Nematodirus parasite forecasting tool relaunched

The wet winter is set to result in an extremely variable challenge to young lambs from nematodirus across the country
The wet winter is set to result in an extremely variable challenge to young lambs from nematodirus across the country

A forecasting tool has gone live to help farmers check the risk of nematodirus to lambs this spring following the mild, wet winter.,

The alert map will go live from 2 March, showing when hatching of nematodirus eggs is predicted based on local weather conditions.

The exact date of hatching can be influenced by variation in microclimate, and early cases are also possible from overwintered larvae, according to map creators the Sustainable Control of Parasites in Sheep (SCOPS).

A link on the forecast also gives access to an archive section, so vets and farmers can consult previous forecasts and see when the risk levels changed in their area.

Hatching has been seen in January in some areas and although the colder conditions in early February could slow things down, experts believe a protracted hatch is likely.

This could catch sheep farmers out if they are not watching the forecast and assessing the risk to their lambs, sheep experts say.

“When deciding whether or not to act, sheep farmers must also take into account variation from field to field and farm to farm," says Dr Hannah Vineer, of Liverpool University, who was instrumental in developing the forecast.

“It is important to assess the risk to each group of lambs based on the history of the field and it’s aspect and altitude."

She adds: "South facing fields tend to have an earlier hatch and every 100m increase in altitude will delay hatching by about 7 days.

"For example if the nearest station is at 200m above sea level and the farm is at 100m above sea level, hatching could be around 7 days earlier than our forecast”.

“Moving lambs to lower risk grazing that was not grazed by lambs last spring will help to avoid a high challenge," explains Dr Vineer.

"However, nematodirus eggs were commonly seen in faecal samples from sheep of all ages throughout 2019 which means that even land grazed by older sheep could be contaminated.

"Although faecal egg counts cannot be used to decide when to treat young lambs for nematodirus, as the damage is done by larvae that don’t produce eggs, regularly monitoring and recording faecal egg counts can help track which fields provide the safest grazing for lambs come spring.”

Experts at SCOPS also say that it is important to monitor for signs of diarrhoea and ill thrift.

They urge farmers not to exclude nematodirus as a cause of disease in lambs even if the regional hatching risk is not high.

Sheep farmers having had cases of nematodirus confirmed on their farm are requested to help inform the forecasting tool themselves by logging their cases on the website using the first half of their postcode.