Sheep Lice and External Parasite Welfare

Sheep lice cause intense pruritus and welfare distress in affected flocks, with appropriate biosecurity and treatment providing effective prevention and control.

Key Facts

Bovicola ovis, the sheep biting louse, affects an estimated 30-40% of UK flocks
Infested sheep show intense rubbing, wool damage, and weight loss from feeding disruption
Lice spread most rapidly in housed flocks during winter where sheep are in close contact
Preventive pour-on treatments at housing or purchase of new stock prevent most infestations
Resistance to synthetic pyrethroid treatments is emerging in some sheep louse populations

Welfare Considerations

Sheep lice cause chronic discomfort through intense itching that disrupts normal feeding, rest, and social behaviour. Infested sheep rub and bite continuously, damaging wool and causing skin abrasion. The chronic nature of the condition - infestations can persist for an entire winter season without treatment - means significant prolonged suffering affects a substantial proportion of UK sheep annually. Prevention through appropriate biosecurity and treatment at housing is straightforward and highly effective.

What You Can Do

Support farms that implement preventive lice treatment at housing
Advocate for external parasite control to be included in sheep welfare audits
Support research into sustainable parasite control as resistance emerges
Choose lamb from farms with documented parasite management programmes
Engage with farm assurance schemes about external parasite welfare requirements