Blanket use of wormers ahead of lambing ‘can add to risks’

While the widely adopted practice of worming ewes in the run-up to lambing has long been viewed as good practice, new research published this week has contradicted this approach.

And, rather than protecting both ewes and lambs, scientists now believe that such a blanket use of anthelmintics could be putting both at risk of a build-up of resistant worms.

A three-year project carried out by the Animal Plant and Health Agency (AHPA) and funded by the Veterinary Medicines Directorate (VMD) published this week found no advantage in blanket worming ewes at lambing. 0 Routine worming of ewes can harm mother and lamb

Faecal egg counts from lambs reared on ewes that were wormed with either a short-acting or long-acting wormer were found to be no lower than those from ewes which had not been treated.

Jane Learmount, lead research on the project, said: “Over-use of anthelmintics is a major factor in the development of resistance, and treating adult sheep unnecessarily only adds to the problem.” Commenting on the study which had looked at worm levels on 16 commercial farms she said: “The bottom line is that we could not demonstrate any clear benefit in terms of worm infection levels in lambs as a result of worming ewes on the farms studied.”

Learmount said that the research supported the sustainable control of parasites in sheep recommendation to use a targeted approach to the administration of wormers on sheep farms, including leaving the fittest ewes untreated around lambing.