Prudent Use Case Study - Beef
Bovine Viral Diarrhoea (BVD) is a virus that can result in severe economic losses on beef farms. The main symptoms of BVD include:
- reduced growth
- illness associated with immune-suppression.
Pregnancy loss is the principal loss from BVD. There are two sources of BVD infection and these include Persistently Infected (PI) animals and Transiently Infected (TI) animals. Persistently Infected (PI) animals are the main way by which BVD is spread in a herd.
A PI animal is created when the dam is infected with the virus during gestation and this usually occurs within the first 4 months of gestation. If the calf survives there is a strong chance that this calf will be a PI carrier animal. Throughout their lifetime this PI animal will continually shed this highly contagious virus through their secretions. A TI animal is usually infected by a PI animal. After becoming infected a TI animal sheds the virus for two to three weeks before developing immunity and recovering.
BVD is spread in two ways:
- through direct contact between animals
- hen the BVD virus invades the foetus of a cow during pregnancy.
A compulsory BVD eradication programme was introduced in Ireland in 2013 which requires that all calves born from January 1st 2013 onwards must be tissue tagged sampled as soon as possible after birth. Where positive or inconclusive results have been obtained for calves sampled, these should be removed promptly so as to avoid herd restrictions and receive a higher level of financial support from the DAFM. Where veterinary advice is to re-test the calf this must be done by blood sample. The DAFM will cover the costs associated with this re-test. The DAFM also provides financial support for the removal of PI calves.