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Parasite Matters Summer 2022

The weather for April and May showed a North/South and East/West split depending on whether you are looking at temperature or rainfall. April was warmer in the West of the country and cooler in the East; but drier in the South, with only the North of Scotland having more rainfall than average. In May, temperatures reverse – warmer in the East and cooler in the West with a rainfall about average apart from the West coast of Scotland, which was wetter than normal.

Overall, it has been a sunny and warm Spring for most of the country. So, what does this mean for parasite activity?

Weather Charts from Spring 2022 - courtesy of the Met office


  • Nematodirus The challenge started early in the South this year but has been slower to develop in the North of the country. By June we are expecting the bulk of the challenge in the South of the country to have passed and even in the North and Scotland, peak challenge will have passed. There might still be some isolated pockets where nematodirus is still a risk so check the the SCOPS nematodirus forecast and check samples for coccidiosis if you have scouring lambs and a low risk forecast.
  • Other GI worms Although anthelmintic resistance is one of the biggest challenges faced by all sheep flocks, it is largely invisible unless we undertake some level of testing to see how effective our treatments have been. Resistant worms left behind after treatments can reduce lamb growth rates by up to 50% without any visible signs. Also, with the variability in weather, dry summers often mean there is little or no worm challenge during the traditional ‘’summer worm season’’. Applying a ‘’test don’t guess" approach, by doing regular faecal egg counts (FEC) throughout the grazing season will allow you to both avoid unnecessary wormer treatments and treat before any damage has been done. Visit to make use of our useful tools such as the Elanco Sheep Wormer Checker and video on how to FEC .

  • Liver Fluke For effective and sustainable liver fluke control, managing this parasite is a year round project. See for the 4 point control plan. As for worms, the fluke season changes with the weather, so adopting a test don’t guess approach is the best way to target treatments with the right active for the right animals at the right time. Most areas will be ‘’low risk’’ of having infectious stages of fluke on the pasture until later in the season. Keep an eye on the next bulletin for an update.
  • Blowfly Although the NADIS forecast is increasing, the reports of strike are appearing ahead of the high risk forecast this year. See the blowfly tracker for reports in your area. As the weather warms through the summer, the blowfly risk is likely to increase exponentially, with the highest risk being in August and September, in recent years. Application of preventative products before the fly risk peaks is the best way to reduce the risk of strike. See for more information and tips for correct application of the blowfly products range.

  • A2K Hybrid Event Join us for the Elanco Access to Knowledge event, on the 5th July 2022, hosted by presenter, author and farmer - Adam Henson. The theme of the event is ‘’Routes Ahead’’ – with a presentation from SVS president, Rebecca Mearns, on the Animal Health and Welfare Pathway and how to maximise this opportunity on Farm.

Parasite Matters Archive

Parasite Matters Spring 2022 (published April 2022)
Parasite Matters Autumn 2021 (published September 2021)
Parasite Matters Summer 2021 (published June 2021)
Parasite Matters Spring 2021 (published March 2021)

CLiK™ EXTRA 65 mg/ml Pour-On Suspension for sheep contains dicyclanil and is indicated for the prevention of blowfly strike on sheep caused by Lucilia sericata or Wohlfahrtia magnifica. CLiK™ Pour-On for sheep contains 5% (w/v) dicyclanil and is indicated for the prevention of blowfly strike due to Lucilia sericata or Wohlfahrtia magnifica on sheep CLiKZiN™ Pour-On Suspension for Sheep contains the active ingredient dicyclanil and is indicated for the prevention of blowfly strike on sheep due to Lucilia sericata. Dectomax 5 mg/ml Pour-On Solution for Cattle contains doramectin and is indicated for treatment of gastrointestinal roundworms, lungworms, eyeworms, warbles, sucking and biting lice, mange mites and hornfly in cattle. POM-VPS Flypor™ 4% w/v pour-on solution contains 4% w/v permethrin (cis:trans 80:20). Legal category: POM-VPS. Rycoben™ SC 2.5% w/v Oral Suspension for Sheep contains cobalt sulphate, ricobendazole and sodium selenate, and is indicated for the control of broad spectrum roundworms, tapeworms, lungworms and fluke in sheep. POM-VPS. Advice should be sought from the medicine prescriber prior to use. Use medicines responsibly ( Weather maps courtesy of the Met Office. For further information call Elanco Animal Health on +44 (0)1256 353131, or write to Elanco UK AH Limited, Form 2, Bartley Way, Bartley Wood Business Park, Hook, RG27 9XA. CLiK™ EXTRA, CLiK™ Pour-On, CLiKZiN™, Dectomax™ Pour-On, Flypor, Clikzin™, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. ©2022 Elanco or its affiliates. PM-UK-22-0317