Sheep farmers are being warned to act now and take preventative measures, as blowfly strike warnings are being sent to farmers in Northern Ireland.
The recent week of hot weather will have resulted in an expected increasing strike risk, so preventative measures should now be in place.
According to the National Animal Disease Information Service (NADIS), blowfly strike is a serious disease thought to affect over 80% of farms in the United Kingdom (UK).
‘Blow’ refers to the laying of eggs by flies and ‘strike’ is the damaged caused by the larvae (maggots).
In addition to treatment, early shearing substantially reduces the strike risk for ewes at the start of the strike season.
Getting good early control of gastrointestinal worms will help to reduce the strike risk in lambs going forward through the season.
The map below indicates the areas of the UK that have a higher or lower risk of blowfly occurring. The green, amber, and red areas show the respective threats:
- Green: Low risk (flystrike unlikely);
- Amber: Medium risk (act now);
- Red: High risk (flystrike likely).
Even in areas where no or low general risk is currently expected, at this time of year, risk is never zero because some maggots may have overwintered in unusually warm parts of the environment, allowing them to emerge early.
Blowfly prevention
Elanco ruminant technical consultant, Matthew Colston, has urged farmers in the north to be vigilant and apply a preventative treatment to protect their flock before strike occurs.
However, the true economic impact of blowfly strike is often underestimated with costs of £209/lamb, and £184/breeding ewe, being quoted, according to Elanco.
Colston said early preventative treatment has been shown to be the most cost-effective strategy to combat the flock health and economic risks due to blowfly strike.
“We recommend protecting your flock by applying an insect growth regulator (IGR) product,” Colston added.
He shared his top tips to get the most out of preventive fly control treatments:
- Apply early in the season – every season is different, so check risk forecasts for a guide as when to treat;
- Use an applicator gun with a fan spray nozzle and carefully calibrate it before use;
- Apply to a clean fleece – clip or dag any dirty animals before application;
- Apply the product in a band approximately 10cm wide (holding the gun approximately 45cm from the sheep). Apply the total required dose one quarter at a time, using the four-stroke method;
- Take care to overlap each stroke and ensure it is down the centre of the back to allow the formulation to evenly spread over the fleece to achieve full protection.
Blowfly strike can happen very quickly, with 94% of farmers reported to have been caught out by it.
Farmers can sign up to Elanco’s blowfly watch alerts, farmers will get the heads up on when to apply a preventive treatment before cases occur.
Farmers can also report cases of strike on the Elanco blowfly tracker to help alert other farmers to local cases.