WA Livestock Disease Outlook - for producers - April 2016

Supporting Australia's ability to sell livestock and livestock products

Australia’s ability to sell livestock and livestock products depends on evidence from our surveillance systems that we are free of livestock diseases that are reportable or which affect trade. To gather this proof of freedom, the Department of Agriculture and Food, Western Australia (DAFWA) investigates cases where livestock show signs of disease similar to reportable or trade 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 and in 2014/15 allowed WA to access export markets valued at $1.6 billion.

Recent significant cases submitted to the Animal Health Laboratories (AHL)

Case data from mid-February 2016 to mid-April 2016

Transmissible spongiform encephalopathies (mad cow disease - TSE) exclusion

Sudden death and collapse were seen in a mixed age Angus cattle herd in the Mid-West.
Of the 100 in the herd, 13 heavily pregnant animals had died and the remaining 77 were drooling, staggering, aggressive and lying down more than normal with minor body tremors. Two animals had aborted.
Two condition score 4-5 animals underwent post-mortem. The animals were heavily pregnant.
The post-mortem showed yellow gelatinous fat and pale kidneys and livers. The attending veterinarian made a differential diagnosis of lipidosis, ketosis or pregnancy toxaemia.
Due to the nervous signs shown by the animals, DAFWA also tested for TSE, with negative results. TSE testing is subsidised as it supports Australia’s ability to declare freedom from these diseases, which in turn allows us to continue to trade livestock and maintain consumer confidence in livestock product food safety.
Laboratory testing of the samples showed fatty build-up in the liver, which is commonly associated with pregnancy toxaemia. Fatty liver due to pregnancy toxaemia was diagnosed.

Read more on pregnancy toxaemia and on the Subsidised Disease Investigation Pilot Program.

Brucella abortus exclusion in stillborn calves

A Murray Grey herd of 25 animals in the Great Southern had six stillborn calves over two weeks.
One stillborn calf was post mortemed, with the only finding a mild pneumonia. The vet took submitted samples for AHL testing.
Testing was negative for bovine pestivirus and Leptospira cultures. No other significant bacterial infection was detected.
Laboratory testing also excluded Brucella abortus, which supports continuing export markets and public health.
Finding the exact cause of abortion cases can prove difficult. To assist in reaching a diagnosis producers are encouraged to contact their vet early in the course of the disease and save any aborted foetuses, placental material and birth fluids for their vet to sample.
Several diseases causing abortion in animals are zoonoses. (Able to infect humans). All producers should exercise extra hygiene when handling aborted foetuses or aborted material, including wearing gloves and washing hands and tools in soap/detergent.

African horse sickness (AHS) and Hendra virus exclusion in the South West

A six-year-old quarter horse mare had breathing difficulties and swollen tissues of the head, eyelids, cheeks and throat. The next day three other horses on the same property developed similar signs.
Blood samples were taken from all horses before giving supportive treatment to reduce tissue swelling. The treatments started to reduce the tissue swelling overnight.
Clinical examinations of all horses were inconclusive but due to the clinical signs, the differential diagnosis list included Hendra virus, the exotic disease African horse sickness and fescue toxicosis.
Laboratory testing for Hendra virus and African horse sickness were both negative and there was no fescue found in the horse paddocks.
A comprehensive history revealed exposure to cut avocado trees over the past four weeks. Avocado toxicosis was diagnosed. The horses were separated from the avocado cuttings.
Owners are reminded to be aware of their personal safety and of the possibility of Hendra virus when their horses develop breathing difficulties or unusual health signs. Always seek veterinary advice if you spot something unusual.

During late autumn, be on the lookout for:

Below are diseases that occur in WA during autumn that may look similar to exotic diseases that do not occur in Australia. If you see these disease signs, contact your vet for an accurate diagnosis to assist future management of your livestock. This will also enable early detection and control of any new diseases that may occur. Disease investigations by your vet may be eligible for a subsidy from the Subsidised Disease Investigation Pilot Program - see the webpage for more information.

Hypomagnesaemia (grass tetany) in cows:

Commonly affects older beef cows with calves at foot in winter/spring.
Often associated with cold weather, grazing grass-dominated pastures or recent topdressing with potassium (potash).
Affected cattle typically found dead with paddle marks. Earlier signs include aggression, galloping bellowing, muscle twitching, and goose-step gait.

Pregnancy toxaemia or ketosis

Usually affects late pregnant ewes, particularly those carrying multiple lambs
Affected ewe is often separated from the mob
Nervous system signs – body tremors, blindness
Ewe is not eating and appears drowsy or comatose
Death 3–4 days later

Hypocalcaemia in ewes

Ewes in last six weeks of pregnancy and in first month of lactation are most at risk
Rapid onset with muscle trembling and weakness
Ewe sitting on brisket, alert but unable to get up
Death within 24 hours. Often occurs with ketosis

Calf scours

Affects young calves in late autumn and early winter
Signs include depressed appearance, diarrhoea, dehydration, inability to stand and ultimately death

Foot-and-mouth disease – do you know the signs?

One of the diseases that could devastate Australia’s and WA’s livestock industries and the entire regional economy if it entered WA and was not eradicated early is foot-and-mouth disease (FMD).

An Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) 2013 report, which modelled the socio-economic effects of a foot-and-mouth disease outbreak in Australia, a large, multi-state outbreak would cost Australia up to $52 billion over 10 years, with 99% of those losses being direct economic costs of lost export and depressed domestic markets. The larger and longer the outbreak, the increased time it would take to restore markets. As WA exports about 80% of its livestock and livestock products, it is vital that our surveillance strategies target early recognition and detection in order to minimise the impact of a foot-and-mouth disease outbreak.

Producers are a key part of our early recognition of foot-and-mouth disease. Note that the signs of foot-and-mouth disease in sheep can be very subtle and may just appear as transient lameness. To find out more about how to protect WA’s livestock and regional industries by recognising and reporting any signs of foot-and-mouth disease early,

Previous issues and to subscribe

To subscribe to WALDO - for producers or to view previous issues, visit the WA Livestock Disease Outlook newsletter archive page.

Feedback

To provide feedback, email Dr Bruce Twentyman on bruce.twentyman@agric.wa.gov.au.

In this issue

See Also

Regions

You are here

Newsletters

WA Livestock Disease Outlook - for producers