With risk levels rising sharply in the last seven to 10 days, the SCOPS Nematodirus Forecast is warning that many areas of the UK now at ‘high’ or ‘very high’ risk levels for lambs that are six weeks old.

In the cooler regions of the UK, temperatures have yet to reach the threshold so farmers in these areas need to watch the forecast carefully.

Lesley Stubbings of SCOPS (Sustainable Control of Parasites in Sheep) explained: “This year has been very different.

The warm spell in February put early-born lambs at risk and many farmers had to treat earlier than normal. And then, as predicted, we also saw risk levels rise again after the cold start to April.

"Following the free online forecast has provided a valuable guide for sheep farmers and we have had some positive feedback from users.”

Kerry Sykes-Marsden, a shepherd with for 900 ewes in Lincolnshire, agreed.

She said: “The SCOPS forecast has taken the guesswork out of controlling nematodirus.

Based on the advice on the website, we’ve treated lambs earlier this year and this has avoided the ‘wait and see’ approach when we haven’t acted in the past to see clinical signs.

"Some years we have just gone in and wormed at six weeks of age, which could be too early or, even worse, too late.”

The SCOPS Nematodirus Forecast map is updated daily using data from 140 weather stations (provided by the Met Office and DarkSky), tracking changes in risk throughout the spring and early summer.

The interactive map allows farmers and advisers to select the nearest or most representative weather station and then provides advice on how to relate the predicted risk to their particular farm, treatment options and possible management actions.

A new feature this year is a table that shows when each location on the map has changed colour.

Stubbings added: “The historic data is a really useful tool that I recommend having a look at.

"In some areas, the colours have gone straight to black (without turning red) which emphasises the rapid fluctuations in temperatures we have had.”

Sheep farmers should consult their vet or adviser with regard to local risks and treat lambs if they are deemed to be at risk.