A farmer uses a wormer on a sheep© Mint Images/REX/Shutterstock

Resistance to wormers will continue to rise if people abuse products, says a leading parasite expert. 

Dave Bartley, from the Moredun Institute, issued the stark message as some regions of the country draw close to 100% resistance to some wormer products.

Dr Bartley added resistance developing in newer wormer products could jeopardise the development of drugs in the future.

“If the effectiveness of the newer group four orange and group five purple anthelmintics is lost to resistance issues, we are in trouble,” he said.

See also: Dual active wormer now available from ag merchants

“Companies are less likely to develop new worming products if they are then used inappropriately and resistance develops quickly, as they will be unable to recoup the cost of development in sales.”

He stated the Sustainable Control of Parasites in Sheep initiative has “made an impact” but change on anthelmintic use is still needed.

Four-pronged approach to anthelmintic resistance

Moredun Institute’s Dave Bartley suggested four elements, which combined approach could help the livestock industry address anthelmintic resistance:

  1. Faecal egg counts (FEC), condition scoring and testing Treat the animals most likely to be suffering from infections
  2. Catering for seasonality and weather fluctuations Timing application of drenches appropriately rather than operating to a fixed timetable
  3. Reading the label Avoiding use of anthelmintics for purposes other than worming
  4. Follow guidelines from the Sustainable Control of Parasites in Sheep initiative Taking other measures to reduce overall usage of anthelmintics