Amber warning for Welsh outbreak of Nematodirus

Wales enjoyed favourable weather conditions over the Easter holiday, but the sudden change in temperature could be problematic for lamb producers.

An amber warning has been issued to the sheep industry, alerting farmers to an increased risk of Nematodirus.

This contagious infection is a disease that affects young lambs and is caused by a worm called Nematodirus battus. A cold spell and frosty nights followed by warmer weather will inevitably increase soil temperatures, triggering a mass hatch of over-wintered parasites.

“An amber warning means that sheep farmers need to be ready to take action against the infection,” said Lynfa Davies, Technical Development Executive at Hybu Cig Cymru – Meat Promotion Wales (HCC). “It is likely that Wales will move into the red zone in the next 7-14 days and this is when the parasite reaches peak of hatching.

“The disease strikes extremely quickly and can cause a high number of mortalities whilst stunting the growth of survivors. Farmers are encouraged to be prepared and treat lambs that are at risk of infection.”

The warnings are issued by SCOPS (Sustainable Control of Parasites in Sheep), an industry-led group that was formed to develop, facilitate and oversee sustainable strategies for parasite control in sheep.

According to SCOPS, Nematodirus battushas a different life-cycle to other parasitic sheep worms and the infection can pass from one lamb crop to the next.

Lambs are more susceptible to the disease if they are exposed to pasture that was grazed by lambs last spring, are 6-12 weeks old, have been affected by stress such as fostering, and are at risk of contracting another parasitic disease called coccidiosis.The location and altitude of afarm will also affect the time of hatching.

A white (1-BZ) drench is considered an effective means of lowering the risk of an outbreak.

More information and advice can be found on the SCOPS website at

SCOPS is sponsored and represented by a wide range of industry organisations including HCC.