External parasites including sheep scab, lice, keds and blow flies cause significant welfare harm in sheep, requiring integrated management approaches that balance efficacy with chemical stewardship.
Ectoparasite infestation causes welfare harm through intense itching, self-trauma, secondary infection and, in severe cases, systemic deterioration. Sheep scab in particular causes animals to bite and rub themselves raw, losing condition rapidly. Integrated management that combines monitoring, appropriate treatment and prevention of reinfestation protects sheep from these welfare harms while supporting chemical stewardship.