Radial and contiguous testing of cattle herds

Radial testing in the Low Risk Area of England

Radial testing diagram - Bovine TB

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 are identified and required to undertake an immediate radial test of all cattle on the holding aged 42 days and older. The radial testing regime is also 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.

Cattle keepers receive a test notification letter from the Animal & Plant Health Agency (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 the test notification letter.

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 is placed under movement restrictions as per standard procedures. Normal overdue procedures also apply for radial tests, and movement restrictions are placed on the herd if the test results are not received by the Animal & Plant Health Agency (APHA) by the latest due date of the testing window.

Radial TB tests are paid for by the government.

The radial testing regime requires that eligible herds complete three additional skin tests:

 

  • 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 revert to their normal frequency of routine surveillance testing.

Yes. Herds undergoing radial testing are notified in writing by the Animal & Plant Health Agency (APHA) of the change to their unit monitoring regime (UMR), from four-yearly testing to annual testing, for the duration of the radial testing regime. This means that pre-movement testing is required while the UMR of a herd is annual testing. Farmers are given a period of four 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 LRA that are already on an annual surveillance testing due to management or type of premises (e.g. bull hiring premises) continue to require pre-movement testing during the radial testing period.

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

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 the normal frequency of 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 the Animal & Plant Health Agency (APHA) following review of the RAD12 test results.

Radial testing in the Edge Area of England 

Radial testing diagram - Bovine TB

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 annual testing sections of the Edge 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 annual 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 are 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 is also 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.

Cattle keepers receive a test notification letter from the Animal & Plant Health Agency (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 the test notification letter.

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 is placed under movement restrictions as per standard procedures. Normal overdue procedures also apply for radial tests, and movement restrictions are placed on the herd if the test results are not received by the Animal & Plant Health Agency (APHA) by the latest due date of the testing window.

Radial TB tests are paid for by the government.

The radial testing regime requires that eligible herds complete two additional skin tests:

 

  • 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.

 

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

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

From 1 January 2018, TB breakdowns with lesion and/or culture positive animals located in the following annual testing counties and part counties trigger radial testing:

 

  • Buckinghamshire
  • East Sussex
  • Leicestershire
  • Northamptonshire
  • Nottinghamshire
  • Berkshire (excluding the area of west Berkshire which is on six-monthly surveillance testing)
  • Derbyshire (excluding the area of west Derbyshire which is on six-monthly surveillance testing)
  • Hampshire (excluding the area of north-west Hampshire which is on six-monthly surveillance testing)

Contiguous testing in England

CON tested farm diagram - Bovine TB

Contiguous testing is carried out to check that infection hasn’t spread from a TB breakdown with lesion and/or culture positive animals (the index herd) to other cattle herds in the locality. All cattle herds, and also goat and camelid herds, which have been grazed or housed in the locality of the index herd are considered by the Animal & Plant Health Agency (APHA) for contiguous testing. Depending on when the index herd was tested before the breakdown started, herds that were in the locality in the previous summer grazing or winter housing period may be eligible for contiguous testing.

Contiguous testing is mainly used in the High Risk Area (HRA) instead of radial testing which is used in the Edge Area and Low Risk Area (LRA). It is also applied to herds that qualify for annual surveillance testing in six-monthly testing parts of the Edge Area.

In the High Risk Area (HRA), contiguous testing is applied to all herds in the locality of the index TB breakdown to check that infection hasn’t spread to local cattle herds. As TB is considered to be endemic in wildlife in the HRA, identifying spread to other neighbouring herds isn’t as critical as it is in lower incidence areas, so a smaller 1km radius from the index farm and associated land boundaries is normally used, compared with 3km for radial testing.

In six-monthly testing parts of the Edge Area, herds in the locality of the index TB breakdown are assessed and if they are on annual surveillance testing (i.e. they satisfy the criteria for earned recognition), then they are eligible for contiguous testing. Herds on six-monthly surveillance testing are not usually required to undergo contiguous testing due to the high frequency of surveillance testing, however the Animal & Plant Health Agency (APHA) may test in exceptional circumstances.

Cattle keepers receive a test notification letter from the Animal & Plant Health Agency (APHA) informing them that their herd requires an immediate contiguous test, specifying the date by which the test is due. The testing window usually starts upon receipt of the test notification letter.

Herds are not routinely placed under movement restrictions whilst undergoing contiguous 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 is placed under movement restrictions as per standard procedures. Normal overdue procedures also apply for contiguous tests, and the herd is placed under movement restrictions if the test results are not received by the Animal & Plant Health Agency (APHA) by the latest due date of the testing window.

Contiguous TB tests are paid for by the government.

Cattle holdings identified by the Animal & Plant Health Agency (APHA) for contiguous testing need to have an immediate TB test of all cattle aged 42 days and older. If the herd has recently completed a whole herd test with negative results, or is due to have a herd test soon, the contiguous test won’t be required.  

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

After a clear contiguous test, the herd returns to its routine frequency of surveillance testing.