Dr David Graham, Animal Health Ireland

Bovine Viral Diarrhoea Virus (BVDV) is recognised to be one of the most economically important viral diseases of cattle in Ireland. Available evidence highlights the prevalence of exposure to BVD virus in Irish herds. In the dairy sector, independent surveys based on bulk tank milk and blood sampling, show evidence of exposure in essentially all herds. A recent blood-based survey in the suckler sector found similarly high levels of exposure. These results do not necessarily mean that all of these herds currently contain one or more PI animals, but they do indicate that most, if not all herds have recently been exposed to BVD virus.
Using different approaches, a number of European countries have already completed or are currently engaged in national or regional BVDV eradication programmes. To explore the views of industry on the feasibility of this type of co-ordinated national BVDV eradication programme in Ireland, AHI recently completed a consultation process to gather their views. This was accompanied by extensive consultation with stakeholders and revealed a significant degree of support for such a programme. There was also strong feedback that such a programme should be conducted intensively with as short a timescale as possible and be based around the testing of ear punch samples collected as part of the official identity tagging process. DAFF is currently tendering for the supply of such tissue test tags for use in 2012.
While the high level of infection in Irish herds is recognised, the consultation process highlighted a lack of information on the annual economic losses due to BVD virus in the Irish cattle industry. To address this knowledge gap, AHI recently commissioned the Scottish Agricultural Colleges (SAC) to undertake a modelling study to estimate these losses. This study took data on the Irish national herd and combined it with recent commodity costs drawn mainly from CSO and the national farm accountancy survey (NFAS) and combined it with models describing the spread and impact of BVD virus infection in dairy, suckler and finishing herds to produce annual costs for disease in each of these three sectors. The study estimated annual losses totalling at least €102m, consisting of €55m, €27m and €20m in the dairy suckler and finishing sectors respectively. At the animal level this is equivalent to
€48/year for every dairy cow and €30/year for every suckler cow. These figures show clearly the significant losses suffered by Irish producers due to BVD virus.
Following on from the consultation exercise a BVD Implementation Group consisting of representatives drawn from across industry are now meeting to plan the implementation and delivery of a co-ordinated industry-led national BVDV eradication programme. It is anticipated that this programme will be voluntary in 2012, leading to a national compulsory programme in 2013. The SAC study has also modelled the costs of the anticipated eradication programme to determine the economic viability of the proposed approach. Based on the consultation responses, this programme is envisaged to consist of three years of tissue tag testing of calves followed by a further three years of surveillance based around bulk milk tank testing or targeted blood sampling. Herds with negative tissue tag test results would require minimal further sampling at the end of the three year intensive sampling period whereas herds with positive tests during this period (estimated to be 25% of herds) would require additional testing to identify and remove any further PI cattle. Costing of such a programme inevitably involves a number of assumptions. These have been made on as conservative a basis as possible to avoid under estimation of costs. Calculations show the estimated total cost for the six year eradication programme to be €49m with €21m and €28m attributed to the dairy and suckler sectors respectively.
Based on these figures, it is estimated that the annual losses due to BVD infection during the six-year programme exceed the annual eradication costs by a factor of at least 10. The benefit:cost ratio in the dairy sector was at least 14:1 while in the suckler sector it was at least 5:1. When analysed in terms of pay back period it was found that the total costs of the programme in the suckler sector would be recouped by saving just over one year’s losses, while the costs in the dairy sector would be recouped in around six months.
As already mentioned, these figures are based on a number of assumptions. Nonetheless, they clearly show both the significant year on year losses due to BVD virus in the national herd and the significant net benefit associated with the proposed short-term, intensive, eradication programme. Successful delivery of this programme will require all sectors of the industry to work together with the common goal of eradication.
However, for the voluntary period of 2012 a critical step for participation will be ordering of the appropriate tissue sample enabled tags for use next year. As already mentioned, these should be available for ordering from November onwards this year.