Choosing the Right BCG Vaccination Strategy for Bovine Tuberculosis Control

BCG vaccination can play an important role in controlling bovine tuberculosis (bTB) in infected herds, but its success depends on selecting the right vaccination strategy. The choice should be based on disease prevalence, herd management, production system, and clearly defined control goals. A thorough epidemiological assessment before implementation helps veterinarians choose the most appropriate approach for each herd^1,2. 

Begin with Herd-Level Planning 

Vaccination strategies should be tailored to individual herd conditions. Herds with high disease prevalence may benefit from vaccination to reduce infection pressure, whereas herds aiming to make "test-and-slaughter" economically feasible may require a longer vaccination program¹. 

Vaccination should always have defined objectives. Rapid disease reduction may require combining vaccination with measures such as voluntary culling, while gradual prevalence reduction may require vaccination over several years¹. 

Selecting the Appropriate Vaccination Strategy 

Whole-Herd Vaccination 

Whole-herd vaccination involves vaccinating all animals initially, followed by routine vaccination of replacement calves¹. 

Although vaccination does not cure infected animals, it does not worsen disease either³. In healthy cattle, it helps reduce lesion development, bacterial load, and disease transmission. Routine calf vaccination should continue between three and five months of age, with earlier vaccination considered in high-risk herds. Protein boosting after vaccination and revaccination after one to two years can further strengthen protection⁴. 

Vaccination of Heifers 

In dairy systems where calves are reared separately, infection risk increases when pregnant heifers rejoin the adult herd before calving. 

Vaccinating heifers with BCG followed by a cultured protein filtrate (CPF) booster two to three months before calving aims to maximize immunity during this high-risk period. Both BCG and CPF have been shown to be safe for pregnant heifers and their fetuses¹. 

Calf Vaccination 

Calf vaccination is suitable for herds pursuing gradual, long-term tuberculosis control. 

Vaccination can begin between five and six months of age, or earlier if infection risk is high. A protein booster one to two months later, and another before first calving if required, may enhance protection¹. 

Practical Clinical Insights 

The success of any vaccination strategy depends on integrating vaccination with good herd management. Veterinarians should establish clear control goals, regularly reassess herd disease status, and consider measures such as voluntary culling and ongoing monitoring to improve long-term outcomes. 

Take-Home Message 

There is no universal BCG vaccination strategy for every herd. Whole-herd, heifer, and calf vaccination each serve different management objectives. Selecting the strategy according to herd epidemiology, production practices, and long-term disease-control goals can help veterinarians achieve more effective and sustainable bovine tuberculosis control. 

Reference 

1. Milián-Suazo F, González-Ruiz S, Contreras-Magallanes YG, Sosa-Gallegos SL, Bárcenas-Reyes I, Cantó-Alarcón GJ, Rodríguez-Hernández E. Vaccination strategies in a potential use of the vaccine against bovine tuberculosis in infected herds. Animals. 2022 Dec 1;12(23):3377. https://www.mdpi.com/2076-2615/12/23/3377 

2. Buddle BM, Vordermeier HM, Chambers MA, de Klerk-Lorist LM. Efficacy and safety of BCG vaccine for control of tuberculosis in domestic livestock and wildlife. Frontiers in veterinary science. 2018 Oct 26;5:259. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2018.00259/full 

3. Buddle BM, Shu D, Parlane NA, Subharat S, Heiser A, Hewinson RG, Vordermeier HM, Wedlock DN. Vaccination of cattle with a high dose of BCG vaccine 3 weeks after experimental infection with Mycobacterium bovis increased the inflammatory response, but not tuberculous pathology. Tuberculosis. 2016 Jul 1;99:120-7. https://research.aber.ac.uk/files/38968834/buddle2016.pdf 

4. Parlane NA, Shu D, Subharat S, Wedlock DN, Rehm BH, de Lisle GW, Buddle BM. Revaccination of cattle with bacille Calmette-Guerin two years after first vaccination when immunity has waned, boosted protection against challenge with Mycobacterium bovis. PLoS One. 2014 Sep 2;9(9):e106519. https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0106519&type=printable