Livestock parasites

Parasites are a major cause of disease and production loss in livestock, frequently causing significant economic loss and impacting on animal welfare. In addition to the impact on animal health and production, control measures are costly and often time-consuming. A major concern is the development of resistance by worms, lice and blowflies to many of the chemicals used to control them. 

Planned preventative programs are necessary to minimise the risks of parasitic disease outbreaks and sub-clinical (invisible) losses of animal production, and to ensure the most efficient use of control chemicals.  Integrated parasite management programs aim to provide optimal parasite control for the minimal use of chemicals by integrating pre-emptive treatments, parasite monitoring schedules and non-chemical strategies such as nutrition, genetics and pasture management. 

The Department of Agriculture and Food, Western Australia provides recommendations for the most effective approaches to the control of the major parasites of livestock


  • 21 November 2016

    It is important that parasites in beef are adequately controlled in order to maintain healthy productive cattle.  The immune responses of adult cattle to parasites are such that fewer drenches are

  • 4 November 2016

    Large burdens of parasitic worms lead to reduced productivity in cattle. Typical signs are diarrhoea and poor body condition.

  • 11 September 2017

    Treatment of ewes and lambs is more complex than treatment of a mob of single animals because they exist as a unit of two or three animals in close contact rather than individuals within in a mob.

  • 11 September 2017

    The sheep industry relies heavily on drench chemicals to control sheep worms but in Western Australia (WA) worms have become increasingly resistant to drenches.

  • 18 October 2017

    The impact of parasites on sheep can range from being virtually undetectable, through to obvious clinical signs or even death.

  • 19 April 2017

    The bush tick (Haemaphysalis longicornis) is a parasite of cattle, sheep and other warm blooded animals.

  • 13 October 2017

    Flystrike is a significant health and welfare risk to Australian sheep and costs $280 million annually.

  • 21 November 2016

    Cattle lice cause irritation and rubbing that results in hair loss and poor coat quality. Cattle won’t always require treatment for a skin problem resulting from a lice infestation.

  • 28 September 2017

    Gastro-intestinal worm infections in sheep are a major cause of lost productivity to the Western Australian (WA) sheep industry and control has become more complex due to widespread drench resistan

  • 2 August 2017

    Taenia ovis (T.ovis) (otherwise known as Cysticercus ovis, ‘ovis’ or ‘sheep measles’) is a tapeworm parasite which can cause significant economic loss due to the rejection or trim