Livestock farmers face an ongoing challenge: controlling invertebrate parasites such as flies, grubs, worms, and ticks that harm animal health and productivity.
These pests can transmit disease, reduce performance, and even kill animals in severe infestations. Managing them effectively is crucial not only for animal welfare but also for economic sustainability.
The High Cost of Parasitic Pests
The economic toll of livestock parasites in the U.S. is staggering. Each year, flies cause an estimated $9.6 billion in losses, parasitic worms (helminths) another $8.5 billion, and ticks approximately $636 million.
These figures reflect reduced weight gain, lower milk yields, and higher veterinary costs. To mitigate these losses, farmers often rely on chemical parasiticides.
The Hidden Cost of Chemical Control
While parasiticides protect livestock, they can also harm beneficial insects that naturally reduce pest populations. Among the most affected are dung beetles, which play a vital role in farm ecosystems.
Their decline can disrupt soil health, increase greenhouse gas emissions, and reduce natural pest suppression—ironically making future parasite problems worse.
Nature’s Unsung Allies
Predatory beetles—members of families such as Carabidae, Histeridae, Hydrophilidae, and Staphylinidae—feed on pest larvae found in dung. Meanwhile, dung beetles from the Scarabaeidae family quickly bury manure, mixing nutrients into the soil and cutting methane emissions.
In as little as one week, they can recycle a dung patty entirely, improving both soil fertility and pasture quality.
A Win-Win for Integrated Pest Management
Farmers who use Integrated Pest Management (IPM) practices benefit from supporting these insects. By maintaining healthy dung beetle populations, they can reduce reliance on chemical treatments and improve soil and climate resilience.
But the key question remains: which antiparasite products harm these beneficial beetles—and which are safe to use?
Testing Three Common Parasiticides
Researchers at West Virginia University set out to answer that question. Their study, published in Environmental Entomology in July, examined the effects of three widely used parasiticides—Clarifly (diflubenzuron, used for fly control), LongRange (eprinomectin, targeting worms, mites, and grubs), and Safeguard (fenbendazole, for helminths)—on dung beetles living in cattle pastures.
Tracking Residues in Cattle Feces
The research team, led by graduate student Haylie Brown, first evaluated how long residues of each product persisted in cattle feces. They divided cattle into four treatment groups: Clarifly, LongRange, Safeguard, and an untreated control.
Over 150 days, the team collected and analyzed fecal samples using high-performance liquid chromatography to measure chemical concentrations.
Testing Beetle Responses
Next, the team assessed beetle responses in a controlled experiment. They collected untreated dung from a separate farm and mixed it with varying doses of each parasiticide—ranging from 0.05 milligrams per kilogram (mg/kg) for LongRange to 10 mg/kg for Safeguard.
The goal was to simulate realistic exposure levels that beetles would encounter in the field.
Persistence and Toxicity
Results showed that Safeguard residues disappeared within three days, posing minimal risk to dung beetles. In contrast, Clarifly and LongRange remained active for 8–12 weeks after treatment.
Dung treated with LongRange proved toxic to dung beetles for 30 to 90 days, while Clarifly also reduced beetle abundance during the testing period.
The Good News: Not All Beetles Affected
Interestingly, none of the parasiticides—Clarifly, LongRange, or Safeguard—had significant effects on other predatory beetle species. This finding suggests that some beneficial insects may be more resilient to these compounds.
However, for dung beetles specifically, the long-lasting residues from certain treatments can disrupt entire populations.
Safeguard Emerges as the Safe Choice
“Even at the highest tested concentration of 10 mg/kg, we found no decline in Scarabaeidae,” says Brown. “We do not recommend any changes to the current use of Safeguard and advise that it be applied according to the manufacturer’s label.”
Safeguard’s quick excretion makes it a safer option for farms that depend on dung beetle activity.
Clarifly and LongRange Raise Concerns
The researchers caution against prolonged or “long-acting” parasiticides like Clarifly and LongRange. Their persistence in feces can negatively impact dung beetle populations and, over time, hinder the natural breakdown of manure.
Farmers using IPM systems should consider these effects before applying treatments designed for long-term control.
Balancing Animal Health and Ecosystem Health
While farmers can adjust timing and dosage to minimize risk, the study’s authors recommend exploring alternative treatments for controlling flies, ticks, and grubs.
Choosing products that target pests while sparing beneficial insects ensures both effective parasite management and long-term farm sustainability—a win for livestock, soil, and the environment.
FAQs
Why are parasites a major concern for livestock farmers?
Invertebrate parasites such as flies, worms, ticks, and grubs can transmit disease, lower productivity, and even kill animals. They cost U.S. livestock producers billions each year through lost weight gain, reduced milk yield, and increased veterinary expenses.
How do dung beetles benefit livestock farms?
Dung beetles bury and recycle manure, improving soil health, reducing methane emissions, and suppressing pest fly populations. They also promote nutrient cycling, helping maintain pasture quality and overall ecosystem health—making them essential allies in integrated pest management (IPM).
Which antiparasitic products harm dung beetles?
The West Virginia University study found that Clarifly (diflubenzuron) and LongRange (eprinomectin) persist in cattle feces for 8–12 weeks and are toxic to dung beetles. These products reduce beetle abundance and activity, potentially disrupting natural manure decomposition on farms.
Which antiparasitic product is safe for dung beetles?
Safeguard (fenbendazole) showed no harmful effects on dung beetles, even at high concentrations. It is excreted within three days of treatment, minimizing environmental impact. Researchers recommend continuing its use following manufacturer guidelines.
How can farmers balance parasite control and ecosystem health?
Farmers should use Integrated Pest Management (IPM) practices—combining targeted parasite treatments with support for beneficial insects. Avoiding long-lasting parasiticides like Clarifly and LongRange, and timing treatments strategically, helps protect dung beetle populations while maintaining effective parasite control.
