The Sustainable Control of Parasites in Sheep (SCOPS) Group is once again offering its invaluable Nematodirus Forecast to help farmers, vets and advisers identify when lambs might be at risk of exposure to nematodirus, ensuring timely and effective interventions.

Speaking on behalf of SCOPS, independent sheep consultant Nerys Wright says: “The SCOPS Nematodirus Forecast is an essential tool due to the role of temperature on the larvae of this worm species. This year in particular we have seen some significant fluctuations in temperatures, making the time of hatching difficult to predict without the forecast. Currently, the map indicates there are some very high risk areas, as marked by black dots, which is earlier than in previous years. Lambs born from mid-February onwards that are old enough to be grazing are currently at the highest risk. Most March-born lambs are currently too young to be affected.”

Analysis of historic forecast data from 2019 to 2024 highlights the variation in the timing of the nematodirus hatch, corresponding to temperature fluctuations. The two graphs below illustrate the difference in the timing of the very high-risk period for two weather stations, one in England and one in Scotland.

Dr Wright adds: “The range between the earliest and latest onset of very high-risk varies by six to seven weeks over a five-year period, highlighting that treatment at set times is unlikely to be effective. Neither can we risk a wait-and-see approach because when an outbreak occurs, as Nematodirus can rapidly cause severe harm or even death to a large number of lambs. The forecast helps to pinpoint the timing of any treatment given.”