WA Livestock Disease Outlook

Recent disease investigations

Sheep losses in the South-West due to pregnancy toxaemia

A vet investigated ewe deaths (2%) and illness (2%) in a large breeding flock.
Sheep that died were in good condition in late pregnancy or with 2-week-old lambs.
The sheep were found weak, lying down and died within a day or two.
Blood and tissue samples were tested to find the cause of the sheep deaths and to rule out exotic diseases that cause multiple sheep deaths such as peste de petits ruminants.
Pregnancy toxaemia was confirmed as the cause. Pregnancy toxaemia occurs more commonly in ewes carrying multiple foetuses and is due to insufficient nutrition in late pregnancy.
With continuing dry weather and poor availability of green feed, producers with breeding flocks are advised to supplement feed and consult a vet to treat sick animals.
Read more on pregnancy toxaemia [1].

Abortions and stillbirths in a South-West beef herd

A total of 14 late-term abortions and stillbirths occurred in a herd of 380.
The animals had been drenched with selenium but no regular monitoring of selenium in the blood to prevent under- and over-supplementation had been carried out.
Laboratory testing showed selenium deficiency was present.
Selenium is an important mineral in maintaining pregnancy and a deficiency can also cause low productivity, infertility and retained foetal membranes in adult cattle, and poor growth and a reduced ability to mount an immune response in young cattle.
Testing of these cows supported Western Australia’s freedom from the exotic disease, Brucella abortus, a significant cause of abortion overseas.
Read more about selenium deficiency in cattle [2].

Death at a sheep feedlot attributed to listeriosis

A mature ewe in a feedlot was found lying down with its neck flexed downwards and balance problems.
The vet submitted the sheep’s brain for laboratory examination, which found the presence of the bacteria Listeria monocytogenes, which had caused encephalitis.
Rough feed can cause cuts and sores in the mouth through which bacteria enter. The bacteria may be present in the environment or in poorly prepared silage. Management of these factors helps to reduce the likelihood of infection with listeria.
Testing of the brain also ruled out a transmissible spongiform encephalopathy (TSE).
TSEs are exotic to Australia and there is a national testing program [3]to support producers and vets in ruling out this condition, which can cause neurological signs similar to Listeria infection.

In winter, be on the lookout for:

Disease	Typical history and signs
Cobalt and vitamin B12 deficiency	High rainfall and sandy soils can result in low levels of cobalt in pasture. Ruminants need cobalt in order to synthesise vitamin B12. Stock agisted in the South West that originated further north may not have been routinely treated for cobalt deficiency in the past and may be particularly susceptible to deficiency in winter and early spring. Signs in growing cattle and sheep include anaemia, illthrift and scaly ears. Cattle may have a rough, pale coat and may eat unusual, non-feed items. Sheep are more susceptible and may also have weepy eyes and produce small lambs. In areas with high rainfall and sandy soils, a vitamin B12 response test in animals showing visible signs can help to identify deficiency. Read more about cobalt deficiency in sheep and cattle [4].
Mastitis in sheep	Most common in ewes raising multiple lambs or high milk producing breeds, including Poll Dorset and Suffolk. Signs can range from mild to severe. Cross-suckling of affected ewes may spread infection and cause pneumonia in lambs. Report signs of mastitis in addition to lamb deaths, conjunctivitis and arthritis to your vet for testing for the exotic disease contagious agalactia. Read more about mastitis in sheep [5].
Coccidiosis in young stock	Cases seen in young stock that have not been exposed to the parasite previously. Most common in lambs when feed is in short supply following cold conditions. Signs include diarrhoea, dehydration, poor appetite and poor growth. Coccidia are shed in faeces which can build up in the environment and reinfect other animals, especially if they are housed in close contact. Good management and hygiene especially where stock congregate can help to reduce infection. Read more about coccidiosis in sheep and goats on the Wormboss [6] website.

Updated information on Johne’s disease in cattle and J-BAS

The Department has updated webpages on Johne’s disease in cattle [7]and the Johne’s Beef Assurance Score [8]. If you need more information, contact your nearest Department vet [9]or email Bruce.Twentyman@agric.wa.gov.au [10].

Keep up to date with livestock biosecurity with Fit to trade bulletin

The Fit to trade [11] bulletin promotes government, industry and producer partnership across the biosecurity systems that protect and enable WA's livestock businesses to trade into domestic and international markets. The bulletin is produced by the Department of Primary Industries and Regional Development. To view the current edition or to subscribe, go to agric.wa.gov.au/newsletters/ftt [11].

Disease investigations – beneficial for you, essential for industry

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 affect trade. The WA livestock disease outlook for producers [12]summarises recent significant disease investigations by Department of Primary Industries and Regional Development vets and private vets. Data from these investigations provide evidence that WA is free from these diseases and supports our continuing access to markets.

Previous issues

Previous issues of WALDO - for vets and WALDO - for producers are available on the newsletter archive page [12]or by searching 'WA livestock disease outlook'.

Feedback

We welcome feedback. To provide comments or to subscribe to the monthly email newsletter, WA livestock disease outlook, email waldo@agric.wa.gov.au [13].