What is a radial test?

This is a targeted TB surveillance skin test carried out on cattle holdings around all new TB breakdowns with lesion and/or culture positive animals identified in the Low Risk Area.

The purpose of the test is to check for spread of TB to neighbouring cattle herds and to ensure that any undetected source of infection in the locality is identified, thus supplementing the routine surveillance testing regime in those herds.

All cattle holdings falling within, or straddling, a 3 km radius circle from the new (‘index’) TB breakdown farm will be identified and required to undertake an immediate radial test of all the cattle on the holding aged 42 days or older. The radial testing regime will also be applied to cattle herds that are outside of the 3 km radius circle that have had regular direct or indirect contact with holdings within the 3 km radial testing area.

Radial TB tests are paid for by the government.

How will I know if my herd is required to undertake radial testing?

Cattle keepers will receive a test notification letter from APHA informing them that their herd requires an immediate radial test, specifying the date by which the test is due. The testing window for this immediate radial test usually starts upon receipt of this test notification letter.

Will my herd be placed under movement restrictions whilst the required radial testing is completed?

Herds are not routinely placed under movement restrictions whilst undergoing radial testing. However, if an inconclusive reactor or reactor is disclosed at a TB test, or lesions suspicious of TB are found in an animal sent to slaughter (known as a slaughterhouse case), then the herd will be placed under movement restrictions as per normal APHA procedures. Normal overdue procedures also apply for the radial tests and restrictions will be issued if the test results are not received by APHA by the latest due date of the testing window.

What is the testing window for a radial test?

60 days.

What does the radial testing regime involve?

The radial testing regime requires that the eligible herds complete three additional skin tests as outlined below:

  • immediate radial test (RAD): this test is carried out after receiving the test notification letter from APHA, unless a whole-herd test has been completed with negative results within the 60 days before or after the index case (in such cases, the initial radial test is waived and a RAD6 test is scheduled for six months from the date of the last whole herd test).
  • RAD6 test, carried out six months after completion of the immediate radial test.
  • RAD12 test, carried out twelve months after the RAD6 test.

Thereafter, and provided all the tests are completed with negative results, herds will revert to their normal frequency routine surveillance testing.

Are herds undergoing radial testing subject to pre-movement testing?

Yes. Herds undergoing radial testing are notified in writing by APHA of the change to their unit monitoring regime (UMR), from 4-yearly-testing to annual testing, for the duration of radial testing regime. This means that pre-movement testing will be required while the UMR of a herd is that of annual testing. Farmers are given a period of 4 weeks from the date of the test notification letter from APHA to make arrangements, if needed, prior to commencement of the requirement for pre-movement testing.

Herds in the low risk area that are already on an annual UMR due to management / type of premises (i.e., bull hiring premises or dairy holdings that commercialize raw drinking milk) will continue to require pre-movement testing during the radial testing period.

Can a radial test count as a pre-movement test?

Yes, provided it has been carried out at the right time (i.e. in the 60 days before the date of animals’ movement).

A TB breakdown (with lesions and/or culture positive animals) occurs in a herd which is in the Edge area. This index TB breakdown is within 3km of some holdings in a low risk area (LRA). Will these holdings in the LRA be subject to radial testing?

Yes, this breakdown will trigger radial testing of herds located in the low risk area (LRA).

What happens if all the radial tests have been carried out on my herd without any reactor or inconclusive reactors disclosed?

In this case, after the RAD12 has been carried out, the unit monitoring regime (UMR) of the herd will revert to its original one, resuming normal frequency routine surveillance testing. The requirement for pre-movement testing in those herds that were not subject to pre-movement testing prior to the radial testing regime will also cease to apply. These changes are notified in writing by APHA following review of the RAD12 test results.