Farmers who experience an outbreak of BVD should stop moving livestock out of their herd for at least three weeks, the body that runs the BVD eradication programme in NI has advised.
Animal Health and Welfare NI (AHWNI) said cattle that are infected with BVD for a short period, known as transiently infected animals, can still pass on the BVD virus to other cattle.
The industry group said there have been BVD outbreaks in NI where the only apparent explanation was the purchase of cattle that had negative BVD test results at birth.
The negative test at birth means the cattle were not persistently infected (PI) with BVD, so they must have been transiently infected for a short period. If a cow picks up BVD during the first half of pregnancy, then her calf will be a PI when it is born.
The latest figures show that 128 out of the 148 BVD positive cattle that were disclosed in January were culled within five weeks.
It is understood that plans are being progressed within DAERA for compulsory movement restrictions to be imposed on herds that retain PI calves.