Equine Viral Arteritis (EVA) Vaccines and Health Testing Protocols for the 2025 Breeding Season

As Zoetis has recently advised that Equip Artervac is unlikely to be available again before June 2025 and an import licence for the live vaccine, Arvac is unlikely to be granted by the Veterinary Medicines Directorate (VMD) in time to be administered to stallions prior to the 2025 Northern Hemisphere breeding season, it has been necessary to review and update the NSFA Breeding Regulations to ensure additional blood testing of mares continues throughout the forthcoming season (https://nsfa.org.uk/information/). 

As per last year, mares who have not been outside of the UK and Ireland within the last 12 months will need an EVA taking as soon as possible after 1st January, as well as within 30 days of covering.  The TBA would encourage breeders to have dialogue with their respective stallion studs at the earliest possible opportunity, if they wish to a) cover fillies in training or b) make decisions later in the season to cover mares who did not have an EVA blood test taken routinely in January 2025, to understand the specific requirements for these horses, which are at the discretion of each stud.

The TBA has consulted broadly across the British thoroughbred breeding community in the formation of this protocol and whilst it was recognised that an additional blood test(s) does equate to increased costs, it was considered important to monitor the population in case of disease outbreak, which could create huge equine health and financial implications for the sector.    

Some previously vaccinated, lapsed stallions may still be seropositive but will have reduced immunity, whilst British-based first and second-season stallions will not have been vaccinated to date, meaning they are vulnerable to infection.  EVA is a notifiable disease, which is often subclinical.  Equine Infectious Disease Surveillance (EIDS) has produced guidance and a decision tree for stallion managers (https://equinesurveillance.org/landing/resources/eids2025ActionWithoutArtervac.pdf), to ensure they are compliant with the requirements of Defra’s Animal Disease Policy Group in implementing the EVA Order (1995).

The health and welfare of the British thoroughbred population are of paramount importance to breeders and the TBA is grateful to all participants for taking these necessary extra biosecurity measures to safeguard the industry’s EVA disease-free status, which is critical in facilitating further improvements in the policy and process for moving High Health status thoroughbreds across the borders.

If you have any questions, please call the TBA office on 01638 661 321.