Unseasonally wet conditions has increased the threat of flystrike and worms to sheep flocks across parts of southern Australia.

Rising flystrike risk dampens outlook

EXPERTS are reinforcing the need for producers to protect their livestock as wet and humid conditions increase the threat of flystrike and worms to sheep flocks across the country.

The recent deluge of rain across many parts of the southern states, followed by warm temperatures, has created the perfect conditions for flystrike.

NSW’s Murray region and Coonamble has experienced increased worm threats, with Local Land Services recommending a December summer drench in many some cases.

In the Northern Tablelands region, NSW, concerns of barber’s pole worm have escalated with warnings of paddock contamination resulting in worm egg counts averaging 5000 eggs per gram (epg), with a range of 400 to 18,500 epg.

In Victoria, Livestock Logic director Andrew Whale warned of summer being a large flystrike risk season due to conditions. 

In South Australia, worm egg count monitoring last month indicated a general reduction in worm burdens across the state but individual mob counts over 2000epg were still evident in weaners and hoggets.

Most of the recent tests were done in the high rainfall areas - presumably harvest consuming labour in some areas  – and lower worm burdens due to the earlier slashing of pastures in lower rainfall areas.

Paraboss operations manager Deb Maxwell said producers should increase their flock monitoring following the wet conditions.

“Assess your ability to respond to a strike outbreak - if labour is short and a high level of strike is likely, apply a preventative treatment to the whole mob,” Ms Maxwell said.

“Also review your long term breeding progress towards a more flystrike-resistant flock.”

Flystrike in sheep has been estimated to cost the Australian sheep industry more than $300 million annually as a result of the cost of treatment and loss of wool and sheep production.

Flystrike is when a fly lays an egg on a sheep, the larvae or maggot hatches and starts to eat away at the sheep’s skin.

While many cases the flystriked area can be small, if sheep are not treated, or poorly managed once struck, they can be eaten alive by the maggots.

She said breed for plainer sheep as a long term goal, and treat current flystrike threats by shearing and crutching and apply preventative chemical.

“Merinos, the longer off-shears they are, have more risk for body strike,” she said.

“(Whereas) breech strike, the more wrinkly, more urine stain and longer breech wool, has more risk.”

She said with periods of intense or prolonged wet weather can increase strike risks.

Moist skin increases bacteria that causes fleece rot - the main predisposing factor for fly strike.

“There will be a point where it becomes more economic to apply a preventive treatment to the whole mob rather than treat affected individuals,” Ms Maxwell said.

“Checking and individual treatment is very labour intensive.”​