Bovine Viral Diarrhoea (BVD) virus is one of the most important viral infections of cattle. The virus infects cattle of all age groups, including the unborn calf.
BVD can cause devastating losses in individual herds.
The cost: £40–60m to the national herd in health and productivity loss (Bennett R. 2005).
Three vaccines for BVD virus (BVDV) were marketed in the UK:
- Bovilis BVD contains inactivated BVDV
- Bovidec contains inactivated BVDV
- Bovela contains modified live BVDV
AssumptionsNumerator: The number of doses of vaccine administered has been calculated by multiplying the number of packs sold by the number of doses per pack.
Denominator: Common industry practice is to give breeding heifers a primary course of vaccination before first service, (between one and two years) and all breeding females over two years of age an annual booster. It was assumed that only female breeding animals should be vaccinated and that the at-risk population was all female cattle over one year of age.
The primary vaccination course for vaccines containing inactivated BVDV is two doses of vaccine separated by a three- or four-week interval. For these products, when calculating the denominator, the number of cattle between one and two years of age were, therefore, multiplied by two to take this into account, which was then added to the number of female cattle over two years of age. The primary vaccination course for the vaccine containing modified live BVDV is one dose of vaccine, and so the denominator was all female cattle over one year of age.