Screening data highlights need for bovine respiratory strategy
Bovine coronavirus could play an early role in the disease process.
Screening data has indicated that bovine coronavirus protection could be key for preventing bovine respiratory disease (BRD) in calves.
The data, collected through MSD Animal Health’s BRD screening service, suggested that coronavirus-positive cattle were significantly more likely to show evidence of other respiratory pathogens.
Researchers analysed the data from 1,732 calves that had been screened through the service between 2022 and 2026. Of these calves, 69.5 per cent had antibodies to bovine coronavirus.
Those testing positive for coronavirus also proved more likely to show evidence of other respiratory pathogens, particularly bovine parainfluenza virus type 3 (PI3) and Mannheimia haemolytica. Each additional PI3-positive calf was linked with a 37 per cent increased chance of a group being coronavirus positive.
Researchers suggest that bovine coronavirus may play an early role in the disease process.
MSD Animal Health says that the disease could be affecting the protective lining of the respiratory tract. This might be making it easier for other pathogens to contribute to disease.
Dr Kat Baxter-Smith, veterinary advisor at MSD Animal Health, said: “Seeing evidence of multiple pathogens within the same groups reinforces that BRD is rarely caused by a single pathogen. It highlights the need for farmers to take a proactive, whole-farm approach to respiratory disease prevention.”
However, Dr Baxter-Smith warns that the absence of obvious respiratory signs does not necessarily mean calves are healthy. While clinical BRD affects 11-16 per cent of calves, subclinical disease may affect 23-67 per cent of calves.
Even a small lung lesion can affect performance, since calves with 1-2cm lesions have average daily gains which are 96-138g lower than calves without lesions.
Dr Baxter-Smith added: “This is why understanding which pathogens are circulating and identifying risk factors on farm is so important,
“Vaccination, alongside good colostrum management, nutrition, housing, ventilation and hygiene, can all contribute to reducing the risk of respiratory disease.”
MSD Animal Health recommends screening to identify pathogen exposure and gaps in protection, with thoracic ultrasound used to identify lung damage and subclinical disease.
It also recommends vaccination as part of a wider prevention strategy.
“Vaccination is not a silver bullet for respiratory disease, but it is an important part of a wider prevention strategy,” says Dr Baxter-Smith.
“BRD results from a combination of infectious challenge and other risk factors, so prevention needs to focus on both reducing exposure and supporting the calf’s ability to withstand disease.”
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