BVD is a viral disease of cattle caused by BVD virus. Infection can result in a wide range of clinical signs including:
- Reproductive problems, including failure to conceive, abortion and birth defects.
- Calves that survive infection during early pregnancy are born persistently infected (PI) with the virus.
- PI cattle may develop a fatal condition called mucosal disease.
- Most PI cattle die before 2 years of age- either from mucosal disease or other illnesses.
- Weakening of the immune system, leaving cattle more susceptible to other infections, particularly scours and pneumonia in calves.
The programme is supported by legislation. Key points include:
- Requirement to test all calves born from 1st January 2013 onwards. In May 2020, legislation was amended to provide for the compulsory BVD testing of all cattle, including those born before the 1st of January 2013. This excludes female animals that have not had one or more calves which tested negative to BVD.
- Ban on sale of calves without a negative result.
- Follow up testing where PIs (persistently infected animals) are identified.
How is it spread?
Calves become persistently infected (PI) when their mother is exposed to the virus during the second to fourth month of pregnancy (or if the mother is PI). PI cattle are the main source of infection within herds and means of spread between herds.
How can it be eradicated?
The key is to identify and remove PI cattle from the national herd. This can be done cost-effectively by testing ear punch samples collected by you as part of the official identity tagging process.
How does the compulsory programme work?
All the official tissue tags for use since 2013 include one which is specially adapted to collect a tissue punch during the tagging process. Samples must be sent to any one of the several laboratories designated for this purpose to be tested for the presence of BVD virus. Further testing will be required in herds with positive calves. Results will be issued by ICBF using SMS (text) messages and letters.
What happens to PI calves?
While apparently normal at birth, PI calves often become ill-thrifty and die before reaching slaughter weight. During this time they remain a source of infection for other cattle, which may lead to the birth of further PI calves. It is recommended that PI cattle are isolated and culled as soon as possible after being identified.
Animal Health Ireland launched a stakeholder consultation to gather the views of all aspects of the industry on the level of support for a co-ordinated industry-led national programme to eradicate BVD in Ireland during November 2010. This ran for three months and was accompanied by extensive stakeholder consultation.
Overall there was strong support for such a programme, with a preference for the testing of tissue tag samples (taken as part of the official identity tagging process) as the primary diagnostic method.
The absence of specific data relating to the losses due to BVD in Ireland, and the costs of a tag-based eradication programme were identified as critical knowledge gaps. To address this AHI commissioned SAC (Scottish Agricultural College), who have extensive experience in this area, to do the work reported here with two objectives; estimating the benefits of freedom from BVD to the Irish beef and dairy sectors at farm level, and estimating the costs of eradicating BVD from Ireland.
- Annual losses due to BVD in the Irish cattle industry were estimated to be 102M euro.
- The total cost to industry of a six year eradication programme was estimated to be 54M euro.
- The overall benefit:cost ratio for eradication was estimated to be 10:1 i.e. a return of ten euro for each euro spent during the six years of the programme.