A forecast has been issued that details where and when the peak nematodirus egg hatching is expected across the country.
In 2024, this forecast shows that peak nematodirus egg hatching is expected to have occurred at the end of March in much of Munster and south Leinster.
Much of the midlands and northern half of the country will see peak egg hatching in the early days of April.
This slightly earlier hatching is due to the overall milder conditions during March.
Nematodirus worms may cause severe diarrhoea in young lambs in spring, caused by the tendency of the worm eggs on pasture to hatch over a short period of time, leading to a surge in the numbers of infective larvae on the pasture, which the lambs ingest.
Each spring, the Department of Agriculture, Food and the Marine (DAFM), in collaboration with Met Éireann, University College Dublin (UCD) and Teagasc advises farmers of the predicted risk of disease, chiefly in lambs, caused by the roundworm nematodirus battus.
The analysis of March soil temperatures allows the period of disease risk to be accurately forecast.
This can be used to gauge the optimal time to administer treatment to prevent disease.
DAFM advice on nematodirus
The DAFM stated that: “Twin lambs, or single lambs born to ewes of poor milking ability may be at a greater risk of developing the disease as they begin consuming greater amounts of grass earlier in life.
The department recommended at-risk lambs (i.e. typically six to 12 weeks of age and grazing on contaminated pasture) should be treated approximately two weeks after the peak of nematodirus egg hatching.
As both nematodirosis and coccidiosis can occur at the same time, the DAFM advised treatment “may need to be directed against both pathogens”.
The DAFM has recommended that any lambs that die unexpectedly are referred by your private veterinary practitioner to a regional veterinary laboratory for post-mortem examination “as nematodirus can cause death before clinical signs become apparent”.