Liver fluke in cattle and sheep: getting ahead of a rapidly adapting parasite

Abstract

Background: Liver fluke has a significant impact on the beef, dairy and sheep sectors in terms of disease and production losses, and thus also greenhouse gas emissions. The challenges in managing liver fluke are similar to those for other endoparasites of cattle and sheep, with the threat of resistance to some available actives and a need to focus on the ‘whole farm’ approach. This includes avoiding the challenge where possible and using the right treatment at the right time, by using the available diagnostic tests appropriately. Changes in climate and environmental conditions have led to changes in when snails are active, and therefore when infections are acquired. Treatments based on a set of assumptions as to when immature/adult fluke will be present in cattle and sheep are now likely to lead to unnecessary treatments and incorrect timing of treatment with actives, which may not be effective for the age of fluke in the liver at the time. Timing of treatment will vary on the same farm each year and between farms in the same year. Understanding the life cycle, snail habitats, diagnostic tests and treatments will allow better fluke control in herds and flocks.Aim of the article: This article aims to shift the emphasis from treatments as the main method for control towards other critical control points relating to the mud snail's role as the intermediate host. This will allow an appreciation of risk periods for acquiring, avoiding and detecting infection within the ruminant host.