The latest maps of Bovine Viral Diarrhoea (BVD) infection in NI to be produced illustrate a marked decrease in the level of disease being detected compared to the previous maps that were produced almost one year ago. 

An important indicator of the progress of the industry-driven BVD Eradication Scheme is the decline in the number of Persistently Infected (PI) calves being born: Map 1 demonstrates that the scale of PI births has dropped significantly in most parts of NI. 

While the herd level prevalence of BVD has more than halved since the end of the first year of the compulsory programme, at the start of December 2019 there were 416 PIs alive that had been retained on farm for more than 5 weeks, in 285 herds.  The number of retained PI animals is a cause for concern, as each BVD positive animal poses an ongoing risk to other cattle in its herd and on neighbouring farms.  As a result, the disease may be perpetuated, through the infection of early in-calf cows and heifers.  This may result in a new crop of PI calves being born during the following calving season and so the virus will continue to circulate.  

Map 2 identifies general locations where PIs are still alive.  In some cases, the higher densities of PIs are due the fact that some farms have had multiple PIs disclosed on testing.  The location of retained PIs (those PIs that are still alive on farm more than 35 days after the positive result was disclosed) may be seen on Map 3, demonstrating the risks that exist for other herd keepers. 

AHWNI chief executive Dr Sam Strain commented on the latest BVD maps, saying, “These maps provide a useful summary of the current BVD situation as well as highlighting the areas of greatest risk to herd owners.  While very good progress has been made leading to undoubted savings for farmers, failure of some farmers to cull PIs is slowing the scheme’s progress.  Veterinary advice is that farmers should dispose of BVD PIs at the earliest opportunity, so that BVD can ultimately be eliminated from the NI cattle population.”

Overall, the maps show the all-island picture of BVD infection and allow comparison of the progress being made in tackling the disease.

Map 1: PI Births 

Map 2: Map showing distribution of PI's still alive

Map 3: Map showing distribution of retained Persistently Infected (PI) cattle 

Note for editors:

1.      The BVD maps, which use anonymised data and fixed sized hexagonal units to represent disease densities, are produced by the Centre for Veterinary Epidemiology and Risk Analysis (CVERA), University College Dublin, and are the outcome of a collaboration between Animal Health Ireland (AHI), Animal Health and Welfare NI (AHWNI) and DAERA.  They are based on statistics covering up to the start of December 2019. 

2.      For any queries, please contact AHWNI at info@animalhealthni.com / 028 7963 9333.