Cattle Industry Funding Scheme: Annual Report 2013/14

2013/14 biosecurity programs

Contributions collected via the Cattle IFS were used for a surveillance program to maintain Western Australia’s ‘area of freedom’ status for bovine Johne’s disease in cattle herds and enzootic bovine leucosis in licensed dairy cattle herds, as well as providing funding for the laboratory testing required for surveillance targeting bovine tuberculosis. The programs were delivered by DAFWA at a total cost of $291 403.

Surveillance for enzootic bovine leucosis

Enzootic bovine leucosis (EBL) is an infectious viral disease of cattle, with no known treatment or vaccine available at this time. All Australian States are working toward freedom from EBL. This is primarily due to the perception that milk or dairy products may become contaminated with EBL and this, in turn, may impact on human health.

Under the EBL National Standard Definitions and Rules, to maintain ‘EBL-Free’ status, dairy herds require one negative bulk milk tank EBL test every three years. WA industry has implemented a higher standard of testing. In 2013/14, testing for EBL was carried out for 165 dairy herds, with no EBL detected.

Intensive bulk milk tests were also undertaken on 22 larger (>200 cows) herds. All tests were negative.

Western Australia’s dairy herds continue to maintain a self-declared ‘EBL Provisionally Free’ status. The main risk to EBL Freedom is the introduction of infection from beef herds. Cattle being moved from untested herds require an EBL test before being introduced to a new herd.

Surveillance for bovine Johne’s disease

Bovine Johne’s disease (BJD) is a chronic wasting disease of cattle caused by the bacterium Mycobacterium paratuberculosis. The disease has a long incubation period and is spread by infected animals. BJD reduces production levels even before symptoms are apparent. There is no treatment for BJD.

Western Australia continues to be recognised as a BJD Free Zone. Having a ‘BJD Free’ status enables WA producers to trade within the State and into other Australian States without restrictions. The Cattle IFS-funded BJD surveillance program is essential in providing evidence of Western Australia’s freedom from BJD.

In 2013/14, diagnostic investigations were carried out on 5 animals showing signs of potential BJD infection. For two of these cases, BJD has been excluded in the diagnoses. A definitive faecal culture result is still pending for three animals.

A further 7440 blood tests were carried out on export cattle, with 54 positive or suspect positive results. These cattle were retested, with 27 animals retesting as negative. Laboratory results are still pending for the remaining animals.

Suspect bovine tuberculosis

As a result of testing for bovine tuberculosis on export cattle, one animal reacted to the tuberculin skin test. The animal was slaughtered and the tissues were cultured to determine if it was infected by bovine tuberculosis. The results were negative.

Table 2 Expenses for the 2013/14 disease surveillance program (EBL, BJD and bovine tuberculosis)

Kimberley BJD surveillance program

In late 2012, it was determined that six herds in the Kimberley had received traced bulls from a BJD-infected herd in Queensland. A surveillance program was started in early 2013, which aligned with the national BJD Standard Definitions, Rules and Guidelines, in order to resolve suspicion of BJD in WA.

To date, a total of 308 bulls originating from the infected Queensland stud have been found and tested to determine if any were infected with the disease. One six-year old bull tested positive for BJD and was shedding the bacteria; 292 were negative for faecal shedding on definitive testing; and results are pending for 15 animals. One two-year old bull had evidence of infection, but was not shedding the bacteria. This bull would have posed an infection risk in the future if not culled as part of this program.

Table 3 Ages of bulls traced and tested, and laboratory test results to 21 July 2014

Herd testing, to resolve the disease status of each property, has been completed. A total of 2494 faecal samples were collected and tested. All samples were negative for BJD. Further herd testing will be required on the property with the infected six-year old bull later this year, and all five properties in 2015.

Compensation totalling $5760 was paid during the year to the landholders where animals were slaughtered as part of the surveillance program.

Five properties remained under regulatory restriction at 30 June 2014.

The total cost of the Kimberley BJD surveillance program for 2013/14 was $198 663 (Table 4).

Table 4 Expenses for the 2013/14 Kimberley BJD surveillance program.