The warm conditions over the past two weeks have seen cases of Blowfly strike noted in lowland sheep flocks across Ireland.
Blowflies are an external parasite that commonly appear over the summer months, however, depending on the weather, cases as early as April and as late as November can also occur.
With the rise in temperatures, fly populations have increased and with this, the risk of Blowfly strike has also increased.
Risk from Blowfly strike
Sheep that have a soiled fleece are at the highest risk of flystrike. Where shearing will not take place in the coming weeks and farmers are concerned about flystrike, dagging/crutching dirty sheep will help to reduce the risk of blowfly strike in the short-term.
The most common area for a sheep’s fleece to be soiled is around the tail or rump region. However, they can also become infected on the shoulder, along the back or where a cut has occurred on the skin.
Blowfly strike occurs when flies are attracted to a foul-smelling, soiled fleece. The flies land and deposit eggs onto the affected sheep.
These eggs hatch into larvae or maggots and begin to feed on the sheep’s skin – causing severe discomfort.
Symptoms
Obvious symptoms in sheep that have been affected with flystrike include: Foot-stamping; vigorous shaking; scratching; restlessness; wool loss or discoloured area of wool; and loss of body condition.
At this time of year, shearing ewes is the best option to protect them from flystrike and a treatment can be administered in a few-weeks time.
While stock rams and ewes are at risk of flystrike, farmers should not forget about the risk it poses to their lambs also.
Flystrike will decimate lamb performance and will result in death if left untreated. As always, prevention is better than cure and farmers should monitor their sheep closely for cases of flystrike.
Plunge-dipping or pour-on products are the preferred methods to prevent flystrike in lambs. Farmers should be conscious of the withdrawal periods when using these products to treat their lambs.
Some long acting pour-on products have a meat withdrawal period of up to six weeks however there are pour-on products with withdrawal periods as low as seven days.
The key message is to monitor stock closely, shear ewes when possible and seek advice from your veterinary practitioner on the best treatment to prevent/control flystrike cases in the flock.