WA Livestock Disease Outlook - for producers

The WA Livestock Disease Outlook provides information about recent livestock disease cases in Western Australia and diseases likely to occur in the next month. Calling a vet to investigate diseases when they occur provides surveillance evidence to our markets that we are free of reportable and trade-relevant diseases.

Biosecurity reminder – African swine fever

Australia remains on high alert in response to the growing number of overseas countries affected by African swine fever, with the latest outbreak confirmed in Indonesia.

In October, a vet submitted samples from the post-mortem of a finisher pig that had a swollen spleen with multiple haemorrhages. Testing ruled out African swine fever and classical swine fever. Producers are urged to contact their vet or the Emergency Animal Disease hotline on 1800 675 888 if they see disease signs in pigs that are similar to African swine fever.

Help keep Australia free of African swine fever – review your biosecurity measures, know what you can and can’t feed pigs, and register your ownership of pigs with the Department of Primary Industries and Regional Development (DPIRD)

For more information on preventing African swine fever and signs of the disease, see the ASF biosecurity webpage.

Recent disease investigations

Cloudy eyes and nose and mouth sores in a cow in the South-West

Cow with malignant catarrhal fever showing an extended neck
Malignant catarrhal fever: neck extension as a result of respiratory distress
Malignant catarrhal fever in a bovine
Malignant catarrhal fever in a bovine: severe exudation from the nostrils ©University of Pretoria. Faculty of Veterinary Science. Dept. of Veterinary Tropical Diseases.
  • A private vet visited a South-West cattle property to investigate a 17-month-old down cow with clouding of both corneas, eye discharge and inflammation, and nose and mouth sores.
  • The cow had been introduced into the paddock three weeks prior and appeared to be the only animal affected in a group of 26.
  • As nose and mouth sores can be signs of the exotic diseases foot-and-mouth disease (FMD) and vesicular stomatitis (VS), the vet submitted blood samples to DPIRD for testing. Testing was negative for both diseases.
  • Where cloven-hooved livestock show these disease signs, ask your vet about the subsidies available or see the DPIRD surveillance incentives webpage. Subsidised disease testing is provided where the results can be used to support Western Australia’s and Australia’s claims for freedom from exotic diseases such as foot-and-mouth disease. The results of this testing supports our ongoing access to markets.
  • The samples tested positive for ovine herpesvirus-2, and given the consistent signs, malignant catarrhal fever (MCF) was most likely to be the cause of disease in the cow.
  • In general, MCF in cattle is caused by either one of two different herpes viruses. Ovine herpes virus-2 is normally carried by asymptomatic sheep and is the most common cause of MCF in cattle in Australia. Alcelaphine herpesvirus-1 is normally carried by asymptomatic wildebeest but causes severe disease in cattle. The wildebeest-associated MCF is exotic and is a reportable disease in Australia.
  • Signs of MCF include cloudy eyes, discharge from the nose, fever, depression, lack of appetite and drop in milk production
  • MCF is not transmitted between cattle, but sheep, particularly young lambs that shed large amounts of virus, should be separated from cattle to prevent transmission of disease.  

Annual ryegrass toxicity (ARGT) season begins

  • A private vet investigated deaths and tremors in a mob of six-month-old Merinos.
  • Seven sheep had collapsed and died after being moved into yards and another 10 sheep were affected with tremors and excessive salivation.
  • Veterinary investigations of sheep affected by neurological disease signs such as tremors may be eligible for subsidies as these investigations provide data that we are free of exotic diseases – see the DPIRD surveillance incentives webpage for more information or ask your vet.
  • A faecal sample was positive for annual ryegrass toxin. This result in conjunction with the disease signs suggested ARGT was the most likely cause of disease.
  • Fresh hay and pasture samples were submitted for quantitative risk assessment and a range of risk ratings from very low to high were detected across samples. The producer was recommended to observe animals on low to moderate risk feed daily and to move those on high-risk feed or paddocks to safe feed sources.
  • Read more about ARGT in the table below.

Neurological signs in five-month-old lambs

Listeria monocytogenes bacterium
Listeria monocytogenes bacterium. Source: CDC Public Health Image Library
  • A producer reported two five-month-old lambs had wobbly gaits, weakness and convulsions. The lambs were in a flock of 450 on mixed pasture.
  • Testing of brain tissue submitted to DPIRD’s laboratories confirmed Listeria monocytogenes infection.
  • Listeria is thought to travel to the brain after entering the body through sores in the mouth.
  • In ruminants, listeriosis takes four main forms: inflammation of the brain or eyes, septicaemia (blood poisoning) or abortions.
  • While spoiled silage is a common source of infection, Listeria can also be found in soil and water. In this case the most likely source of infection was decaying vegetation in the paddock.
  • Listeria monocytogenes can affect a number of species, including humans. Pregnant and immune-compromised people should avoid contact with potentially infected animals and aborted materials.

In summer, watch out for these livestock diseases

Disease, typical history and signs

Haemonchus (Barber’s pole worm) in sheep

  • Usually seen in early summer in coastal areas of agricultural regions of WA.
    • Weaners with inadequate immunity are commonly affected at this time of year.
  • Key signs include sudden death, anaemia, weakness and bottle-jaw.
  • Read more on Haemonchus.

Annual ryegrass toxicity (ARGT)

  • Cases in grazing stock can occur as soon as there is widespread seedset in ryegrass pastures (typically from early October).
  • First cases typically occur in the southern Greenough area, moving south as the season progresses.
  • Infected ryegrass remains toxic even when it has senesced and dried off. Hay made from toxic ryegrass will also be toxic. All grazing animals are susceptible, including horses and pigs.
  • Key signs include sudden deaths or hyperexcitability, lack of coordination and convulsions brought on by stress.
  • Signs of ARGT may appear as soon as four days or as late as several weeks after animals are exposed to toxic feed.
  • Always monitor stock on pasture where ryegrass is present and remove if signs of ARGT appear.
  • When buying hay, always ask for a vendor declaration that states that hay has been tested low-risk for ARGT before buying and have your hay tested before feeding out if it contains ryegrass.
  • Read more on ARGT.

Emergency animal disease contacts during the Christmas closure

This is the final issue of the WA Livestock Disease Outlook for 2019. The next issue will arrive in your inbox in February 2019. Until then, we wish you all a restful and safe holiday break.

DPIRD offices will be closed from Tuesday 24 December 2019 to Wednesday 1 January 2020 inclusive. If you suspect an emergency animal disease during that period, please ring the hotline on 1800 675 888.