Cypermethrin
Cypermethrin is a synthetic type II pyrethroid used in external parasite-control products. Veterinary formulations include species-specific pour-ons, sprays and dips for livestock. Applications cover selected ticks, lice and flies, including sheep blowfly-strike control. Isomer composition and delivery system influence the product’s parasite spectrum and persistence.
Group
Synthetic pyrethroid ectoparasiticide
Mechanism of Action
Cypermethrin prolongs activation of arthropod voltage-gated sodium channels and delays restoration of normal nerve-membrane potential. Repetitive neural excitation progresses to impaired coordination, paralysis and parasite death. Contact exposure at the skin or fleece surface provides ectoparasiticidal activity, with persistence determined partly by the formulation and surface distribution.
Dose Rates
Sheep
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| External parasite control | Reference only | TOPICAL | Use the exact Ectofly 12.5 mg/mL pour-on label for indication-specific weight/application tables and nozzle choice. This record does not supply a universal mL/kg or spray dilution. |
Indications
- Control of susceptible ticks, lice or biting flies in cattle, sheep or other product-supported livestock species.
- Prevention and treatment of blowfly strike in sheep using a corresponding product.
- Treatment or control of sheep headfly infestation with an indicated formulation.
Contraindications
- Do not apply livestock concentrates to cats.
- Use only the target species and dilution specified; prevent fish/aquatic exposure.
Interactions
- Concurrent insecticides may increase neurotoxicity.
Adverse effects
- Skin irritation, salivation, tremors and ataxia after excessive exposure or ingestion.
Toxicity
Remove contaminated product and provide supportive treatment for pyrethroid neurotoxicity; control tremors and temperature.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Ectofly pour-on 12.5 mg/mL High-cis 80:20 cypermethrin sheep pour-on; not an injectable or a ready-made dilution for other products. | Other | 12.5 mg / mL | TOPICAL |
Monitoring and Administration
Do not infer a systemic mg/kg dose from dip concentration. Application volume, nozzle, wool length and body area are integral to treatment.
Keep sheep away from watercourses after treatment as directed; cypermethrin is highly toxic to aquatic organisms.
Use gloves and avoid contaminating feed or drinking water.