Sheep farmers encouraged to monitor nematodirus risk
© Tim Scrivener Sheep farmers are encouraged to monitor their flock’s risk of nematodirus following recent warm weather, which can influence when this parasite’s larvae hatch.
Nematodirosis affects lambs and can cause a high number of mortalities and stunt the growth of many others.
See also: How to control gastrointestinal parasites in sheep and cattle
To help identify the risk and ensure timely and effective interventions, the Sustainable Control of Parasites in Sheep (Scops) group is once again offering its nematodirus forecast for free to farmers, vets and advisers.
The Scops forecast predicts the hatching of Nematodirus battus based on local weather conditions and the interactive map, updated daily with data from 140 weather stations (Met Office and DarkSky), providing a guide to the risk level.
Causes
Caused by the Nematodirus battus worm, nematodirus can strike very quickly, with little or no warning in certain climatic conditions.
Nematodirus eggs already on the pasture from last year’s lambs typically require a period of cold weather followed by warmer temperatures of 10C or more to hatch.
If these conditions occur in quick succession, it can trigger a mass hatch, which if it coincides with lambs beginning to consume significant amounts of grass (at around six weeks of age) can have a devastating impact.
Independent sheep consultant Nerys Wright said: “This year in particular we have seen some significant fluctuations in temperatures, making the time of hatching difficult to predict without the forecast.”
Prevention
By using the forecast tool in combination with grazing history, aspect and altitude for each group of lambs, farmers can better assess the risk of infection and take timely preventive measures.
Faecal egg counts, Dr Wright added, are not a reliable indicator of current risk and the damage is caused by immature larvae that do not produce eggs and will not be found in samples.
Dr Wright recommended that producers speak to their vet or animal health adviser and visit the Scops website for further information.