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Fly-Free Management for Horses

Practical Tips and Repellent Insights from NAF 

Flies are a common nuisance during warmer months and can cause discomfort, skin irritation, and behavioural issues in horses. Among the many types of flying insects, horse owners are most concerned with the horse fly, but others also pose significant problems and require targeted management strategies.

Common Fly Types and Their Behaviours

  • Black Flies: These seek out areas with minimal hair, such as inside the ears, and feed on blood. They are present throughout the warmer months.
  • Midges: Active at dawn and dusk. Their bite introduces saliva into the skin, often triggering an itching response.
  • Crab Flies: Wingless insects that settle between the hindlegs. They do not fly and must be physically removed.
  • Stable Flies: Breed in muck heaps and commonly gather around the face and eyes. They appear around the same time as horse flies.
  • Horse Flies: Capable of cutting through the skin, resulting in larger lesions and potential allergic reactions.

Understanding Fly Repellents and Safety Regulations

All fly repellents marketed in the UK must be registered under Biocide and Pesticide regulations, carrying a valid HSE number on their label. This certification ensures that the product’s active ingredients have been tested for both safety and efficacy.

  • Essential Oils & Home Remedies: Often unregulated and can cause adverse reactions depending on concentration and formulation. Always exercise caution.
  • Unregistered Products: Avoid using products without an HSE number, as their safety and effectiveness cannot be guaranteed.

Active Ingredients in Fly Repellents

  • DEET (N,N-Diethyl-meta-toluamide): A synthetic compound originally developed by the U.S. military. It confuses insect receptors, making it difficult for flies to land. Use only equine-formulated versions. Patch testing is recommended. Effective for 6–8 hours.
  • Eucalyptus Citriodora Oil: A naturally derived ingredient with insect-repelling properties. Known to disrupt the odour receptors of flies. Often has a citrus or lemon scent.
  • Permethrin & Cypermethrin: Synthetic neurotoxins that kill insects by targeting the nervous system. While common in the U.S., they are not approved for topical equine use in the UK except under specific veterinary guidance. Toxic to cats and aquatic life; use with caution.
  • Citronella Oil: Traditionally used to deter insects, but cannot be legally marketed as a fly repellent due to regulatory restrictions. However, it is safe for competition use, including under FEI rules.

Fly Management Tips

  • Avoid turnout near standing water.
  • Turn horses out during cooler parts of the day or provide shelter from peak sun or midge-active hours.
  • Use only registered fly repellents and follow label instructions.
  • Keep stables clean and manage muck heaps to prevent fly breeding.
  • Poo picking supports pasture hygiene and reduces fly populations.
  • Fly rugs offer physical protection; repellents can be applied over the rug.
  • Wash off sweat and stable stains regularly, as flies are attracted to the scent.
  • Consider gels as an alternative to sprays for horses sensitive to mist applicators.

Environmental Considerations

  • Warm weather increases fly breeding and extends life cycles from spring through autumn.
  • Artificial lighting attracts flies at night—avoid positioning lights near stable doors.
  • Clean feed bowls thoroughly, as leftover food can attract insects.
  • Use stabling or field shelters during peak midge activity (dawn/dusk).

Applying a quality, long-lasting repellent (effective for up to 6–8 hours) is essential for creating an inhospitable environment for flies. Always ensure the product is legally approved, appropriately applied, and monitored for any adverse reactions.

Ask the experts

For more information on NAF Off products, or to speak to our team offering free nutritional advice tailored to your horse or pony, contact our Nutritional Advice Line – Monday to Friday, 09:00–17:00 (GMT):

📧 Email: info@naf-uk.com
📞 Phone: 0800 373 106
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