Please be aware that this website relies on the use of cookies to function correctly and involves some cookies being downloaded onto your device. This helps us to improve the content of the website so that it is more useful and relevant to you.
Allow cookiesPrivacy and Cookies Policy
banner image

Winter 2019 (Updated December 2019)

Welcome to the Winter edition of Parasite Matters from Elanco Animal Health. As the end of the calendar year approaches, we can look back on a year that was generally warm and damp, but also gave us some localised extreme weather conditions.

From the parasite point of view, this translated into a very high blowfly challenge across the country, with localised areas where 'thunder bomb' rainfall conditions shortened the expected duration of cover from blowfly prevention treatments.


Courtesy of the Met Office


  • The autumn conditions were ideal for worms to thrive, and in areas where there has not already been a hard frost, there will still be pastures with a very high worm burden. Pastures that carried lambs in the autumn will be the highest risk for grazing lambs next spring and summer.
  • Focusing on ewe body condition (ie managing feeding to maintain ewes at BCS 2.5-3.5 regardless of what the weather throws at us) through mid pregnancy and in the run up to lambing will manage the periparturient rise in egg output to a large extent, and pay dividends in terms of colostrum quality and milk supply. This gives the lambs the best possible start. Combine this with avoiding grazing this autumns high risk pastures with lambs until the second half of the grazing season, and you can minimise worm challenge to keep lambs growing at their best through the summer.

Liver Fluke

  • We are in the middle of the fluke season, and although the recent cold weather will have curtailed snail activity, the metacercaria (infectious cysts) already on the pasture tolerate freezing very well. These will provide a challenge for the rest of the winter in all the areas where the mud snails were active in the summer and autumn. As the summer/autumn weather was ideal for the snails, there could already be very high numbers of metacercaria in these areas, just waiting to be eaten by livestock. As a result of this the fluke risk forecast is still high for a large part of the country (see the NADIS parasite forecast for details.
  • Go to or scan the QR code below to see where mud snail habitats might be, and enter our competition for your chance to win a Bose speaker by finding Fred the Fluke.

Finally, as this is our last bulletin for 2019, all at Elanco would like to take this opportunity to thank you for your support this year, and wish you a happy, healthy and prosperous 2020.

Parasite Matters Archive

Parasite Matters Spring (published March 2019)
Parasite Matters Summer (published May 2019)
Parasite Matters Autumn (published September 2019)


“Livestock producers are aware that coccidiosis can cause severe gut damage and productivity losses” says sheep farmer Mike. Watch Mike talk about his experiences here (2mins video)

For further information call Elanco Animal Health on +44 (0)1256 353131, write to Elanco Animal Health, Lilly House, Priestley Road, Basingstoke, Hampshire, RG24 9NL. Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. Use medicines responsibly ( Map courtesy of the Met Office.