How to manage Flystrike in your flock

For sheep farmers, the summer months mean one thing: the dreaded flystrike. This can be a devastating condition, causing immense suffering to the sheep and significant economic losses for farmers.

It is essential to understand the causes of flystrike. More importantly, knowing how to prevent and treat it is crucial for maintaining a healthy flock during the warmer months.

Flystrike, also called myiasis or blowfly strike, happens when adult flies – most commonly the green bottle fly (Lucilia sericata) – lay their eggs on sheep.

These eggs quickly hatch into maggots that feed on the sheep's flesh, releasing toxins. This causes irritation and inflammation, and without treatment, can rapidly lead to septicaemia, shock, and even death.

Flies are attracted to warm, moist, and soiled areas. Here are the primary culprits that make a sheep susceptible:

• Faecal Soiling (Dags): This is the biggest draw. Loose faeces, often due to diarrhoea or a rich diet, get matted in the wool around the rear end. This creates a perfect breeding ground – warm, moist, and a food source for the maggots once hatched.
• Open Wounds and Cuts: Any break in the skin, no matter how small, can attract flies. Shearing cuts, scratches from fences, or even abrasions from fighting can be entry points.
• Foot Rot and Other Infections: Oozing sores, particularly from foot rot, create a strong smell that attracts flies. Any damp, infected area on the sheep's body is an invitation.
• Urine Staining: Especially in rams or ewes with urinary incontinence, wet and stained wool provides another attractive site.
• Warm and Humid Weather: Summer provides the ideal conditions for blowfly activity. Warm temperatures accelerate the fly lifecycle, and humidity keeps the wool moist, aiding egg survival and maggot development.
• Dense Fleeces: Longer, denser fleeces, can trap moisture and heat, perfect conditions for maggots, especially around the tail and britch area.

Always conduct daily, close inspections of your flock during warm, humid weather. Early detection is key to preventing severe suffering and mortality.

Preventing flystrike is always better than cure when it comes to flystrike. Here's a multi-pronged approach to reduce the risk and enjoy a fly-strike-free summer:

• Crutching/Shearing: This is your first line of defence. Shearing the whole flock before the fly season starts is ideal. If full shearing isn't feasible, crutching (shearing around the tail, britch, and inner thighs) is essential. This removes soiled wool and exposes the skin to air, making it less attractive to flies.
• Dagging/Worm Control: Regularly check and remove dags. Effective worm control is vital to prevent diarrhoea, which is a major contributor to dag formation. Talk to your vet about a strategic worming programme.
• Pour-ons and Dips: There are various products available that provide long-lasting protection against flystrike. These typically contain insecticides that kill maggots or prevent eggs from hatching. Apply these products according to the manufacturer's instructions, paying close attention to withdrawal periods for meat and milk.
  Pour-ons: Applied down the backline, they spread through the fleece.
• Dips: Full immersion in an insecticidal solution. This offers excellent coverage but requires specialist equipment and careful disposal of the dip wash.
• Wound Management: Promptly treat any wounds or cuts on your sheep. Use antiseptic sprays and, if necessary, an insecticidal wound dressing.
• Footcare: Regular foot trimming and treatment of foot rot will reduce attractive odours and sites for flies to lay eggs.
• Breed Selection: Some sheep breeds with open fleeces or less wool around the britch area may be less susceptible to flystrike.
• Monitoring: Daily checks of your flock during the summer are crucial. Look for any signs of discomfort, dark patches on the wool, or sheep standing away from the rest of the flock.

If you discover a sheep with flystrike, immediate action is paramount.

• Isolate the Affected Sheep: This allows for easier and safer treatment.
• Clip the Affected Area: Carefully shear away the matted, maggot-infested wool. This exposes the maggots, allowing the treatment to penetrate effectively. Be gentle to avoid further skin damage.
• Apply a Larvicidal Treatment: Use a product specifically designed to kill maggots. These often come as a spray or pour-on. Ensure the product makes good contact with all the maggots.
• Clean the Wound: Once the maggots are dead, gently clean the underlying skin with a mild antiseptic solution.
• Monitor for Secondary Infections: Flystrike wounds are prone to bacterial infections. Your vet may recommend antibiotics if the wound is severe or infected.
• Pain Relief: The sheep will be in considerable pain. Discuss pain relief options with your veterinarian.
• Ongoing Monitoring: Keep a close eye on the treated sheep for several days to ensure no new maggots appear and the wound is healing.

Flystrike is an unpleasant reality of summer sheep farming, but with diligent prevention and swift action, you can protect your flock and prevent strike. Stay vigilant, stay proactive, and enjoy a healthy summer with your sheep!