WA Livestock Disease Outlook - for vets

Livestock disease investigations protect our markets

Australia’s ability to sell livestock and livestock products depends on evidence from our surveillance systems that we are free of particular livestock diseases. The WA livestock disease outlook – for vets summarises recent significant disease investigations by Department of Primary Industries and Regional Development (DPIRD) vets and private vets that contribute to that surveillance evidence.

Recent livestock disease cases in WA

Lead poisoning in cattle on two South West properties

In January, two herds of cattle were affected by lead poisoning.
In one case, a mob of 12 yearling Murray Grey steers was moved to a new paddock. The following week, four steers showed acute neurological signs including tremors, stupor, confusion and salivation and then died.
In the second case, four Angus cross cows died from a mob of 110 over a three-week period, with one affected animal showing aimless walking, inappetence and blindness.
In both cases, a vet conducted an on-farm investigation and post-mortem, and submitted fixed and fresh samples to DPIRD. In one case, several old lead batteries were found in the paddock.
Lead toxicoses were confirmed at the DPIRD laboratory, with high levels detected in the kidney and blood.
Both properties were quarantined and the remaining animals cannot be moved until laboratory testing has confirmed they are free of lead residues.
Lead is highly toxic to livestock. Cattle have a high risk of lead poisoning because of their inquisitive nature. They have a tendency to ‘taste test’ items such as old batteries, sump oil, flaking paint, ashes and diesel.
Please remind your clients to check their paddocks for items that could harm livestock health or cause residues. Preventing residues protects our food safety and market confidence in our products.
Read more [1]about how to prevent lead poisoning and residues in livestock.

[2]

[3]

Image 1 and 2: Lead sources that could poison stock such as old or burnt batteries in paddocks or farm dumps should be removed or fenced off.

Blue-green algae poisoning causes deaths in Wheatbelt sheep

In a flock of 300 two-year-old Merino ewes, five died and two were unwell.
The ewes showed acute neurological signs prior to death including paddling, opisthotonus, blindness and muscle tremors of the head and neck.
The flock was grazing oat regrowth, and was up to date with drenching and vaccinations.
The producer contacted their local DPIRD field vet [4], who conducted an on-farm investigation and post-mortem of two animals. There were no gross pathological signs, however a full sample set [5], including a dam water sample, was collected and submitted to DPIRD.
On microscopic examination of the water sample, Anabaena species of blue-green algae were identified, supporting a diagnosis of blue-green algae poisoning.
Blue green-algae growth can be triggered by warm temperatures in shallow, calm water, as well as by excess phosphorus and nitrogen in the water.
See the blue-green algae webpage [6]for more information, including prevention and treatment.
The signs of blue-green algae poisoning can be similar to other livestock diseases that are reportable [7]and may be eligible for subsidised investigation.

In late summer, watch out for these livestock diseases

Disease, typical history and signs	Key samples
Salmonellosis in sheep Heavy worm burdens, water deprivation, high stocking densities and other stressors may precipitate summer outbreaks. Most commonly caused by the S. Typhimurium serovar in WA. Signs can include fever, reluctance to move, profuse, foul-smelling diarrhoea and abortions in ewes. Read more [8]about salmonellosis in sheep.	Ante-mortem: Faeces – 20mL in individual containers. Post-mortem: Liver, gall bladder, abomasum, intestinal sections, lung, intestinal lymph nodes (fixed and fresh).
Vitamin E deficiency/ nutritional myopathy in weaner sheep Most common in growing sheep after a prolonged period without access to green feed. Signs include lameness, ill-thrift and sudden death. Disease is exacerbated with driving and heavy worm burdens. Read more [9]on vitamin E deficiency.	Live sheep pre-treatment: 10mL blood (lithium heparin) from five affected sheep. Post-mortem: Include fixed skeletal and cardiac muscle for histopathology. 10g fresh liver for vitamin E assay.
Bovine anaemia due to Theileria orientalis group (BATOG) BATOG occurs in southern WA where the bush tick, Haemaphysalis longicornis, is found. Infected ticks spread the blood parasite T. orientalis. Only infected ticks will transmit disease. Signs include anaemia, abortion, jaundice, laboured breathing, weakness, collapse. The disease may cause deaths in young stock. Healthy young stock that become infected may develop protective immunity but will continue to carry the parasite. Differential diagnoses: milk fever, leptospirosis, bracken fern or brassica poisoning, copper or zinc toxicity and reportable diseases babesiosis and anaplasmosis. There is no specific treatment, but supportive care is recommended. Read more on the BATOG webpage [10]. Eligible disease investigations can be subsidised [11]– contact your DPIRD field vet officer. [4]	Ante-mortem: 10mL blood in lithium heparin 10mL blood in EDTA Blood smear Post-mortem: Fixed and fresh liver and spleen

Disease, typical history and signs

Key samples

Salmonellosis in sheep

Heavy worm burdens, water deprivation, high stocking densities and other stressors may precipitate summer outbreaks.
Most commonly caused by the S. Typhimurium serovar in WA.
Signs can include fever, reluctance to move, profuse, foul-smelling diarrhoea and abortions in ewes.
Read more [8]about salmonellosis in sheep.

Ante-mortem:

Faeces – 20mL in individual containers.

Post-mortem:

Liver, gall bladder, abomasum, intestinal sections, lung, intestinal lymph nodes (fixed and fresh).

Vitamin E deficiency/ nutritional myopathy in weaner sheep

Most common in growing sheep after a prolonged period without access to green feed.
Signs include lameness, ill-thrift and sudden death.
Disease is exacerbated with driving and heavy worm burdens.
Read more [9]on vitamin E deficiency.

Live sheep pre-treatment:

10mL blood (lithium heparin) from five affected sheep.

Post-mortem:

Include fixed skeletal and cardiac muscle for histopathology.
10g fresh liver for vitamin E assay.

Bovine anaemia due to Theileria orientalis group (BATOG)

BATOG occurs in southern WA where the bush tick, Haemaphysalis longicornis, is found. Infected ticks spread the blood parasite T. orientalis. Only infected ticks will transmit disease.
Signs include anaemia, abortion, jaundice, laboured breathing, weakness, collapse.
The disease may cause deaths in young stock. Healthy young stock that become infected may develop protective immunity but will continue to carry the parasite.
Differential diagnoses: milk fever, leptospirosis, bracken fern or brassica poisoning, copper or zinc toxicity and reportable diseases babesiosis and anaplasmosis.
There is no specific treatment, but supportive care is recommended. Read more on the BATOG webpage [10].
Eligible disease investigations can be subsidised [11]– contact your DPIRD field vet officer. [4]

Ante-mortem:

10mL blood in lithium heparin
10mL blood in EDTA
Blood smear

Post-mortem:

Fixed and fresh liver and spleen

Spread the message about preventing African swine fever (ASF)

ASF is currently spreading across Europe and Asia and poses a major threat to pig-producing countries that are free of the disease, such as Australia. Recent testing by the Department of Agriculture and Water Resources (DAWR) on pork products seized at international airports and mail processing centres over a two-week period revealed that six of 152 products tested were contaminated [12]with ASF virus. This finding demonstrates the risk to Australia from ASF.
Always report any unusual deaths or suspicion of ASF to a DPIRD field vet [4] or the Emergency Animal Disease hotline on 1800 675 888. Early detection = faster eradication. Please share this message with your networks who have contact with domestic or wild pigs, including veterinary colleagues, the pork industry and hunting groups.
Read more on ASF on the DPIRD [13] and the DAWR webpages [14].

WA Livestock Disease Outlook highlights benefits of surveillance

Australia’s ability to sell livestock and livestock products depends on evidence from our surveillance systems that we are free of particular livestock diseases. The WA livestock disease outlook – for vets summarises recent significant disease investigations by DPIRD vets and private vets that contribute to that surveillance evidence.

To provide feedback or to subscribe

We welcome feedback. To provide comments or to subscribe to the monthly email newsletter, WA livestock disease outlook, email waldo@dpird.wa.gov.au [15]