) can result if the parasites are not actively releasing eggs or are in the small intestine, liver, heart or lungs (migrating through the body). The worms may be too sick to lay eggs, butnot die. Smaller species? eggs might even be broken down by digestion. Some may simply continue to migrate through tissues until they finally die. The encysted stages of a small red worm will not show up on a fecal test. Regular re-testing will more accurately determine worm presence, as will clinical signs. Better safe than sorry? Not every horse in the barn needs worming at the same time. Each horse needs to be tested. Variance in worm testing within a herd is the perfect example of how routine chemical worming can be an unnecessary toxic burden on horses.