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

Articles

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

  • It is important that parasites in beef are adequately controlled in order to maintain healthy productive cattle.

  • 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.

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

  • 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.

  • When the prevalence of sheep lice is high as it is in Western Australia (WA) at the present time there is a greater probability that lice will be present in any flock.

  • 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.

  • 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.

  • Lost productivity due to drench resistance in sheep worms has been recognised as a widespread problem in Western Australia (WA) since the 1980s.