About Bovine Viral Diarrhoea (BVD)

BVD is spread by carriers, known as persistently infected (PI) animals. Getting rid of PI animals is the only way to get rid of BVD from your herd.

PI animals are born with the virus in their body, either because their mother is also a PI animal, or because she was exposed to the virus in the first four months of pregnancy.

These infected animals don’t grow well and 50% die by the age of two. Some survive longer and can spread the infection for many years.

Cows that are infected with BVD in the first four months of pregnancy are more likely to miscarry or have a stillbirth and also produce PI calves.

PI animals can also infect cows later in pregnancy and cows that aren’t pregnant, though the consequences are less serious. The animals usually recover, but while they are unwell they produce less milk and they can have other problems such as:

• weight loss
• lower conception rates
• increased susceptibility to diseases such as mastitis.