Nematodirus

We have recently seen a run of Nematodirus cases in lambs in our PM room. The whole of Scotland and Northern England is currently showing as high or very high risk on the Nematodirus forecast, and we usually see our peak of cases in late May and early June in this area of South West Scotland.

Some cases are complicated by mixed worm species infections and coccidiosis as well.

Long cold springs tend to increase the nematodirus risk in six to twelve week old lambs. The hatch of overwintered eggs occurs later by which time the main crop of lambs are eating enough grass to ingest significant numbers of infectious larvae.

Fields where there was an issue in 2023 will be high risk this year and should not grazed by the most susceptible lambs. Remember that diarrhoea and death can occur before infection is patent therefore postmortem examination can be required to confirm the diagnosis.

Some flocks or groups of lambs may have been treated too early so consideration of retreatment may also be indicated.

Close liaison with the whole farm team over flock health planning and targeting of any anthelmintics used relative to risk is particularly important just now.

Posted by SRUC Veterinary Services on 13/06/2024