Blowfly strike (myiasis) is one of the most acute and painful welfare conditions affecting sheep in the UK and globally, causing significant suffering that is largely preventable with appropriate management.
Blowfly strike causes severe pain as maggots feed on living tissue, producing toxic secretions that cause local and systemic illness. Affected sheep become lethargic, isolate from the flock, and show classic pain behaviors. Without rapid treatment, strike progresses rapidly to cause deep tissue damage and septicemia. Farmers who do not regularly inspect their flocks may not identify strike until advanced stages. The paradox of mulesing - causing acute short-term pain through surgery to prevent chronic strike risk - illustrates the complex welfare trade-offs in sheep management. Non-mulesing alternatives are improving but not yet universally adopted.