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-sensitive diseases.

Recent livestock disease cases in WA

Stillborn calves associated with bovine anaemia due to Theileria orientalis group (BATOG) in cows in the Great Southern

In a mob of 12 Murray Grey cows between three and seven years old, five delivered stillborn full-term calves. No other disease signs in the cows were seen.
The producer reported the cases to the local DPIRD field vet [1], who conducted an investigation and post-mortem on the dead calf and submitted samples to the DPIRD laboratory.
The laboratory investigation showed that the cows were anaemic, and all cows tested positive for the blood parasite, Theileria orientalis Ikeda. Examination of the dead calf showed evidence that the dam’s anaemia had caused the stillbirth.
Bovine anaemia due to T. orientalis group (BATOG) was first detected in WA’s Lower Great Southern in 2013 and has also been found in South-West WA. It is spread by the bush tick (Haemaphysalis longicornis).
Cattle under stress are most affected by BATOG. This includes late-pregnant and recently calved cows, aged cows and young calves (2–3 months old).
Calling a vet and obtaining testing to achieve a diagnosis allowed the producer to implement practices to manage this parasite in the herd.
Other infectious causes of abortion, including bovine pestivirus, vibriosis, leptospirosis and infectious bovine rhinotracheitis, as well as the reportable diseases [2]bovine brucellosis, anaplasmosis and babesiosis, were ruled out in the investigation.
Testing was subsidised as the results will contribute to demonstrating WA’s ongoing freedom from these trade-sensitive diseases.
Read more about BATOG [3]and the BATOG surveillance program [4] in WA.

Significant Disease Investigation program funds investigation into sudden death in Merino sheep in Great Southern

In a mob of 220 one-year-old mixed-sex Merinos, 25 were found dead. Some sheep were down and convulsing prior to death. The sheep had been drenched one week prior.
A vet conducted an on-farm investigation and post-mortem and submitted samples to the DPIRD laboratory. The investigation was funded under the Significant Disease Investigation [5] program, which is designed to boost WA’s capacity to detect animal diseases that could impact on trade or regional or national animal health.
Fluoroacetate was found in rumen contents, supporting a diagnosis of fluoroacetate poisoning.
Plants in the Gastrolobium genus containing fluoroacetate (e.g. common box, heartleaf and narrow leaf poison bush) are likely to have highly toxic leaves at this time of year. Poisoning typically occurs when hungry stock gain access to bush or a new area containing the plants, and spring pasture dies and becomes less palatable.
If you see unusual signs or deaths in your stock, contact a private vet or DPIRD field vet [1].

Lumpy skin disease ruled out in cattle in the South-West

Three 18-month-old Charolais cows from a mob of 300 had large wart-like skin lesions on the body (see Image 1).
No other disease signs were reported.
The investigating vet suspected the lesions were fibropapillomas, and sent samples to DPIRD laboratory for confirmation.
Testing confirmed fibropapillomas, and ruled out the reportable disease [2], lumpy skin disease.
In cattle, fibropapillomas of the skin are due to infection with bovine papillomavirus 1, 2 or 5. In this case, the lesions were consistent with BPV-2 infection, which is usually self-limiting and lesions reduce within 12 months.
Lumpy skin disease is a highly infectious disease of cattle caused by a poxvirus exotic to Australia. It is usually transmitted by biting insects. Disease signs include multiple, raised skin lesions, fever, salivation and nasal discharge.
Lumpy skin is a priority disease due to its increasing international distribution and the major impact it would have on cattle productivity if it entered Australia.
[6]
Image 1: Wart-like lesion on the point of the shoulder of an affected cow

Emergency animal disease contacts during the Christmas closure

The Christmas closure date for DPIRD offices are from Monday 24 December 2018 to 1 January 2019 inclusive. If you suspect an emergency animal disease (EAD) during that period, ring the EAD hotline on 1800 675 888.

In late spring, watch out for these livestock diseases

Disease	Typical history and signs
Barber’s pole worm in sheep Read more on Haemonchus [7]	Usually seen in late spring/early summer in coastal areas of agricultural regions of WA. Weaners with inadequate immunity commonly affected at this time of year. Signs include sudden death, anaemia, weakness and bottle-jaw.
Annual ryegrass toxicity (ARGT) Read more on ARGT [8]	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 in September, moving south as the season progresses and as stubbles become available for grazing. Signs include sudden deaths or nervous signs such as hyper-excitability, wobbly gait and convulsions. Always report nervous signs in adult sheep or cattle to your private vet or DPIRD field vet [1], who will collect samples to exclude transmissible spongiform encephalopathies [9] and to determine the cause to assist on-farm management and productivity.

Disease

Typical history and signs

Barber’s pole worm in sheep

Read more on Haemonchus [7]

Usually seen in late spring/early summer in coastal areas of agricultural regions of WA.
Weaners with inadequate immunity commonly affected at this time of year.
Signs include sudden death, anaemia, weakness and bottle-jaw.

Annual ryegrass toxicity (ARGT)

Read more on ARGT [8]

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 in September, moving south as the season progresses and as stubbles become available for grazing.
Signs include sudden deaths or nervous signs such as hyper-excitability, wobbly gait and convulsions.
Always report nervous signs in adult sheep or cattle to your private vet or DPIRD field vet [1], who will collect samples to exclude transmissible spongiform encephalopathies [9] and to determine the cause to assist on-farm management and productivity.

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 livestock diseases that are reportable or affect trade. The WA livestock disease outlook – for producers 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.

We welcome feedback. To provide comments or subscribe to the monthly email newsletter, WA livestock disease outlook, email waldo@agric.wa.gov.au [10].