Under tough new rules that come into force on March 1, 2026, breeding females from Northern Ireland herds with BVD-positive animals will be prohibited from being sold or given away for up to 41 weeks.
The Department of Agriculture, Environment and Rural Affairs (DAERA) said the restrictions apply to all females over 12 months old in the affected herds.
The move directly targets the risk posed by so-called “Trojan horse” animals – pregnant cows that are exposed to bovine viral diarrhea (BVD) during pregnancy and whose calves can be born with persistent infection.
In practice, this means that heifers calving in the spring in a restricted herd may not be allowed to move off-farm until calving is complete and the calf tests negative.
This regulation forms part of the phased implementation of the BVD Regulation Order (NI) 2024 and marks the next stage of eradication efforts. Northern Ireland has been working to eliminate BVD for more than a decade and levels of the disease have fallen significantly in recent years.
DAERA Minister Andrew Muir said: “The introduction of the ‘Trojan Horse’ regulations marks another important step in eliminating BVD from Northern Ireland.”
He said the movement of pregnant females carrying infected calves “is one of the hidden sources of disease spread and one of the most difficult to control,” adding: “These new rules directly target that risk.”
Mr Muir said farmers were already making great progress. “Farmers across Northern Ireland are working hard to reduce disease levels and these additional controls will help protect that progress,” he said.
He urged cattle keepers to work closely with veterinarians, maintain timely inspections and understand veterinarians’ responsibilities. “These new requirements will allow cattle farmers to protect their herds, support their neighbors and completely eliminate this disease from their cattle populations.”
Under this measure, breeding females from a herd with a confirmed BVD-positive animal will be restricted from moving off-farm for up to 41 weeks after the last infected animal is removed.
Restrictions will remain in place until the female gives birth and the calf tests negative for BVD. They may be lifted sooner if certain blood test conditions are met, such as evidence of previous immunity or a clear antibody result taken at least 21 days after the removal of the last positive animal.
BVD-tested animals will continue to be allowed to be directly slaughtered, disposed of as animal by-products, or moved under a Ministry permit in exceptional cases.
The ‘Trojan Horse’ restrictions follow stricter herd-level measures introduced on 1 February 2026, with herds being immediately restricted if a BVD result is positive or inconclusive. Controls for individual women were originally scheduled to begin on the same day but were postponed to allow updates to the NIFAIS database.
BVD is primarily spread by persistently infected (PI) cows, who acquire the virus in utero and shed it throughout their lives. Animals that are temporarily infected can also spread the infection for a short period of time until they recover.
For producers trading seed stock, especially calves and heifers, the new rules could have a significant impact on marketing and cash flow if infections are detected.
However, the ministry argues that eradication is now firmly within reach and stricter controls on high-risk animals are essential to complete the job.
Further guidance on how this measure will be implemented is available on the DAERA website.
