A5 Q2 Torch Summer Magazine 2024 - Flipbook - Page 20
BEWARE THE BLOW FLY!
By Sasha Wicks BVMedsci BVM BVS
About the blow昀氀y
With the warmer weather making somewhat of an arrival, most stock owners are aware of
the risk to livestock this can bring. The blow昀氀y is a common insect which many would see
as merely a pest. However, the health and produc琀椀on implica琀椀ons on a 昀氀ock can be catastrophic. When condi琀椀ons are right, signi昀椀cant numbers of blow昀氀y eggs can hatch with strike
occurring in as li琀琀le as 24-36 hours once the eggs are laid.
The life cycle
Understanding the life cycle of the blow昀氀y aids with understanding the importance of preventa琀椀ve measures. Once soil temperatures are above 9 degrees, larvae on the pasture that
have remained throughout the winter begin to hatch and mature into adults. The female 昀氀ies
are a琀琀racted to wounds or faeces on the sheep, especially around the withers, 昀氀ank and tail.
These 昀氀ies will lay hundreds of eggs on the animal which will then hatch, eventually feeding on
the skin leading to further wounds.
Around 3 days later, the mature larvae will drop o昀昀 the sheep and mature into a new wave of
adults. As each cycle occurs, the popula琀椀on of 昀氀ies increases.
Blow昀氀y strike
Blow昀氀y strike is a major concern with regards to welfare of stock and can be a costly impact
to margins. The symptoms of blow昀氀y strike can range from restlessness, with some agita琀椀on,
to gnawing and scratching at the impacted area. Ul琀椀mately, the condi琀椀on can lead to death. If
one animal within the 昀氀ock is a昀昀ected, the likelihood is that there are others at risk or within
the early stages of disease. If blow昀氀y strike occurs, losses can be signi昀椀cant. Control of blow昀氀y
strike is largely aimed at preven琀椀on in order to reduce the need for treatment.
Control of blow昀氀y strike
Preven琀椀on of blow昀氀y strike is the mainstay of control within a 昀氀ock and applica琀椀on and 琀椀ming
is key. There is a variety of pour on treatments on the market to aid with 昀氀y and ectoparasite
control, make sure you get advice as to the best product for your needs as well as making sure
you have the right gun for accurate applica琀椀on. The majority of these will contain either:
•
Cypermethrin/ Deltamethrin (used for treatment and preven琀椀on) depending on the
product can last up to 8 - 10 weeks
•
Dicyclanil (preven琀椀on only) and depending on product can last up to 19 weeks.
This will help give peace of mind to stock owners who may become concerned as the warmer
weather draws in. The aim of control is to reduce the popula琀椀on of 昀氀ies in the environment to
reduce the suscep琀椀bility to the 昀氀ock. For advice or if you have any concerns, please phone the
prac琀椀ce to speak to a vet.
