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Earlier Hatch for Nematodirus

Earlier Hatch for Nematodirus

Earlier Hatch for Nematodirus in 2014 – Farmers Beware!

The weather patterns recently recorded have led to an earlier than expected Nematodirus season.   Sustainable Control Of Parasites in Sheep (SCOPS) have just published a red warning for the South West which has come some 2-3 weeks earlier than in 2013.  Using soil temperature data produced by Bristol University, their risk analysis map shows the South West of England is expected to see a peak hatching in the next 7-10 days, with the red zone spreading North over the next month.

Check your regions disease status by logging onto the SCOPS website:

Due to the unique lifecycle of Nematodirus, in comparison to other round worms, disease caused by this parasite can be particularly nasty with the potential for high mortality.  Nematodirus has the ability to over winter well on pasture, with the infective larvae developing inside the protective eggs. Once the conditions are right, a mass emergence of larvae occurs over a very short time frame.  

The infective immature larvae go onto cause intestinal damage within lambs before their eggs appear in faeces.  As such, faecal egg counts are usually of very limited use with Nematodirus and waiting for Nematodirus to be confirmed before treating would be ill advised.

The main risk factors for Nematodirus are:

1. Lambs grazing pasture that was grazed by last year's crop

2. A sudden cold snap that is swiftly followed by warmer weather

3. Lambs that are old enough to be grazing significant amounts of grass coinciding with the right weather conditions to trigger mass emergence

4. Lambs also faced with other parasitic challenges such as coccidiosis

If you are in a known risk area for Nematodirus or you have had problems in the past early treatment would be very advisable.  Both white and yellow drenches can be used to treat Nematodirus, with SCOPS recommending the white (1-BZ) drenches.  As with all drenching it is very important to follow the SCOPS guidelines on correct drenching technique to ensure each lamb is given the correct dose for its weight. 

We stock many sheep wormers



Source Details

Written by Mark Riggs,  Head Vet BVetMed MRCVS (Head Vet until December 2014)

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