Providing practical information to help you protect your farm from biosecurity risks

Don’t ‘shut the gate’ on biosecurity

May 5, 2011

Grass covered fenceRecovery and biosecurity

For the first time in many years, a green tide of grasses and shrubs covers inland eastern Australia. However, the floods and rains will bring on a range of pests and diseases that farmers and land managers have not seen for a long time and will need to deal with.

Most farmers with livestock will prioritise their fences first, for good reason: fences not only keep animals in, they are also there to keep animals out, especially straying stock and feral animals.

NSW Department of Primary Industries veterinary officer Greg Curran believes that attention to farm biosecurity is the key.

“Simple biosecurity measures such as checking the disease background of re-stocker animals, temporary quarantining and monitoring of new or returning stock, and regularly checking pastures and animals in the paddock are essential for a full flood recovery.”

Greg Curran identifies a number of other areas where graziers can consider biosecurity measures:

Livestock purchasing - Vendors offering restocker animals for sale should complete and sign an Animal Health Statement for each consignment.

Worms - If buying or agisting sheep and cattle from cooler areas, they are likely to have worms and those worms may be resistant to some drenches. Get veterinary advice on a drenching plan.

Mosquito-borne diseases – Receding flood waters boost mosquito numbers and they can cause a range of viral diseases in animals. Greg advises producers to keep an eye out for bovine ephemeral fever or three day sickness and to consider vaccinating valuable breeding animals.

Footrot – The introduction of infected sheep into a clean flock can lead to infection. Warm wet conditions in green pasture can make the disease develop further so it is important to carefully inspect all sheep introductions.

Lice – Lice can be introduced through newly purchased or agisted animals as well as stray stock crossing damaged boundary fences. Inspect purchased sheep carefully and consider treatment before them mixing with uninfected flocks. Inspect all sheep regularly for infestation.

Bovine and ovine Johne’s disease (BJD and OJD) – Be aware of exclusion zones and where purchased or agisted stock have come from. Assess the risk of OJD and BJD before purchasing or agisting.

National Livestock Identification System (NLIS) – Recognise and comply with NLIS when moving cattle and sheep.

Diseases – Cattle can be infected with diseases such as vibriosis and BVDV without showing any obvious signs. Sheep might carry ovine brucellosis. Other major diseases include: blackleg, tetanus, pulpy kidney, leptospirosis and botulism.

Weeds and poisonous plants – Alongside the mass emergence of grasses and other edible herbage, there will be a wave of weeds to contend with. These include poisonous plants and noxious weeds, including new species, which arrive via seeds in floodwaters or on livestock.

Constant monitoring of rangeland pasture composition to identify the level of undesirable plants is required, as is monitoring livestock for signs of ill-health.

Plants like fireweed, parthenium weed, St John’s wort, Noogoora burr, lantana, castor oil plant, mother of millions and green cestrum can all cause losses. Even heavy lush growth of some pasture grasses can cause stock losses from nitrate or prussic acid. Movement restrictions and disease implications need to be considered when agisting stock.