Biosecurity for sheep owners
Part of biosecurity is maintaining freedom from diseases and pests that do not currently exist on a property.
Not all diseases can be easily prevented, particularly those spread by wind or water. However, having a biosecurity plan can reduce the risk of diseases entering and impacting production on your property.
Sheep arriving on the property
Introducing sheep does present a disease risk. Sheep can carry a range of diseases despite appearing healthy. Examples include external and internal parasites, as well as a variety of noxious weed seeds.
Obtaining animals that have the least disease risk must be a primary aim when buying sheep. Diseases such as footrot or Johne’s disease have the ability to seriously disrupt the enterprise. The risk associated with buying infected sheep cannot be totally eliminated. However, it can be significantly reduced by making careful enquires and obtaining a sheep health declaration from the seller.
Isolating introduced sheep
Introduced sheep should be isolated from other sheep (and livestock) until they are determined to be free from diseases or pests. Depending on the disease risk, this can take 80 days or more. Moving introduced sheep around the property to the yards and woolshed should be planned to occur after other livestock. This will minimise the risk of disease spread to the ‘home’ animals.
Isolating rams
In the case of rams introduced for breeding, the isolation period will generally be short. Additionally, the risk of introducing disease with a small number of stud rams is generally less than with larger mobs of ewes or wethers.
Rams can be sourced from studs that have biosecurity plans in place and have accreditation for Johne’s disease and ovine brucellosis. This provides increased confidence that purchased animals will be healthy.
Isolating stray sheep
Stray sheep found on your property should be removed from the flock and isolated immediately.
Avoid returning stray animals to a neighbouring paddock unless you are certain they belong there. Incorrectly returning animals can increase biosecurity risks and affect your neighbour’s disease status. Locating the correct owner can also create an opportunity to discuss and resolve boundary fencing problems.
If disease is present
If a pest or disease has been introduced, seek professional advice to prevent spread and minimise damage from the incursion.
Visitors, vehicles and machinery on your property
The entry of people, vehicles and agricultural equipment also carries a risk of disease and weed seed introduction.
Clearly visible biosecurity signs can be placed at property entry points. These help to ensure that all visitors check in at the house or office before entering livestock areas.
Disinfecting footwear and wearing clean outer clothing should be routine practice for anyone entering the property. This is particularly critical for anyone who may have attended other farms and had contact with other livestock.
Disinfection procedures are generally not necessary for visitors whose sole purpose is a social visit to the family home. If visitors need to have contact with livestock, biosecurity measures can be implemented.
Vehicles and machinery coming onto the property should be cleaned prior to arrival. Vehicles not required for farm work should remain at the residence. Travel around the property should instead be undertaken in designated farm vehicles.
Footrot
Footrot can remain dormant in the feet of sheep for long periods, especially during dry weather conditions. New sheep should remain in isolation until they have passed through a suitable footrot expression period. This is typically in spring or autumn, when signs of the disease are most likely to appear.
The feet of sheep intended for purchase should be examined. Pay particular attention to misshapen, deformed or recently pared hooves. The prior history of the sheep should be established, as well as any previous foot bathings, treatments or vaccinations. Always request a sheep health declaration prior to purchasing sheep.
Sheep lice
The first signs of sheep lice may not become apparent for 6 months or more after they arrive on your property.
Introduced sheep should be thoroughly checked for lice. If evidence of infestation is found, an effective chemical treatment should be applied. Always request a sheep health declaration prior to purchasing sheep.
Johne’s disease (JD)
JD is an incurable wasting disease that may take years after infection before the first signs of ill thrift and deaths are seen.
Introduced sheep pose the greatest risk of introducing JD on to a property. For this reason it is vital that proposed introductions come from flocks at low risk of JD. A sheep health declaration provides information on SheepMAP accreditation and/or Gudair vaccination history.
Drench resistance
On arrival, sheep should be drenched with an effective chemical and moved to an isolation area. This will limit the risk of introducing drench-resistant worms to your property. It is recommended to do a faecal egg count 14 days post-drenching to check that the product used was effective.
Noxious weeds
Weed seeds such as Patterson’s curse and Bathurst burr are just 2 of the common noxious weeds that may be carried in a sheep's fleece and spread to new areas. Their seasonal germination can mean they may only become obvious weeks or months after introduction. Noxious weeds can be difficult and costly to control if they establish on a property.
For more information see Invasive plant classifications.
The isolation area
The isolation area for new arrivals should have adequate fencing to ensure containment of isolated sheep. Location is important to minimise contamination of other paddocks and travel to and from the woolshed and yards.
By using isolation areas and planned livestock movements, it is possible to confine disease or pests to a specific area. This area could be either cropped or grazed by species not affected by the disease. This should continue until the outbreak is controlled or sufficient time has elapsed to ensure that the disease agent no longer poses a risk.