About Bovine TB
Testing & movements
Included in the Government’s comprehensive bTB Eradication Strategy is a commitment to look for opportunities to improve TB controls in cattle. The measures outlined below will ensure better control of bTB risks in the High Risk Area (e.g. through more sensitive testing of TB breakdown herds) and enable us to make faster progress towards achieving Officially TB Free (OTF) status for counties in the Edge Area of England.
1. Wider use of interferon-gamma blood testing in the HRA
Mandatory gamma testing is applied to supplement the skin test and help resolve TB breakdowns with lesion and/or culture positive animals in the HRA where any of the following three criteria are met:
More detailed information about this policy can be found on the TB Hub and to find out more about the gamma test, read the article.
2. Using ‘severe interpretation’ for skin tests on traced cattle
Tracing involves identifying and testing any cattle that may have moved off a new TB breakdown holding before it was placed under movement restrictions. Any cattle that moved off before the application of TB restrictions are traced and, if still alive, TB tested to minimise the risk of disease spread.
To reduce the risk of missing TB infected cattle, TB skin tests for cattle moved from lesion- and/or culture-positive TB breakdown herds are read using ‘severe interpretation’. This is the same interpretation applied in the TB breakdown herds from which those tracings originate. It involves lowering the cut-off point for a positive result, thereby reducing the likelihood of missing infected animals.
More detailed information about using severe interpretation for trace tests can be accessed on the TB Hub.
3. Reducing the risks from inconclusive skin test reactors
If an animal’s skin test result is not clearly negative or positive, the affected animal is temporarily classified as an inconclusive reactor (IR), pending a re-test 60 days later.
All IRs in the HRA and Edge Area (and in TB breakdown herds in the Low Risk Area) that have a negative result on re-testing remain restricted for the rest of their life to the holding in which they were found.
The only permitted off movements for resolved IRs are to slaughter (either directly or via an Approved Finishing Unit).
Alternatively, cattle keepers have the option to seek approval from APHA to carry out private gamma blood testing of resolved IRs at their own cost. If that test is negative, the animal is released from life-long restrictions. If the test is positive, then the animal is compulsorily slaughtered and compensation paid. The holding is placed under TB restrictions and subject to normal TB breakdown procedures and testing.
More detailed information on the resolved IRs policy is available on the TB hub.
4. More effective control of the movement of cattle from one TB breakdown herd to another
For business sustainability reasons APHA will sometimes license the movement of cattle between TB breakdown herds. To reduce the risk of bTB transmission between herds, such movements are only permitted where the destination herd is due to have at least two Short Interval Tests (SITs) at severe interpretation.
More detailed information about movements of cattle between TB breakdown herds can be accessed on the TB Hub.
5. Harmonise the scheduling of short-interval tests (SITs) in TB breakdown herds
A more consistent and rigorous approach was introduced to ensure that in all herds affected by TB breakdowns, the SITs take place at least 60 days after removal of the last test positive (reactor) animals.
More detailed information about scheduling SITs in TB breakdown herds is available on the TB Hub.
6. Edge Area boundaries re-defined by incorporating as whole counties those that previously straddled the High Risk and Edge Areas of England
The counties of Oxfordshire, Warwickshire, Derbyshire, Cheshire and East Sussex, which were previously split between the Edge Area and the HRA, have been fully incorporated into the Edge Area. This has implications for the affected cattle herds in terms of their routine TB surveillance testing frequency (see below) and their eligibility for interferon-gamma blood tests.
More information on the Edge Area changes is available on the TB hub.
7. Six-monthly testing or radial testing extended to all parts of the Edge Area
Six-monthly surveillance testing is applied in Warwickshire, Oxfordshire, Cheshire, the west of Berkshire, northwest Hampshire and west Derbyshire i.e. where incidence of the disease is highest and where radial testing is impractical or administratively complex.
Radial testing around TB breakdowns with lesion and/or culture positive animals is applied in all other parts of the Edge Area, as currently happens in the Low Risk Area.