Caution urged when dealing with BVD viral infection 04/08/2020

Caution urged when dealing with BVD viral infection

The incidence of BVD in NI is higher than industry would wish at this stage of the eradication programme.  Recent data suggests a slowing in the rate of progress for the programme.  For example, the monthly BVD prevalence for May 2020 is slightly higher than the monthly BVD prevalence seen in May 2019. 

There are several factors relating to BVD positive animals that are impeding progress.  While the number of retained positive cattle continues to reduce each month (August figures indicate that retained PI numbers have fallen by almost 40% to 170 animals in 117 herds since the implementation in June of the new BVD standard in the FQAS), there is evidence of a number of emerging cases of BVD and the likelihood of hotspot areas existing.

Farmers with BVD viral infection in their herds are asked to deal with BVD Positive cattle with extreme caution, to minimise the risk of infected material being transferred within their farms or to other farms.  Strict isolation of cattle that have returned positive or inconclusive results is critical.  An animal with a BVD positive or inconclusive result may be retested (using a blood sample taken by a private vet) and any Persistently Infected (PI) animals should be culled at the earliest opportunity. 

The outcome for farmers who have retained PIs is often very serious in the following calving season.  Some large outbreaks have occurred lately in suckler herds where positive calves were not culled in a timely manner last year and were left running with the cows, thus allowing the infection of pregnant dams at a critical stage, leading to further PI births.

BVD positive or inconclusive animals are restricted to their herd.  Any movements of BVD positive animals to other herds could be contributing to the spread of the virus and to unexplained outbreaks.  PI cattle that have moved in the NI cattle population will be silent spreaders of the BVD virus.  The risk is to their current herd, neighbouring herds and possibly to multiple other herds through the movement of transiently infected animals, pregnant females carrying PI calves, and contaminated material.  Any movement of BVD positive cattle is therefore an obstacle to eradication. 

The BVD Implementation Group has requested that, after a reasonable amount of time has been given to farmers to allow retesting of PI animals, herd restrictions are applied by DAERA, in order to encourage prompt culling of PIs and reduce the risk of onward transmission of the virus.