Liver fluke warning as wormer resistance rises

Livestock producers should re-think their liver fluke programme to avoid an onslaught of the disease.

Speaking to the Farmers Weekly at the Livestock Event 2012 Cath Tudor, from ProStock vets, Carmarthen, said a change in weather patterns had resulted in a variation to the breeding period of liver fluke.

Traditionally livestock producers worm animals in the autumn months of October and November, during winter housing, to prevent liver fluke.

But Ms Tudor said wet conditions in the summer meant many producers might now need to consider worming earlier than this.

“Now, because the breeding season is extending we are seeing adult fluke this time of the year,” she explained.

She warned that sheep producers needed to be particularly proactive, with widespread resistance to the wormer Triclabendazole being reported.

“In sheep it [resistance] is causing a big problem, because many producers think they are treating them, but faeces egg counts are showing the same levels, if not higher post-worming.”

She said sheep farmers should keep monitoring for resistance by sampling faeces or getting feed-back on livers from their slaughterhouse.

Ideally, she said samples should be taken with three weeks of treatment to determine if the application has worked.

However she said it was difficult to give producers accurate advice on how often they should now be worming.

“Every farm is individual. Some will need to do it all year-rounds, while others may only need to do it every 7-8 weeks”

Instead she advised producers to speak with their vet to set up a bespoke control programme.


  • Sudden death in sheep

  • Scouring

  • Loose skin under the jaw, known as “bottle” jaw

  • Reduction in milk production in dairy cows

  • Loss of condition

  • Poor weight gain and performance

For more on this topic

See our Livestock 2012 page

Flukes and worms academy


Rhian Price on G+