Flies thrive in warm, wet conditions. So, with higher-than-average rainfall forecast for much of eastern Australia this spring, there is potentially a greater than usual flystrike risk. Now is the time to implement your annual flystrike management plan – and if you haven't got one, it is best to develop one quickly because a wave of blowflies could soon be on its way.
As the days heat up and the spring storms roll in, blowfly (Lucilia cuprina) larvae are beginning to emerge from the ground. Temperatures of more than 17˚C increase fly activity following winter hibernation. Low to moderate wind speeds and a moist fleece create optimal blowfly wave conditions. As the blowfly lifecycle is 2.5–3 weeks in warm weather, woolgrowers can expect to see blowfly populations boom three weeks after a significant spring or summer storm.
Early prevention of flystrike is key to minimising welfare and economic threats, so it's now time to start your annual flystrike management plan.
Key components of your plan should consider:
1. Time of crutching, shearing and lambing
The time of lambing is arguably one of the most significant husbandry decisions any woolgrower will make. Depending on the system, there will be different risk factors including:
a. Autumn lambers will need care over the joining period and weaned lambs will need care into their first spring. In this system, woolgrowers also need to consider the rams – if you are shearing rams pre-joining, do this at least six weeks prior to ensure semen quality is not affected by handling.
b. Spring lambers will need care over the lambing period and lambs may need care into the autumn.
It is advisable to discuss labour availability with your shearing contractor if you are considering changing your time of shearing or crutching, or increasing the frequency of shearing.
2. Breech modification and tail docking length
Many woolgrowers are now looking at what is required to reduce their reliance on mulesing and options for the provision of analgesia and local anaesthesia in the interim. Considerations for reducing the reliance on mulesing include your flystrike risk intensity and period, the susceptibility of your current flock, what breeding objectives your flock needs to achieve to suitably reduce the risk, and chemical and physical management tools that can be implemented to reduce risk during peak blowfly seasons.
