Article by Paul Doran MA, VetMB, MRCVs.
In June this year, the Steering Group of the Bovine TB partnership for England published new recommendations for the bTB control strategy for England. This received some interest but has then been a little overshadowed by more pressing concerns such as the prolonged dry weather, heat stressed cattle, heat stressed farmers and the alarming rise in Bluetongue cases throughout the UK.
The steering group includes representatives from APHA, Defra, the British Cattle Veterinary Association, scientific experts and cattle farmers. Both the full document and a summary can be found on the main page of the TB Hub website: https://tbhub.co.uk/
bTB is rarely a subject greeted with huge enthusiasm. The epidemiology of the disease can be fascinating, but dealing with the practicalities is frustrating. Given the stress, extra work and financial burden that bovine TB control creates for cattle farmers, and its high prevalence in the South West, it’s often hard not to feel powerless about the situation.
I was therefore pleased reading the new strategy recommendations, to find many to be refreshingly sensible. Although cattle vaccination still appears to be viewed as the ‘holy grail’, there are a range of more immediately implementable recommendations as summarised below:
Herd Risk Scores
APHA produces a monthly TB risk score for every cattle herd in England, but this is not currently published or shared with farmers. It’s suggested the risk scores could be shared privately with farmers in the first instance to help them understand and manage risk and later be made publicly available to inform risk-based trading.
Managing Infection in persistently infected & high risk herds
It’s suggested the testing regime which allows a herd to regain Officially Bovine TB-Free status should be altered for persistently infected herds, utilising more sensitive testing to reduce spread of infection through cattle movements & sales once these herds become unrestricted.
Resolved IRs
Resolved inconclusive reactors (IRs), must continue to remain restricted to the holding for life as is currently the case. The group recommend removing the option to lift restrictions from these animals via interferon-gamma blood testing. Farmers should be encouraged to manage resolved IRs out of the herd e.g. by sending to slaughter as soon as practical.
Use of Ancillary Tests
Several methods of testing for TB aside from the skin test and interferon-gamma tests exist. No test is perfect, but these tests have potential to better assess individual animal risk and support herd management, in a similar way to how Johne’s disease testing has been used to reduce prevalence in the national herd.
Use of these tests is heavily restricted as they can only be used under license from APHA in herds currently under restriction. The testing is done at the farmer’s expense and any positive to animals must be culled from the herd promptly. Consequently, there is little appetite for use of these ‘ancillary tests’ despite their potential.
The strategy recommendations outline a plan for a scheme whereby rules around this testing could become less restrictive, making it more practical to implement.
Cattle Vaccination
There is discussion of the urgent need to overcome the remaining hurdles to implementing cattle vaccination alongside a skin test that differentiates infected from vaccinated animals (DIVA). The suggested goal is to be in a position to deploy cattle vaccination by 2030.
It’s s recommended that initial roll-out of vaccination should focus on high risk areas.
Greater flexibility of TB testing intervals in proportion to risk
Increase the capacity and practicality of AFUs and other biosecure routes to slaughter
Enhanced movement testing to protect farmers from inadvertently buying in infection
e.g. export interpretation of the skin test (there must be no bovine reaction at all for an animal to move) – to be used in high risk situations.
Clearer and more rapid support from APHA at breakdown disclosure
Farm level data, local epidemiological information and guidance on case management & biosecurity being made rapidly available to farmers & their private vets
Adopt a more locally responsive TB control system (rather than always a blanket policy for large geographical areas)
Wildlife Control
It’s recommended that use of badger vaccination is expanded and that surveillance for TB in both badgers and deer is improved. It’s also recommended that implementation of practical and low cost biosecurity measures to reduce risk of wildlife to cattle transmission are continually encouraged.
Conclusion
Many of these recommendations encompass common-sense ideas that have been discussed or suggested by both farmers and private vets for some time so it’s refreshing to see them in a published list of recommendations. The question that remains now is how long we might reasonably be expected to wait before the recommendations start to be implemented.
The government’s aim is for England to achieve Officially Bovine TB-Free status by 2038 which is unlikely to be achieved by continuing as we are so change is desperately needed.
