Downward trend in number of living BVD Positive cattle 11/05/2020

Downward trend in number of living BVD Positive cattle

Current figures for the BVD Programme show encouraging signs that the number of BVD Positive animals being disclosed in affected herds is on a downward trend.  In the last two months, the number of living BVD Positive cattle has fallen to below 400, the lowest number seen in the Eradication Programme to date.  Overall, the scheme has resulted in herd level prevalence falling by over 50% since the end of the first year of the compulsory programme.

The number of living BVD Positives noted in affected herds has halved in the last 12 months and the numerical profile of living infected animals per herd has improved, with only 3 herds in NI having more than 4 BVD Positives at the start of May 2020 compared to 17 herds with more than 4 BVD Positives in May 2019.

However, every single occurrence of BVD is critical.  The number of herds with single living BVD Positives has fallen from 307 herds one year ago to 188 herds this month.  An initial Positive or Inconclusive test result for BVD virus in a herd suggests that cattle in that herd have been exposed to the BVD virus, therefore the virus could still be present in other stock or there could be another source of BVD virus that could continue to put the herd at risk, through further transmission to susceptible animals (particularly breeding stock).

Timely testing is of paramount importance, as the prompt identification and removal of PI cattle is the key to disease control.  In the current pandemic situation, farmers are strongly encouraged to take ear tissue samples promptly after birth (as soon as the calf is dry).  Early sampling of calves reduces the possibility of inadvertently detecting transiently infected calves that have acquired infection after birth.  If tissue samples are stored in a fridge before dispatch to a laboratory, they should be kept for no longer than 7 days.  (Herd owners should be aware of possible postal delays due to Covid-19.)  Untested animals may not be moved from a holding until they are sampled and a negative test result for that sample obtained from an approved laboratory.

While the progress made in reducing the prevalence of BVD is welcome, it is vital that PI calves are culled so that this highly infectious virus can ultimately be stamped out.  A relatively small number of farmers have not been testing their calves on time or disposing of calves that are Persistently Infected with BVD, leaving the virus circulating on NI farms.  The benefits of eradicating BVD from herds are well known but bear repeating: they include decreased costs of production (through reduced costs in tackling the disease and fewer losses), a reduced need for the use of anti-microbials, increased resilience to other diseases and improved cattle welfare.