Increased Pneumonia Risk From BVD Eradication?
UK - A short term downside to the promising early progress in Scottish BVD eradication is increased risk of pneumonia in spring-born suckled calves this autumn, according to Scottish Agricultural College beef specialist Dr Basil Lowman.
11 July 2011
2 minute read
He sees the threat arising from mixing healthy cattle that are nevertheless vulnerable to BVD with others of different or unknown health status, then moving to new housing following the autumn sales.
The same risk applies, he adds, when different groups under the same ownership are combined for the winter.
“Most at risk are unvaccinated BVD-free cattle—often called BVD-naïve—that come into contact with one or more unidentified Persistently Infected individuals, which are continually producing virus and increasing infection pressure on BVD-naïve animals,” he says. “Infection of at-risk cattle with BVD virus causes weakening of their immune system and can be followed by pneumonia. This may be life-threatening in some cases, detrimental to life-long performance in many others, and will certainly increase the local respiratory virus load faced by other cattle in the same housing.”
Moreover, regardless of health status, Dr Lowman points out that sale or movement involves a number of stress factors including weaning, mixing with other cattle, transport, and acclimatisation to new housing and its pathogens, which combine to increase the threat of post-movement respiratory disease.
To minimise this risk, Pfizer vet William Sherrard advises that vulnerable cattle need protecting from BVD in advance of either movement from seller to buyer, or the mixing at housing of different groups for the same owner. “By vaccinating spring born suckler calves before sale against BVD and the three main pneumonia viruses, RSV, PI3 and IBR, sellers can help protect cattle for their buyers from post-purchase respiratory disease, at the same time maintaining a reputation for offering suckled calves with sound health status.”
Such vaccination can be done by private arrangement between buyer and seller, or it can be certified and declared publicly under the SureCalf programme, now in its fifth year (www.surecalf.co.uk). Last year, more than 3,000 SureCalf certified suckler calves were sold through autumn sales at marts in Scotland and northern England.
As Scottish eradication proceeds and more suckler herds become BVD-free, Mr Sherrard suggests that the proportion of BVD-naïve cattle at autumn suckler sales will increase, while the risk of contact with PI animals remains, albeit in decline. “So during the transition to national BVD-free status, the risk of pneumonia triggered by autumn movement prevails,” he says.
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