Evaluating Essential Oil-based Formulations for the Alternative Control of Winter Cattle Lice

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Commodities

• Animals: bovine

Practices

• Animal Production: animal protection and health, housing, parasite control
• Pest Management: botanical pesticides, integrated pest management
• Production Systems: organic agriculture

Lice infestations during winter housing represent a significant challenge for cattle producers, particularly organic operations raising cattle without chemical inputs. Clinical disease may be prevented using conventional insecticides, but there are growing concerns over the development of resistance and negative environmental impacts. Farmers in the Northeast have expressed the need for effective alternative control strategies during winter when louse populations negatively impact animal health and production. Essential oils as botanical insecticides have been shown to significantly reduce louse numbers as a grooming aid in donkeys, however impracticalities of regularly reapplying treatments and achieving coat penetration have been a barrier to their use in livestock.

This project addresses these challenges by co-developing essential oil-based formulations in partnership with VT farmers and trialing them in a cattle self-groomer/scratcher oil-dispenser. These are usually used with chemical insecticides or inert mineral oils but represent a novel route of administration for essential oil insecticides. In year 1, essential oils of known efficacy against lice will be selected and tested in laboratory trials. In year 2, a final formulation resulting in ≥90% louse mortality in the lab will be tested through on-farm trials with cattle. The self-groomer/scratcher will provide a time and labor-saving technique where animals self-administer formulations and achieve coat penetration through the scratching brushes. Summer workshops, field-days, webinars, and factsheets will introduce and demonstrate lice management and the essential oil formulations. These new tools will be particularly useful in the Northeast against problematic seasonal infestations when cattle are housed for long periods over winter.

This project will develop and test essential oil-based formulations for the control of winter cattle lice.

Objective 1: Identify essential oils of known insecticidal activity against lice, and carrier oils already approved for organic cattle production. Essential oils will be evaluated for suitability with partner farmers, show high louse mortality at low concentrations, and be safe to apply to cattle based on previous literature and safety data.

Objective 2: Test the efficacy of combinations of essential oils and carrier oils against lice and eggs in the laboratory using contact and vapor bioassays. The final formulation developed for the field trial (objective 3) will show ≥90% louse mortality at a concentration of ≤10%.

Objective 3: Test the efficacy of the formulation against lice in an on-farm field-trial using the self-groomer/scratcher oil-dispenser. Cattle will be housed in two groups to compare the impact of the essential oil formulation against the carrier oil control.

Impact: The results will demonstrate the efficacy of a new tool for farmers to control cattle lice using a time and labor-saving application technique, for use across diverse management systems. Reduced economic, environmental, animal health burden of winter cattle lice in the Northeast and increased confidence for farmers