Biosecurity for sheep producers

Biosecurity means maintaining freedom from diseases and pests that do not currently exist on a property.

While some diseases can be windborne and more difficult to prevent, having a well planned biosecurity strategy will help prevent various production limiting diseases entering your farm.

Sheep arriving on the property

Introducing sheep also presents a risk of disease introduction. Sheep can appear healthy while at the same time carrying a range of diseases, including external and internal parasites, as well as a variety of noxious weed seeds.

Purchasing sheep that have the least disease risk must be a primary aim of farmers 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, but can be significantly reduced by making careful enquires and obtaining a Sheep Health Statement from the vendor.

Isolating introduced sheep

Introduced sheep should routinely be isolated from other sheep until they are determined to be free from diseases or pests. Moving introduced sheep around the farm to the yards and woolshed should be planned to occur after other mobs to minimise the risk of disease spread to the 'home' mobs.

Isolating rams

In the case of rams introduced for breeding, the isolation period will generally be short, and the risk of introducing disease with a small number of stud rams is generally less than with larger mobs of ewes or wethers. By sourcing rams from studs that have biosecurity plans in place and disease accreditation for Johne's disease and brucellosis there is 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.

Lifting strays over a fence into a neighbouring paddock on the assumption that they have originated from that source is not good practice as it compromises your neighbour's disease status if the animals are not from that paddock. Finding the correct owner may also be the ideal opportunity to discuss boundary fencing issues.

If disease is present

If a pest or disease has been introduced, vigilance will help detect it early, so that spread can be prevented and damage of the incursion minimised.

Visitors, vehicles and machinery on your farm

The entry of people, vehicles and agricultural equipment also carries a risk of disease and weed seed introduction. A strategically placed notice, such as on the entry gate of the farm will help to ensure that all visitors check in at the house or office before having contact with stock.

Disinfecting footwear and wearing clean outer clothing should become routine practice for personnel arriving for work on the farm. These measures are particularly critical if workers have been on other farming enterprises and have had contact with other stock.

For visitors to the farm whose primary purpose is a social visit to the family home, disinfection procedures should not be necessary. If visitors need to have contact with stock, biosecurity measures can be imposed.

Vehicles and machinery coming onto the farm should be cleaned prior to arrival. Vehicles not required for specific operations on the farm should be left at the residence and travel undertaken in the farm vehicles.

Footrot

Footrot can remain dormant in the feet of sheep for long periods, especially during dry weather conditions. Ideally, introduced sheep should be kept isolated until they have passed through a suitable footrot expression period, usually a spring or autumn.

Sheep intended for purchase should be examined, paying 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 Statement prior to purchasing sheep.

Sheep lice

The first signs of sheep lice may not become apparent for 6 months or more from the time of arrival on your premises.

Introduced sheep should be thoroughly checked for lice and treated with an effective chemical if evidence of infestation is found. Always request a Sheep Health Statement prior to purchasing sheep.

Ovine Johne's disease (OJD)

OJD 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 OJD on to a property. For this reason it is vital that proposed introductions come from flocks at low risk of OJD. A Sheep Health Statement will provide information about whether the sheep come from a SheepMAP accredited or vaccinated flock.

Drench resistance

Drenching sheep on arrival with an effective chemical and moving them to an isolation area, will limit the risk of introducing drench resistant worms.

Noxious weeds

Weed seeds such as Patterson's curse and Bathurst burr, are just two 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 stock movements, it is possible to confine disease or pests to a specific area. This area could be either cropped or grazed by non-target species until the incursion has been dealt with or a sufficient time period has elapsed to ensure that the disease agent no longer poses a risk.