BVD Vaccination Reminder

Preparing breeding bulls for mating in Spring

Blood testing for PI BVD animals
For the past 15 years, bulls used in dairy or beef herds have been screened for “PI” BVD status. PI refers to “persistently infected”.
PI bulls are those bulls infected with BVD inside their mother during pregnancy. They remain infected, are carriers of BVD virus and are capable of infecting other cattle for their entire life.

Overall, PI bulls (like PI cows) have a vastly reduced life expectancy, often exhibit poor health and are likely to have reduced fertility. Importantly, they shed BVD virus and infect other cattle.
The virus shed during mating can have a huge impact on cow health, reduce conception rates and lead to early embryonic death, late returns, abortion and infertility.

Bulls that have not been properly vaccinated for BVD and arrive at the property for the purposes of getting cows pregnant, are themselves put at high risk of contracting BVD infection and being rendered sub-fertile or even completely infertile.

When the breeding bulls do not do the job for which they were purchased, buyers and sellers are dissatisfied and repeat business is unlikely. BVD infection of breeding bulls is a potential cause of this breeding failure and is preventable through blood testing and vaccination.

Bulls need to be vaccinated twice, three to four weeks apart, with the last vaccine given at least 10 days prior to arriving on farm. Although bulls are usually only retained for one season in dairy herds, vaccination of bulls along with blood testing for BVD is a must. The financial investment is small, but often it is the inconvenience of having “another thing to do” which means it is not done.

However, the logic behind vaccinating for BVD is real and simple. Bull breeders need to organise blood testing and vaccination to ensure any bull infertility through BVD is eliminated.

Bull buyers need to insist that as part of the deal, bulls are fully vaccinated as well as blood tested for PI status. As mentioned, the key is that both testing and vaccination are essential, one or the other alone is not enough.