Welsh Anthelmintic Resistance Status Project

How well is your wormer working? Test don’t guess!

Testing for anthelmintic resistance is a vital part of any sheep health plan. Internal parasites are one of the most common and important diseases that livestock farmers have to deal with on a daily basis. It has been widely reported that resistance in wormers used for sheep is now widespread, with a 2015 study finding 60% of farms having resistance at some levels to all three of the common wormer groups (1BZ, 2LV, 3ML).  
Farming Connect has launched the Welsh Anthelmintic Resistance Status (WARS) project working with 40 Welsh flocks to gather data to determine the current levels of anthelmintic resistance on sheep farms in Wales. 
The work will involve a comprehensive Faecal Egg Count Reduction Test (FECRT) on 5 different wormer groups- 

  • Group 1-BZ - Benzimidazoles / 'White Wormer' 
  • Group 2-LV - Levamisole / 'Yellow Wormer'
  • Group 3-ML - Ivermectin / 'Clear Wormer' 
  • Group 3-ML (long acting) - Moxidectin – (e.g. Cydectin, Zermex)
  • Group 4-AD - Monepantel / ‘Orange Drench’ - Zolvix   

Samples of eggs will also be sent for molecular speciation to determine which species (if any) are surviving treatment.

Image 1- Worm eggs under microscope

How is the data collected?

 

Investigating anthelmintic resistance should be undertaken within every flock, due to various benefits: 

  • Saves money and labour time by avoiding the use of ineffective drenches and the need for repeat treatment. 
  • Using drenches that work will improve the health and production of your animals. 
  • Continued use of an ineffective drench carries a high risk of accelerating drench resistance development. Resistant worms do not die but carry on to breed.
  • Knowing how well different wormer groups work on your farm, helps when choosing which wormers to buy. 
  • Remember, long before clinical (visible) signs of worm infection occur, there have already been significant production loss. 

We need to move away from regular blanket treatments for worms, as this is only accelerating the speed of resistance and costing the UK livestock industry £3.15 million

Project Results

  • WARS Project- Once the final results are published in autumn 2024, these will be found here.