New online parasite forecast helps sheep farmers act fast
© Tim Scrivener A new online risk forecast for nematodirus could help sheep farmers keep abreast of the parasite and take action before it is too late.
The online tool developed by Sustainable Control of Parasites in Sheep and researchers at the University of Bristol’s School of Veterinary Sciences (SVS) predicts when nematodirus eggs will hatch and when outbreaks are likely to occur.
The forecast maps will be updated daily to track changes in risk throughout the spring and early summer and include treatment and management advice.
See also: Learn more about fluke and worm control in sheep with our Academy
What is nematodirus
Nematodirosis, caused by the gutworm Nematodirus battus, is a deadly disease affecting young lambs.
Eggs deposited on pasture by lambs the previous year hatch together in spring, triggered by a period of chilling over winter followed by warmer weather.
Young lambs take in large numbers of larvae as they graze, which damage their gut leading to black diarrhoea (black scour) and death.
Predicting when outbreaks might happen is becoming increasingly difficult due to variation in spring temperatures from year to year.
Farmers can no longer rely on a standard timetable of treatments to avoid disease.
As the damage is done by the larvae, faecal egg counts are of little use in detecting and controlling Nematodirus in young lambs.
How the forecast works
The forecast takes advantage of the temperature-driven synchronised hatching of the nematodirus larvae and uses data from 140 weather stations provided by the Met Office and Forecast.io.
The interactive nematodirus forecast Google map allows farmers and advisers to select the nearest or most representative weather station and provides advice on how to relate the predicted risk to their particular farm and treatment options.
Hannah Rose, senior research associate in the SVS, says farmers benefitted from the forecast service last year.
“They reported significant improvements in lamb health including fewer lamb deaths, less scouring [diarrhoea] better weight gain and better body lamb condition,” she says.
Five nematodirus risk factors
- Are your lambs grazing pasture that carried lambs last spring?
- Are they old enough to be eating significant amounts of grass? This is generally at six to 12 weeks of age but may be younger if ewes are not milking well.
- Do you have groups where there is also likely to be a challenge from coccidiosis? For example, mixed aged lambs are a higher risk
- Has there been a sudden, cold snap recently followed by a period of warm weather?
- Have you got lambs that are under other stresses for example triplets, fostered, on young or older ewes.