Sheep have long been recognised to suffer from liver fluke, with both acute and chronic forms being recognised. Fluke is also on the rise in cattle where the sub-clinical form of the disease is more often identified during routine herd health visits by vets carrying out faecal eggs counts or blood tests. As cattle can develop partial immunity to fluke, they can act as a source of infection for sheep flocks, as can other wildlife such as deer. Increasingly vets and farmers are reporting anaemic sheep suffering ill thrift in areas where fluke has never been endemic, which are subsequently diagnosed with fascioliasis.
Newer approaches to the challenge fluke control represents concentrate on strategic approaches – using the right products at the right time – and rotating products more effectively. Spring/summer treatments with closantel are being increasing advocated as a means to reduce pasture contamination with fluke eggs. Closantel (Flukiver®) disrupts egg laying and the viability of eggs for 13 weeks – longer than any other flukicide. As there are no early immature fluke in the host at this time of the year their eradication should not be the end goal of treatment. By reducing the pasture burden the autumn challenge is reduced, which means that by the time tupping comes around, the flock could be in much better shape. Another benefit of closantel is the six week protection it gives against Haemonchus or ‘Barber’s Pole’ worm, which is another serious parasite on the increase.
This article was published in Cornwall Farmer’s Newsletter in 2009.
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