The single biggest improvement in animal health that I have witnessed since I qualified has been the introduction of a vaccine against BVD. Prior to this we had clients who simply could not rear healthy calves. The circulating BVD virus caused widespread immune suppression and resulting calf diarrhoea, pneumonia, ill thrift and high mortality. National compliance has been good with almost 100% of calves being tested. However, worryingly, it has been reported recently that up to 30% of persistently infected calves that have been identified are still on farms. Each one of these P.I’s is a ticking time bomb, not only for that farmer, but also his neighbours.

Calves are born Persistently Infected (P.I) with BVD virus following in-utero infection of its mother between months two and four of pregnancy. The majority of these cases (94%) are due to the pregnant animal being infected for the first time with BVD virus.

The majority of P.I’s do not thrive and die from scour or pneumonia within 12 to 18 months. They are a massive reservoir of the virus which they spread by direct or indirect means. All bodily secretions e.g. faeces, urine, etc. carry millions of virus. The idea of isolating a P.I on a farm is impossible with the level of contagion that they pose. More worryingly, I have heard it suggested that owners might move them to a quiet outside farm. Imagine the unsuspecting neighbours bordering this land, with BVD virus emanating from all orifices. Most P.I’s die before they get to a salvageable weight and it makes no sense to keep them.

It is Animal Health Irelands’ intention that the testing phase of BVD eradication will progress into a monitoring phase. Two of the criteria to enter this phase are:

  • BVD test status of all animals must be known
  • Having no animals with persistent or transient infection with BVD virus in the herd for 12 months prior to entering the monitoring phase. Any P.I animal on farms will have to be disposed of by the end of 2013 in order to enter the monitoring phase in January 2015.

    • We have come a long way, through vaccination and now eradication, in battling BVD It would be a pity if we didn’t seal the deal by eliminating these P.I’s. Keep your bio security levels high and continue vaccinating.

    *Brian Ryan works at Mulcair Vet Clinic, Cappamore, Co Limerick. Mulcair Vet Clinic is part of XLVets. XLVets is a group of progressive practices who are working together to achieve a better future for agriculture and veterinary in Ireland. For further information go to www.xlvets.ie