Bovine TB

Routine herd testing

Routine herd testing is carried out to identify cattle infected with TB and to prevent disease spread to other cattle, other susceptible animals and to protect public health. For Scotland, demonstrating continued freedom from TB is also important to enable trading of cattle with the European Union.

Farmers are required by law to have their cattle tested for bovine TB and APHA advise cattle keepers of their due testing dates. A zero tolerance policy means that if tests become overdue restrictions will be placed on herds which fail to test by the specified testing date.

Compensation payments will be reduced where cattle keepers have allowed their routine herd testing to go overdue by more than 60 days, and TB reactors are subsequently identified.

There is no routine herd testing regime for non-bovine animals. Legislative powers for dealing with TB in specified non-bovine animals (The Tuberculosis in Specified Animals (Scotland) Order 2015) were introduced on the 9 October 2015, but these powers will only be used where disease is suspected or reactor animals identified e.g. at Post Mortem. 

Routine testing intervals

Scotland as a whole has a default testing interval of 48 months. However, in certain circumstances a herd may require more frequent testing and the keepers of these herds are notified on an individual basis. Alternatively, some Scottish herds which have been identified as "low risk" will be exempt from the four yearly routine herd testing and will also be notified separately.

Exempt herds

Following the introduction of a risk based bovine TB testing policy, some Scottish herds were identified as “low risk” and as such were exempt from four yearly routine herd testing.

APHA are responsible for notifying cattle keepers in Scotland whether or not their herd is exempt from TB testing and all herds are reassessed annually. This ensures existing exempt herds continue to meet the low risk criteria and also allows all other herd owners to make the necessary adjustments to their herd management practices in order to be considered low risk and achieve exempt status in the future. All queries relating to this should be directed to the local APHA office.

Low risk criteria

In order to be defined as 'low risk' a herd must comply with one of the following criteria:

• herds with fewer than 50 cattle (total stock on farm at 1st January in the year the herd is assessed) which have had no more than one consignment of cattle moved on from high incidence TB areas (including Northern Ireland and the Republic of Ireland) in the previous four years
• herds that slaughter* more than 25% of their stock annually in each of the previous four years and have had no more than one consignment of cattle moved on from high incidence TB areas (including Northern Ireland and the Republic of Ireland) in the previous four years
• herds that slaughter* more than 40% of their stock annually in each of the previous four years

* Slaughtered animals refers to animals that have been on the holding for at least 60 days that move either direct from farm to slaughterhouse, or direct from farm to market and then direct to slaughterhouse. Animals moving onto another holding temporarily between market and slaughterhouse are not included. The annual slaughter rate is calculated on the total number of cattle slaughtered in that calendar year divided by the herd size on 1st January of that year.

In addition, as there are no dedicated slaughter markets in Scotland, for cattle going to slaughter via market, usual standstill rules will apply.

More information on testing is available on the APHA website.

Slaughterhouse surveillance

All carcases are inspected by the Food Standards Scotland at the slaughterhouse for evidence of TB lesions. Where lesions are found and a carcase is suspected of being affected with TB, APHA will be notified and a restriction notice (TB02) served on the herd of origin. The OTF status of the herd will be suspended (OTFS), pending further investigations.

PCR testing

In February 2024, APHA will extend the use of the polymerase chain reaction (PCR) test to detect M. bovis in post-mortem samples taken from TB test positive cattle, direct contacts (DC), and compulsory or privately slaughtered/dead inconclusive reactors (IR).

A major advantage of PCR testing is it can take only three weeks to get a test result (previously with the culture method this could be up to 22 weeks) and it means movement restrictions can be lifted much more quickly following the veterinary enquiry.

APHA initially trialled the use of PCR testing in suspect slaughterhouse cases in cattle found to have suspicious lesions, and for all post mortems of non-bovine animals which have been compulsorily slaughtered for suspicion of TB. 

Further information about the M. bovis PCR test is available on the TB hub website.

Pre and post-movement testing

In order to protect Scotland’s OTF status, bovine animals being brought into the country from other parts of GB must comply with enhanced pre and post-movement testing control measures introduced under The Tuberculosis (Scotland) Order 2023.

Pre-movement testing

Cattle moving from a high incidence area (HIA) in England and Wales to Scotland (HIA: subject to two yearly or more frequent routine herd testing)

Cattle coming to Scotland from a HIA in England or Wales require a clear pre-movement test within 30 days prior to the movement if tested on or after 18 May 2023 (previously the requirement was within 60 days). This test cannot be carried out while the herd of origin is under TB breakdown restrictions, even if the test allows these restrictions to be lifted.  

Exemptions to the requirement for a pre-movement test are as follows:

• cattle being sent to Scotland directly for slaughter
• cattle moving to shows/exhibitions and returning directly to their farm of origin
• calves under 42 days of age at the time of movement

If the required pre-movement test has not been carried out before the animal arrives in Scotland, the test will be regarded as overdue and movement restrictions will be imposed on the receiving Scottish herd until the test has been carried out. APHA will advise the receiving cattle keeper of the due testing dates for completion of each outstanding pre movement test.

A second (post-movement) test, will also be required for these cattle no fewer than 60 days and no more than 120 days after the first test.

This requirement also applies to cattle which are moving from a premises in the low incidence area, but have lived in the HIA at some point. 

Cattle moving from a low incidence area (LIA) in England and Wales to Scotland (LIA: subject to four yearly routine herd testing)

All cattle over 42 days of age moving to Scotland from a LIA in England and Wales, require a clear pre-movement test within 30 days prior to the movement if tested on or after 18 May 2023 (previously the requirement was within 60 days). This test cannot be carried out while the herd of origin is under TB breakdown restrictions, even if the test allows these restrictions to be lifted. This additional testing requirement was established under the Tuberculosis (Scotland) Amendment Order 2009 and further strengthened by the Tuberculosis (Scotland) Order 2023 as part of the enhanced movements controls in place to protect Scotland’s OTF status.

Exemptions to the requirement for a pre-movement test in a LIA are as follows:

• cattle which can be shown to have spent their whole lives in LIAs
• cattle being sent to Scotland direct for slaughter
• cattle moving to shows/exhibitions and returning directly to their farm of origin
• calves less than 42 days old at the time of movement

If the required pre-movement test has not been carried out before the animal arrives in Scotland, the test will be regarded as overdue and movement restrictions will be imposed on the receiving Scottish herd until the test has been carried out. APHA will advise the receiving cattle keeper of the due testing dates for completion of each outstanding pre movement test.

Post-movement testing

Post-movement tests are required for cattle moving to Scotland from a HIA in England or Wales no fewer than 60 days and no more than 120 days after their arrival in Scotland.

Changes to the post movement testing rules which were introduced on the 12 December 2018 now require that all animals which are eligible to be post movement tested following their arrival in Scotland, should be held on the original premises of destination until this testing has been completed with negative results, before that animal is permitted to move again.

Exceptions to this requirement for post-movement testing are permitted for animals that:

• are slaughtered within 120 days of arrival on the Scottish holding
• are being moved for veterinary treatment
• are being moved under the authority of a licence issued by the APHA

Shows

Cattle moving from Scotland to shows in England or Wales do not require pre- or post-movement testing, and no testing is required at the showground. Despite this, some show organisers may require pre-movement testing to attend a show.  Where this applies, a private TB test would be required at the cattle keeper's expense.

Although there is no legislative requirement for post-movement testing, it is recommended that those who move cattle from Scotland to a show in the High Incidence Area (HIA) undertake a post-movement test upon return to the original premises in Scotland as a precaution. If a post-movement test is undertaken in this instance, it would be a private test and the cost would be met by the cattle keeper.

Farmers moving cattle from England and Wales to a show in Scotland should familiarise themselves with the testing requirements. More information can be found on the TB Hub.

Cattle imported from Ireland to Scotland

Northern Ireland

Importers have to arrange and pay for post-movement testing to be carried out 60-120 days after the animal’s arrival in Scotland unless the imported stock will be sent to slaughter within 120 days of import.

A change to the post movement testing rules which was introduced on the 12 December 2018, now requires all animals that are eligible to be post movement tested following their arrival in Scotland to be held on the original premises of destination until that testing is carried out. The test must be completed within 60-120 days of arrival on farm and with negative results before that animal is permitted to move again. The conditions of the General Import Licence for cattle from Northern Ireland have been amended to support this change.

Republic of Ireland

Cattle will be restricted at their first destination pending a clear 60 day post import test. Any reactor cattle identified at the 60 day test will have to be slaughtered at the owner's expense and no compensation will be paid.

Testing of new herds

New and re-formed herds which source only cattle that have been born and kept in Scotland or other Low Incidence Areas will require one clear routine herd test (breeding bulls, females which have calved, young bovines which will be used for breeding, whether they are home-bred or purchased (except calves under 42 days old)) completed within 12 months of the first animal arriving on the holding before they can move to four yearly testing. Those herds that include cattle born or kept in a high incidence area will require one clear whole herd test (all bovines).

Testing of individual traced animals from confirmed incidents

If an animal has been purchased from a herd that subsequently has a confirmed case of TB, that animal will be tested to check that it has not contracted the disease.

If an animal is sold which is subsequently confirmed to have TB the herd of origin may be tested to check if it contracted the disease prior to sale.

Testing following a TB breakdown

Where there has been a case of TB identified, a series of tests must be carried out to ensure TB infection is cleared from a herd. These skin tests are called short interval tests. Occasionally a blood test – the gamma interferon test, may be used.

Short interval tests usually include all animals in the herd and are carried out at minimum intervals of 60 days. The 60 day period is from the date the last reactor left the herd or from the date any reactors or inconclusive reactors were effectively isolated from the rest of the herd.

The herd will need to pass either one or two consecutive short interval tests following removal of any reactors, including the resolution of any inconclusive reactors by re-testing, depending on whether the TB status of the herd is suspended (OTFS) or withdrawn (OTFW) respectively.

Where herds are OTFW and to ensure the herd is cleared of infection as quickly as possible, severe interpretation is applied at the first short interval test following disclosure of reactors where lesions are detected.

The gamma interferon blood test is a supplementary TB test that may be used in some breakdown situations to improve the detection of infected animals. This test does not replace the tuberculin skin test, which continues to be the primary screening test for bovine TB, but will improve the chances of detecting infected cattle, thereby speeding up the resolution of TB incidents.

After the movement restrictions have been lifted, the herd will have regained its OTF status but may still need to undergo further tuberculin tests to ensure that:

• no infected animals have been missed in previous tests
• no re-infection has occurred

For OTFW herds that have regained OTF status a further skin test is needed 6-12 months later. If the test is negative, the herd will return to its usual routine testing.

Contiguous herd testing

Testing of neighbouring farms around confirmed TB outbreaks will be limited to those where nose to nose contact between cattle is possible. Testing will be carried out as soon as possible and will include all bovines except calves under 42 days old.

Prohibition on testing of bovine animals

The prohibition on testing bovine animals for TB without written consent has now been extended to include any type of diagnostic test for tuberculosis.

Further information

More detailed information on testing can be found in the following:

• dealing with TB in your herd - what happens if TB is identified in your herd?
• University of Glasgow report on risk-based surveillance for bovine TB
• analysis of the results of bovine TB epidemiology and surveillance in Great Britain in 2016