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Wet spring unleashes mozzies, flies and worms on vulnerable stock

Wet spring unleashes mozzies, flies and worms on vulnerable stock

A wet spring has unleashed a swarm of mosquitoes and an influx of worms in Western NSW putting livestock at risk of disease and health problems not usually seen in drier seasons.

Dr Charlotte Cavanagh, District Veterinary Officer with Local Land Services Western Region, warns stock are vulnerable to serious health issues such as three-day sickness, fly strike, and internal parasites in warm, wet weather.

“Many Western producers have noticed an increase in mosquito numbers following recent rain activity. Mosquitoes are a major vector (source) of bovine ephemeral fever virus, commonly referred to as Three Day Sickness,” said Dr Cavanagh.

Infected animals show flu-like symptoms of fever, drooling, watery eyes, stiffness, and lameness. Bulls and heavy cows tend to be most severely affected.

“Recovery time will be improved if cattle are treated with anti-inflammatory drugs to decrease the fever, while calcium injections will also assist in getting affected animals up on their feet more quickly,” said Dr Cavanagh.

“Most animals recover rapidly with appropriate treatment, however bulls may suffer from temporary infertility and there may be a transitory reduction in milk yield in cows.”

Three Day Sickness can be prevented through veterinary-prescribed vaccination and by reducing fly and insect numbers.

Insect repellent ear tags can be purchased from rural retailers and provide relief to stock from constant insect attack.

Warm weather coupled with constant rainfall has also created perfect conditions for flystrike, with many producers reporting above average numbers of fly struck sheep.

Producers are urged to complete flystrike prevention treatments early and Local Land Services District Vets are very happy to provide advice on flystrike management.

“If you have access to the internet, the Flyboss website ( has some fantastic information and toolkits for producers,” said Dr Cavanagh.

Problems with internal parasites have also increased in the Western Division with the rain, impacting on production and causing stock deaths in recent months.

“Worm egg counts have been highest in areas with the most rainfall. A monthly worm test is recommended during this high risk season, and a drench check is always advised after treatment. Testing kits are available through your local District Vet,” said Dr Cavanagh.

Producers can ring Local Land Services District Vets for further information and interpretation of results. Additionally the WormBoss website ( provides up to date industry research and information for Western sheep producers.

Livestock producers are encouraged to call their Local Land Services District Vets if they have any concerns about ill livestock or questions about animal health:

Dr Charlotte Cavanagh, District Veterinary Officer (Bourke office) – 0429 773 021


Dr Sophie Hemley, District Veterinary Officer (Broken Hill office) – 0417 248 135


Media contact:  Meg Strang for Local Land Services Western Region - 0429 340 600.