Liver fluke is a parasitic disease causing significant welfare harm in cattle and sheep across temperate regions, with climate change expanding its geographic range.
Liver fluke disease causes significant suffering across a spectrum from acute death to chronic wasting. Acute fasciolosis in sheep and occasionally cattle causes sudden death from massive liver hemorrhage following massive immature fluke migration. Chronic disease causes months of progressive deterioration with weight loss, weakness, and the discomfort of edema from protein loss. Bottle jaw, the edema of the jaw from protein deficiency, indicates advanced disease with significant welfare impact. The parasitic liver damage is painful and progressive. Prevention through strategic anthelmintic treatment timed to transmission risk is highly effective and far preferable to treating established disease.