Parasite Watch, Sheep farming

The Unpredictable 2016 Sheep Parasite Threat

From most areas of the UK, feedback suggests that last year was one with low to moderate roundworm burdens, Looking ahead to the 2016 grazing season, price pressure on finished lamb and beef, or indeed milk, mean intense scrutiny on costs of production. It is important however to understand that cutting costs may actually have an impact on production, exacerbated if the parasite challenge is high.

Sheep Grazing in Open Field

For example, fewer worm treatments because of known low parasite burdens on pasture can offer genuine savings. But it would be false economy in the face of moderate- to high-infection pressure due to the impact of roundworms on growth rates. This applies equally to sheep and cattle. Clearly a balance must be struck between avoiding unnecessary use and cost of wormers on the one hand, whilst pursuing a growth-rate dividend when worming is justified on the other.

With the latter in mind, gastrointestinal worms can reduce summer growth rates long before signs start to show as loose faeces and dirty rumps, according to former SAC adviser Dr Basil Lowman. In growing cattle for example, he has said unseen worm infections could easily reduce growth by 0.1kg a day.

On good pasture, 1kg/day live-weight gain should be possible, according to a factsheet published by Eblex (now AHDB Beef & Sheep). But a mere 10% shortfall could mean 20-30 days of additional feeding next winter to reach a target weight, or selling a 20kg lighter beast in the autumn. Either way, the likely extra cost is in the region of at least £40/head. The same principles can apply proportionally to lamb growth rates post-weaning.

Due to this uncertainty, Zoetis is planning to establish a network of Parasite Watch farms across the UK to provide 'live' information on the challenge from four key parasite types:

Gastro-intestinal worms – regular Faecal Egg Counts (FECs) and growth rate monitoring to check for the onset of parastitic gastro-enteritis.

Nematodirus – regular FECs, weather data and other sources to give an indication of disease risk on sentinel farms.

Liver Fluke – using risk and weather data, coupled with regular sampling on Parasite Watch farms, to provide early notice of predictable threats.

Flies – data from Parasite Watch Farms to prompt early warnings, possibly before it is noticeable around livestock, that fly populations, are multiplying quickly.

Parasite Watch

Overall, the aim of Parasite Watch will be widespread evidence-based decisions to treat or indeed not treat. It will inform vets, SQPs and farmers if they are able to reduce treatments or whether the impact on production, given the parasite challenge, is likely to be too high a risk. Intelligence derived from Parasite Watch farms combined with other reliable information sources will be communicated to farmers via animal medicine suppliers and veterinary practices, the press and social media. If you have any questions about Parasite Watch or want to know how to get involved, comment below and we’ll do our best to reply to you as soon as possible.


For further information please contact your veterinary surgeon or Zoetis UK Ltd, Walton Oaks, Tadworth, Surrey, KT20 7NS support: 0845 300 8034. Use medicines responsibly (