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 Primary Industries and Regional Development provides recommendations for the most effective approaches to the control of the major parasites of livestock

Articles

  • Taenia 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 trimming of sheep

  • The most common lice affecting sheep are body lice (Bovicola ovis).

  • Drench resistance in cattle worms has been found in tests in several countries in recent years, prompting an investigation into the situation in Western Australia.

  • Worm control and drench resistance management in livestock is most efficient and sustainable when there is an indication of the size of worm burdens and the effectiveness of drenches.

  • Nasal bots are the maggots or larvae of the sheep nasal bot fly, Oestrus ovis.

  • The liver fluke, Fasciola hepatica, is a serious parasite of ruminants, which can cause severe damage to the liver and consequently disease, production loss and even death.

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

  • 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

  • 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.

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