Understanding BVD's devastating welfare impacts and the national eradication programmes to address them.
BVD causes multi-faceted welfare impairment across affected herds. Primary infection in naive pregnant cows causes embryonic death, abortion, congenital defects, and birth of persistently infected (PI) calves. Each outcome represents welfare loss — for the cow experiencing pregnancy failure, and for congenitally affected or PI calves born with compromised immune function.
PI cattle experience a particularly grim welfare trajectory. Immunotolerant to BVD, they are unable to mount an immune response to the virus they carry. Most PI animals eventually develop mucosal disease — a devastating condition causing oral ulceration, profuse haemorrhagic diarrhoea, and death within weeks of onset. The suffering of mucosal disease is severe and inevitable for all PI cattle that survive beyond the first year.
The immunosuppressive effect of BVDV infection compounds welfare harms across the herd — increasing susceptibility to respiratory disease, bovine respiratory disease complex, and other infections. Eradication through PI identification and rapid removal is the most impactful welfare intervention available.