Veterinary surgeons in cattle practice are expected to be able to answer the many questions from clients about the suitability of a bovine tuberculosis (bTB) cattle vaccine for their particular farm situation.
Trials of the Bacillus Calmette-Guerin vaccine attenuated strain of Mycobacterium bovis in Friesian-cross cattle in Ethiopia, managed by Cambridge Vet School, have shown a reduction in transfer of infection from co-housed vaccinated and unvaccinated cattle. Together with the application of the detection of infected and vaccinated animals (DIVA), the way is opening for UK herd application. It is indicated that Defra will decide on the way forward, but cattle vets may wish to have a major say.
What do we need to consider when it comes to the future of bTB in the UK?
When it comes to the bTB vaccine, there is some history to consider. In 2010, there was a consultation directed by Defra, where several scenarios to control bovine TB were offered. At the same time, there were mutterings that the options provided had much to do with the requirements of the European Commission and government rather than the needs of farmers. Some veterinary practitioners indicated that a part of one option linked to part of another would be a better way forward. Others revealed that they preferred something else not offered at all.
Years have passed since that consultation, and it is expected that lessons have been learned, particularly that if bovine tuberculosis is a topic of interest to you, then your involvement in the upcoming rollout is required.
bTB testing
One of the first considerations of interest to clients is expected to be the relationship between bTB vaccinations and testing. If the cattle are vaccinated, does routine skin testing stop? No six-monthly herding up in blighted counties. If routine testing stops, what is the attitude of cattle practices? Would a cessation of the current monitoring be welcomed by vets? What is the view of the financial director? Would the practice lose income and reduce staff or possibly be able to engage better with total disease control?
Veterinary views would clarify the level of enthusiasm that can be expected for bTB vaccination from those with direct involvement
Veterinary views would clarify the level of enthusiasm that can be expected for bTB vaccination from those with direct involvement.
The attitudes of all involved
There is expected to be a considerable difference in the attitudes of clients with cattle depending on their business activity. The farmer who only obtains cattle to fatten for slaughter may be more open to vaccination if there is less hassle. National numbers fluctuate, but there will be many more clients with only beef animals rather than dairy or dairy and beef. For particular veterinary practices, the considerations of dairy clients will predominate, while it will be beef for others.
What is the potential for commercial bTB vaccinations?
If 5 million bovines are to be vaccinated each year, will it attract the development of a better vaccine? Possibly a vaccine that is effective where there is an existing infection or one that provides protection for the newborn calf from injecting the dam.
One of the limitations of the control of bTB is the lack of involvement of commercial companies with targeted support for practices. Research indicates that the bTB vaccine would only be part of the overall control of the disease; the DIVA test would show naturally infected animals. A commercial vaccine would change the whole approach and reduce the day-to-day impact of Defra. There are also overseas demands for a vaccine, so the possibility of significant development with bTB appears worthy of scrutiny.
What does this mean for veterinarians?
To answer questions from clients, researchers and the government, cattle vets may need to be fully aware of the current bTB status within their veterinary practice. (See Table 1 for Defra statistics on bTB infected cattle.) How many cattle clients do you have? How many dairy herds? How many beef? How many beef and dairy? And how many individuals in each group are under bTB restriction? Would those clients with a history of restriction welcome the vaccine, and would those clients with a history of disease freedom actually look to vaccinate their cattle? It is probably necessary for the researchers to clarify whether an annual vaccine for all stock on the farm at the same time is a preferred action.
| Year | GB herds | Not TB free | Slaughtered | Tests |
| 2010 | 56,400 | 6,116 (10.8 percent) | 24,600 | 5,367,553 |
| 2023 | 44,681 | 4,535 (10.2 percent) | 20,243 | 7,475,721 |
To answer questions from clients, researchers and the government, cattle vets may need to be fully aware of the current bTB status within their veterinary practice
What is the future of the bTB vaccination and control?
There is the possibility that the future proposal would be the current bTB testing programme plus vaccination. At present, the farmer is not charged for standard testing. Would a vaccine be supplied by the government, free of charge? Does this mean the overall bTB control becomes more expensive to the authorities? If there was a commercial vaccine would clients be prepared to pay for it? Would the continuation or cessation of skin testing be a major consideration?
The DIVA skin test is thought to be equivalent to gamma interferon in detecting infected animals. Further research is due to commence with a full rollout of the tool expected in three to five years. The vaccine is with us now, subject to availability.
It may be that to vaccinate animals going direct to slaughter would be another option, even if the DIVA test is not yet on stream. Is there an animal welfare issue if vaccinated animals develop tuberculosis and pass undetected? Often beef animals to slaughter are not kept beyond two winter housing periods, and a risk assessment may reveal that clinical disease is unlikely. Similarly, would there be an increased risk of human infection with a vaccination and slaughter approach? The option of vaccination with no testing and a direct to slaughter approach may be welcomed by some clients.
Final thoughts
Research results indicating the worthiness of the bTB vaccine are currently available and have opened up a way forward for cattle veterinary practices and their clients. The experience, knowledge and awareness of cattle veterinary surgeons will influence whether the application of new developments rapidly reduces the number of farmers frustrated by bovine tuberculosis.
