NADIS & Elanco Blowfly Alert reports ‘severe risk’

Real-time updates on blowfly risk – produced via an ongoing collaboration between Elanco and NADIS (National Animal Disease Information Service) – now show the risk level has increased to ‘severe’ across all but one region of the country.

Richard Wall, Professor of Zoology (Ectoparasite Specialist) and compiler of the Blowfly Risk Alerts, said: “Warm, humid weather is perfect for blowflies and increases the survival of any maggots on the sheep. This time of year is the peak of the strike season, the risk of strike is severe across most of the country.

“Fly populations are at their maximum, any lambs still on the farm are at high risk, and the risk for ewes is increasing as their fleece regrows. High levels of vigilance are therefore required even if animals have been treated against strike”.

Regional Alert breakdown 

Region Score
NW Scotland High
E Scotland Severe
NE England Severe
E Anglia Severe
The Midlands Severe
S England Severe
SW Scotland Severe
NW England Severe
N Wales Severe
SW England Severe
S Wales Severe
N Ireland Severe

NADIS Map key|
Low risk: No significant risk
Medium risk: One in 2,500 animals might be struck
High risk: One in 500 animals might be struck
Severe risk: One in 100 animals might be struck

Kate Heller, Elanco’s ruminant technical consultant, said that farmers are being urged to ‘strike first’ with preventative treatments rather than risk devastation to their own flock.

She said: “A lot of farmers think “it’s not in my control” because of bad weather or other circumstances. They’re unnecessarily putting limits on themselves. Blowfly strike is not an inevitable part of farming and can be mostly avoided with the right management strategy.”

“When farmers are looking at treatment options, they need to look for the longest protection with an IGR that binds to the fleece – It is now possible to get 19 weeks blowfly strike prevention. There are no guarantees when it comes to blowfly strike – with significant levels identified into November, an essential part of any strategy, has to ensure an early treatment that extends right through the long season.”

National Farm Research blowfly study
Results of an Elanco blowfly study conducted in partnership with the National Farm Research Unit found that 99% of farmers having suffered financial losses as a result of blowfly strike. While 82% agree that the blowfly season is getting longer, with cases of strike being reported as early as February and as late as November.2

The cost
The consequences of blowfly strike can be devastating, leading to production losses and welfare problems. By comparison, preventing blowfly strike using a long-lasting product can offer not only peace of mind but can also be economical in terms of time, money and effort.

Blowfly strike: financial losses Compared to blowfly treatment
£200 – breeding a replacement ewe
£80 – loss per lamb death
£10 – production loss per struck lamb
£10 – labour costs handling struck animals Treatment – 50p per animal


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