Published: 05 Mar 2025 | Last Updated: 05 Mar 2025 15:46:57

New research from the Royal Veterinary College (RVC), combining thoracic ultrasound alongside the measurement of clinical signs, has revealed that nearly a third of calves in the UK experience bovine respiratory disease and subclinical pneumonia. These findings will support veterinary professionals in identifying the optimal techniques to use to precisely diagnose the condition, supporting bovine welfare.

Approximately 1.4 million dairy calves are born in the UK each year, yet bovine respiratory disease is one of the leading causes of disease in pre-weaned calves and is the main reason for antibiotic use in this population. However, diagnosis of the condition is challenging and has traditionally involved the assessment of clinical signs using scoring methods such as the Wisconsin Respiratory Score, which identifies disease based on visible signs including cough, nasal or ocular discharge, ear position and temperature. However, more precise techniques for the diagnosis of disease are available, such as thoracic ultrasound, which can help to diagnose the condition with greater precision.

The research team, led by George Lindley, European Veterinary Specialist in Bovine Health Management and PhD student at the RVC, sought to combine both techniques to measure disease levels in UK dairy herds. This is the first study of its kind to explore the frequency of bovine respiratory disease using thoracic ultrasound in a large subset of English dairy herds.

Researchers measured the occurrence of bovine respiratory disease in 476 calves born on 16 dairy farms located in south-west England. Researchers performed a total of 3,344 weekly exams from birth until weaning (approximately 8 weeks of age), measuring the respiratory health of calves using both ultrasound and scoring techniques.

The research revealed that the peak prevalence of lung consolidation, where air in the lungs is replaced by a solid, fluid or other material, occurred at 8 weeks of age, reaching 29%. The research also found that subclinical pneumonia, the presence of lung consolidation without outward clinical signs, was common. At any week of age, up to 28.7% of calves were diagnosed with subclinical pneumonia.

These findings demonstrate that subclinical pneumonia was common in our UK population of dairy-born calves, but diagnosis could easily be missed if stakeholders only observed clinical signs. Clinical respiratory scoring will not identify all cases of bovine respiratory disease and thoracic ultrasound is an essential diagnostic technique which should be implemented by vets in clinical practice to support cattle welfare.

George Lindley, PhD student at the RVC and lead author, said:

“The results of this study demonstrate that bovine respiratory disease, including lung consolidation identified via thoracic ultrasound, is common in pre-weaned calves born on UK dairy farms. Whilst the disease has negative welfare consequences, affecting growth, survivability and future productivity, our research suggests that a significant proportion of calves born on UK dairy farms may remain undiagnosed when assessed by clinical signs only. Thoracic ultrasound is fast and relatively easy to perform and we hope that more widespread engagement will help to improve youngstock health and performance.”

This research was funded by the Barham Benevolent Foundation.

Notes to Editors

Reference

Lindley, G.; Blackie, N.; Wathes, D.C.; Booth, R.E. Development and Progression of Bovine Respiratory Disease Measured Using Clinical Respiratory Scoring and Thoracic Ultrasonography in Preweaned Calves on Dairy Farms in the United Kingdom: A Prospective Cohort Study. Animals 2025, 15, 360.

The full paper is available here: https://www.mdpi.com/2076-2615/15/3/360

DOI: https://doi.org/10.3390/ani15030360

RVC has extensive livestock and food systems research expertise, exploring new approaches to growing challenges of livestock production and addressing infectious disease controls. It draws upon a variety of disciplines such as epidemiologists, public health experts, economists, wildlife biologists at the herd, individual animal and molecular level and at the pathogen level (virologists, bacteriologists, parasitologists). You can read more here: https://www.rvc.ac.uk/research/integrated-research-in-livestock-and-food-systems.

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About the RVC

• The Royal Veterinary College (RVC) is the UK's largest and longest established independent veterinary school and is a Member Institution of the University of London. 
• It is one of the few veterinary schools in the world that hold accreditations from the RCVS in the UK (with associated recognition from the AVBC for Australasia, the VCI for Ireland and the SAVC for South Africa), the EAEVE in the EU, and the AVMA in the USA and Canada. 
• The RVC is ranked as the top veterinary school in the world in the QS World University Rankings by subject, 2024. 
• The RVC offers undergraduate and postgraduate programmes in veterinary medicine, veterinary nursing and biological sciences. 
• The RVC is a research-led institution, with 88% of its research rated as internationally excellent or world class in the Research Excellence Framework 2021. 
• The RVC provides animal owners and the veterinary profession with access to expert veterinary care and advice through its teaching hospitals and first opinion practices in London and Hertfordshire.