Australia's access to markets depends on our surveillance systems
Australia’s access to markets for livestock and livestock products depends on evidence from our surveillance systems that we are free of reportable and trade-sensitive livestock diseases. To gather this proof of freedom, the Department of Agriculture and Food, Western Australia (DAFWA) investigates cases where livestock show signs similar to reportable or trade-sensitive diseases. The WA livestock disease outlook – for producers (WALDO) is collated from information collected by DAFWA and private veterinarians as part of proving Australia’s freedom from those diseases.
Recent significant cases submitted to the Animal Health Laboratories (AHL)
Case data from mid-August to mid-September 2015
Hindlimb gait abnormalities in bulls in the Kimberley
- 60 bulls had been grazing sorghum for about 12 weeks when 15 bulls became unsteady in their hindlimbs.
- The sorghum had recently sprouted green shoots and a new type of silage had been introduced into the diet.
- The local veterinarian examined the affected bulls but found nothing abnormal other than the hindlimb problems.
- The herd was moved off the sorghum and over the next four days the affected animals returned to normal.
- Sorghum and silage samples were submitted for laboratory testing. Possible causes of the disease signs included nitrate/nitrite poisoning; fungal growth in the feed sources; botulism; and cyanide poisoning from the new sorghum shoots.
- Testing revealed toxic levels of cyanide in the sorghum pasture but not in the introduced silage.
- Shooting sorghum is high in cyanide and nitrates and hay prepared from such crops can retain toxic levels. Producers should test any suspect home-grown fodder, hay or silage and ask for a commodity vendor declaration when buying in feed to avoid these types of problems.
Nervous signs and multiple deaths in Merino ewes in the South-West
- 100 four-year-old Merino ewes died on a South-West property which carried a total of a 1000 ewes.
- The ewes had been divided into three mobs and one mob recorded no deaths.
- The affected animals showed nervous signs and appeared disorientated, staggered and then collapsed and died. Some animals had been scouring.
- Veterinary examination revealed the animals had pale gums, poor body scores and an uncertain worming history. The vet carried out a post-mortem on one animal and submitted a basic sample set for laboratory testing.
- Tissue samples showed inflammation in the intestines and the liver and evidence of intestinal worms.
- Blood tests showed damage to the liver and very low blood protein levels.
- A high worm egg count was recorded with 93% of eggs identified as Haemonchus (Barber’s pole).
- To support Western Australia’s continued access to markets, producers should always report high death rates and unusual behaviour in livestock such as the nervous signs above to a veterinarian. Testing of animals with nervous signs in the eligible age range is required to maintain Australia’s access to markets.
- Read more on transmissible spongiform encephalitis (TSE) and the national testing program.
- Producers who have suitable animals autopsied under the TSE program may claim $110 for sheep (GST inclusive) for up to two animals per disease outbreak per property.
- Read more on Barber’s pole worm.
Ill-thrift, scouring and deaths in Merino ewes in the South-West
- Ill-thrift, scouring and deaths were seen in four-year-old Merino ewes, with 10 affected and six dead in a mob of 2000.
- The mob had been drenched approximately two months ago. A veterinarian post-mortemed one animal and submitted samples for laboratory testing with suspicions of a continuing worm problem and/or trace element deficiency.
- Ovine Johne’s disease (OJD) was diagnosed as laboratory testing showed the bacteria responsible for OJD were present and the intestinal system showed evidence of disease that prevents normal digestion and absorption of nutrients leading to diarrhoea and weight loss.
- Worm egg counts were negative in this case.
What happens when ovine Johne’s disease (OJD) is diagnosed on a WA property?
- OJD may be detected on a property as part of a disease investigation into ill-thrift and weight loss.
- In Western Australia, OJD is a reportable disease, but is not regulated. Owners of infected properties are not placed into quarantine or required to destock.
- Since the disease is not regulated, owners are not compelled to do anything, however:
- Owners should inform their neighbours so that they can make their own biosecurity arrangements.
- Owners of infected properties should inform buyers of restocker sheep of their OJD status. The best tool to inform buyers is the National Sheep Health Statement (NSHS): free downloadable PDFs are available on the Farm Biosecurity website at Farm Biosecurity: Declarations and statements.
- There are no public health implications with OJD so trade of animals direct to slaughter can continue as normal.
- Animals sold through saleyards should be accompanied by an NSHS indicating ‘Slaughter only’.
- Vaccination is in most cases the best control option for an infected property, but grazing management and flock structure also play a part.
- The DAFWA website has comprehensive information on prevention and management of OJD.