Making More from Sheep Australian Wool Innovation Limited Meat & Livestock Australia
MODULE 11: Healthy and Contented Sheep
Tool 11.14
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This tool is designed to examine the risks of introducing important diseases that can have major economic consequences for a sheep enterprise.

General considerations to minimise disease introduction:

  • 100% secure boundary fences — most diseases are prevented by secure boundary fences
  • Buying sheep — the more mobs of sheep you buy, the greater the risk of disease, so buy as few mobs as possible
  • Agistment off farm — always quarantine agisted sheep when they return to the home property as they can be exposed to several potential disease sources (roadways, stray or resident sheep on agistment property, trucks)
  • Source of sheep — sheep from properties where regular trading occurs, with poor management or poor fences, are more likely to have disease problems
  • Sheep on roadways, in trucks — may be a risk if you are uncertain of stock movements with neighbours or stray sheep or in trucks (footrot is the major risk)
  • Contractors — equipment or staff may spread diseases such as lice or footrot, if hygiene procedures are not observed.

Specific disease issues:

Thoroughly inspect sheep before purchase and assess relative risk based on trading activities and management. Lice can be difficult to find on sheep for several months after an infestation starts and treatment in long wool cannot eradicate lice. The safest option is to maintain all new sheep on the property in quarantine until they have been shorn and treated after shearing. Then maintain quarantine for the required time after treatment, depending on the treatment (some chemicals do not kill all lice immediately). If shearing and treatment is not possible, maintain them in quarantine for 3 months and check closely for signs of rubbing or wool damage. Shearers need to microwave their moccasins before shearing to kill any lice that may have contaminated them from previous sheds. If you have handled lousy sheep, change clothes before handling clean sheep. Boundary fences are a critical barrier to stop the introduction of lice. Many sheep producers with good boundary fences haven’t dipped sheep for years and have kept their properties lice free, even when neighbours have lousy sheep.

As many sheep as possible should be inspected before purchase, especially lame sheep. Note that previous management, such as foot-bathing and dry seasonal conditions, may mask signs. Purchase sheep with a fully completed National Sheep Health Statement valid / footrot vendor declaration. Seek advice if you are uncertain of footrot symptoms. Place sheep in quarantine on arrival (see tool 11.15). Small numbers of sheep, such as rams, may be inspected several times
before introduction to ewes, but always follow quarantine periods with larger mobs. Footbathing sheep off trucks is only a superficial disinfectant, and will not clear existing footrot infections. The risk of introducing footrot by contamination on boots is small, but if you or others have recently walked over ground where infected sheep have been, it does no harm to scrub boots with a disinfectant such as Hibitane® or Stericide® between properties.

Ovine Johne’s Disease (OJD)

Always buy sheep:

  • With fully completed National Sheep Health Statement
  • From low risk areas
  • With an equivalent or higher assurance based credits (ABC) score.

The more mobs of sheep you buy, the higher the risk of introducing OJD. Current evidence suggests that many flocks are infected with OJD where the owner is unaware of the infection status. The exception is trade lambs, as they are less likely to be shedding bacteria before 12 months of age. Always run older sheep (CFA mob) or cattle on high risk boundaries. Ensure boundary fences are 100% stock proof. Information is available on prevention from your private veterinarian, state government animal health officers, and MLA search the website ( for OJD