25 Mar 2025
Phil Elkins
Job Title
Image: Artem Zakharov/ Adobe Stock
The Cattle and Sheep Health and Welfare Survey by Ruminant Health and Welfare in 2021 listed bovine respiratory disease (BRD) in the top five syndromes affecting cattle production and welfare in the UK, and viral pneumonia in the top five diseases1.
This demonstrates an opportunity for increased veterinary engagement with clients to improve welfare and production. The survey considered both farmers (dairy and beef), and professionals such as vets and advisors. The professionals ranked viral pneumonia as the most impactful disease on production efficiency for the herds they work with; for both classes of farmers it ranked third.
It is clear to see that BRD is an area for potential significant improvement in both welfare, production and client engagement.
Research has shown that the long-term average consequences of treated respiratory disease include the following:
The consequences equate to financial losses of an average of £722 for each dairy heifer treated, around £130 for each beef calf with a moderate case, and around £300 for each severe case2.
These figures are now eight years old, with the current costs likely to be proportionally higher due to increased milk and meat value.
These are the consequences of clinical cases. Subclinical cases will also suffer from reduced growth and performance. Clinical incidence of BRD in a large-scale study was between 11% and 16%, but subclinical incidence was much higher, at 23% to 67%3.
This demonstrates both the variability in severity of clinical signs, and the potential low sensitivity of stock person-identified disease when compared to thoracic consolidation.
The combination of a disease complex with large financial consequences, high prevalence and morbidity, and a low potential sensitivity demonstrates a high potential reward for veterinary intervention targeted at reducing both the incidence and the severity of disease.
While vaccination is far from the only preventive measure, with uptake of vaccination consistently below 40%1, despite BRD being of significant financial cost to the cattle industry, it is clear further steps need to be taken to increase uptake of prevention.
This highlights two areas of further knowledge transfer needed to ensure farmers fully buy in to the benefits of disease control: the impact of mild, or even subclinical, disease and the relevance of specific pathogens on their farm.
A 2016 study found that, in the UK, only 47% of animals at slaughter with severe lung lesions, and 31% of animals with moderate lung lesions, had received treatment for BRD. While this obviously highlights the need for increased and early detection, with prompt, effective treatment, it also shows that for many farmers, they are not aware of the prevalence of pathology, and reduced performance within their herd.
For beef units that finish their stock, this exercise can be repeated at a herd level, with observing for lesions in the abattoir and cross-referencing with both treatment records and performance data to demonstrate the financial impact of untreated disease. For many units, this is not an option – dairy herds, suckler herds selling weaned calves or calf rearers, for example. It also has the issue of a prolonged lag period – the detection of lesions is often long after the disease process. For these situations, thoracic ultrasound scanning (TUS) can be used to demonstrate both the prevalence and the severity of undetected BRD.
Thoracic auscultation to detect consolidation has a sensitivity of only 5.9%; this increases to 41% when considering prior treatment for clinical signs, and 71% when a standardised calf respiratory scoring system is also implemented. TUS outperforms all of these individual assessments, either in isolation or all in combination5, and is relatively simple to perform following a short training period. Demonstrating both the morbidity of respiratory disease on a unit, and its severity, can be a useful tool in driving conversation towards both prevention and improved detection and early treatment.
More than 30 respiratory vaccines for cattle are currently listed on the National Office of Animal Health (NOAH) product database, with a wide range of pathogens, mode of administration and age of administration. Selecting a respiratory vaccine for a farm must depend on a number of farm-related factors.
The two main considerations must be the pathogen distribution and the disease epidemiological pattern on the farm – what bugs are affecting which animals and when. The absence of pathogen knowledge at a farm level may lead to an inappropriate vaccine choice, poor response to vaccination and a lack of farmer confidence in respiratory vaccines.
Samples for BRD analysis are simple to take, with a range of collection methodologies, and sample assessment widely available. This includes, but is not restricted to, postmortem samples, deep nasopharyngeal swabs, tracheal washes and bronchoalveolar lavage collection tested via culture, PCR or antibody/antigen identification.
Each option has its own strengths and limitations, which have been covered in other articles. In some cases, it may be warranted to test samples from multiple sites through different test methodologies to identify the most important pathogens to control.
Once the target pathogens have been identified, the disease pattern on the farm can be used to target vaccination, with the aim to ensure protection prior to the main age of exposure, which will likely be prior to the first disease cases, and duration until after the outbreak settles. As stated already, many more preventive measures than just vaccination are available, including improving immunity through feeding and colostrum, improving ventilation and moisture control within buildings. The role of the environment was covered previously in Vet Times by Tim Potter6.
Whether the preventive measure be vaccination, environment or immunity related, a key factor in improving BRD impacts on farm is the ability of the vet-farmer relationship to effectively influence the enactment of change. Studies have shown the accuracy of veterinary content is valued by clients. However, a number of factors have been shown to be more associated with change being enacted:
These factors act synergistically on farm – it is not enough to rely on a trusting relationship with your clients to ensure the appropriate changes are put in place, but building trust within the relationship is a key cornerstone to long-term change.
The concept of shared veterinarian-farmer understanding is a bidirectional relationship. It is not enough to ensure knowledge exchange to the farmer; it is essential to also understand the farmer’s intrinsic and extrinsic motivations to change the situation. What are the farmer’s key drivers to want to change the situation? Advice can then be tailored to fit these motivational factors.
For vets to maximise the opportunity for change to be effected, they must build a trusting relationship with the client, based on a shared understanding of motivations, good knowledge exchange regarding the disease situation and an action plan tailored to the individual farm situation.
Through appropriate veterinary attention, coupled with diagnostics and a farm-specific action plan, the BRD narrative can be focused on both prevention, and early detection with prompt, effective treatment rather than fire-brigade responsive interactions. By developing relational communication methods, the appropriate changes can be implemented on farm to help control BRD.
