Around 50% of calves born after 1 March 2016 and positively identified as being persistently infected (PI) with bovine viral diarrhoea (BVD) are still being retained on farm, according to figures from Animal Health and Welfare NI (AHWNI).

At the end of 2015, the then Agriculture Minister Michelle O’Neill announced that BVD testing would be made compulsory for all calves born on or after 1 March 2016.