Blowfly strike in the breech region of sheep in relation to helminth infection

The incidence of breech strike in radically mulesed weaner sheep was reduced from about 50% to about 5% by suppression of helminth infection. Prediposition of sheep to flystrike appeared to result from the helminths causing diarrhoea and soiling of the wool in the breech region. Wethers were struck more frequently than ewes. The efficiency of control of breech strike in mulesed weaners is considered in relation to helminth control and crutching.