HCC Report Reveals “Worrying” Wormer Resistance Levels

Resistance to worm drenches to combat parasitic diseases continue to build and Welsh farmers need to take measures to immediately rectify existing practices or the industry faces serious consequences in the future, an industry research project has revealed.

The stark conclusions of Hybu Cig Cymru – Meat Promotion Wales’ (HCC) investigation into resistance to wormers for eliminating parasitic diseases in sheep are “worrying but its not too late to act,” said Lynfa Davies, HCC’s Technical Development Executive. “HCC is now leading a pan-industry awareness campaign to drive home to farmers that changes have to be made if flock health is not to seriously suffer in the not-too-distant future.” 

Mrs. Davies explained: “Anthelmintic resistance means that a wormer loses effectiveness because a proportion of the worms survive treatment. This is an important issue and will affect the sustainability of the sheep industry in Wales if not taken seriously.

“It is worrying and a serious wake-up call because it is now really essential that farmers know which wormers work on their farm. If they use ineffective treatments, the overall health status of their flock will deteriorate and a huge amount of time, effort and money will be wasted,” said Mrs. Davies.

The project ran from September 2014 – July 2015. It was funded through the Rural Development Plan for Wales 2007 – 13 and overseen by HCC. It looked at 47 Welsh farms and the effectiveness of four types of wormer: Benzimidazole (1-BZ); Levamisole (2-LV); Ivermectin (3-ML) and Moxidectin (3-ML).

It revealed:

·       One farm only showed that all drugs were still fully effective on that farm;

·       94% of farms have evidence of resistance to Benzimidazole;

·       68% of farms have evidence of resistance to Levamisole;

·       51% of farms have evidence of resistance to Ivermectin;

·       19% of farms have evidence of resistance to Moxidectin.

Apart from the single farm that was considered fully effective, all other farms had resistance to one or more of the anthelmintic classes and as many as 43% of farms showed resistance to either three or four of the different classes of anthelmintic.

“These results show a significant rise in resistance levels compared to the previous study undertaken in 2006, when 78% were resistant to Benzimidazole, 34% were resistant to Levamisole and resistance to the other two wormers was considered to be low,” said Mrs. Davies.

HCC presented the report’s findings to the UK’s Sustainable Control of Parasites in Sheep  (SCOPS) Committee last Thursday (24 September) with the aim of developing a best course of action for farmers alongside a communications and knowledge transfer strategy to empower as much of the industry as possible with this information.

SCOPS is an industry led group that focuses on informing farmers and the wider industry on the best practices to slow the development of anthelmintic resistance and preserve the active ingredients available to farmers for as long as possible.

“The report demonstrates that there were some positive outcomes,” said Mrs. Davies. “The one farm that had no resistance evident had followed SCOPS guidelines - demonstrating how important it is for farmers to heed the advice given by SCOPS.”

Welsh farmers wanting more information should contact HCC www.hccmpw.org.uk or SCOPS www.scops.org.uk