How are sheep treated for fleas? - briefly
Sheep are usually treated with topical insecticides—pyrethroids, organophosphates, or pour‑on formulations—applied along the back, while systemic options such as ivermectin may also be administered. Treatments are repeated at intervals specified on the product label, often every two to four weeks during peak flea activity.
How are sheep treated for fleas? - in detail
Fleas on sheep are eliminated through a combination of chemical, biological, and management strategies. Effective control begins with accurate diagnosis: visual inspection of fleece, skin, and bedding for adult insects, larvae, or eggs, and observation of itching or restlessness. Once infestation is confirmed, the following measures are applied.
-
Topical insecticides – pour‑on preparations containing pyrethroids, organophosphates, or synthetic avermectins are applied along the backline. Recommended dosage ranges from 0.2 to 0.5 ml per kilogram of body weight, depending on the product label. Application must cover the entire spine to ensure contact with the skin and underlying fur.
-
Injectable avermectins – subcutaneous injection of ivermectin or moxidectin provides systemic protection. Standard dosing is 200 µg kg⁻¹ for ivermectin and 0.2 mg kg⁻¹ for moxidectin. Results appear within 24 hours and persist for up to four weeks, covering the life cycle of the parasite.
-
Oral formulations – flavored tablets or drenches containing doramectin or selamectin are offered to the flock. Dosage is typically 0.2 mg kg⁻¹, administered on a single day or repeated after a 14‑day interval to target emerging larvae.
-
Dipping and spraying – immersion in a bath of insecticidal solution (e.g., cypermethrin at 5 mg L⁻¹) or targeted spray of the fleece can be used for large groups. Dipping requires a minimum of 5 minutes of contact time; thorough rinsing follows to prevent residue buildup.
-
Environmental sanitation – regular removal of manure, replacement of bedding, and rotation of pastures interrupt the flea life cycle. Pasture rest periods of at least 30 days reduce larval survival in the soil.
-
Biological control – introduction of entomopathogenic nematodes (e.g., Steinernema spp.) into heavily infested paddocks can suppress larval populations. Application rates are 1 × 10⁸ infective juveniles per square meter, repeated every two weeks during peak activity.
Treatment schedules typically involve an initial therapeutic dose, followed by a second administration 10‑14 days later to eliminate newly hatched fleas. Monitoring after each treatment includes re‑inspection of a sample of animals and assessment of skin condition. Resistance management requires rotating classes of insecticides annually and avoiding repeated use of the same active ingredient.
Safety considerations include observing withdrawal periods for meat and milk, confirming that the selected product is approved for ovine use, and adjusting dosages for pregnant or lactating ewes. Proper handling of concentrated formulations prevents dermal exposure to personnel.
Combining chemical interventions with rigorous pasture management and regular health checks yields sustained reduction of flea burden in sheep flocks.