Guidance for Mare Owners
After the recent batch of Equip Artervac (Zoetis) failed post-production clearance testing, the absence in availability of this vaccine, which helps protect stallions and the industry against Equine Viral Arteritis (EVA), will mean that stallion immunity will be reduced this year. EVA is a notifiable (in England, Scotland and Wales), viral disease, which is often subclinical and transmitted by close contact, or venereally and is endemic on the continent. Importation of an alternative, live, American vaccine, Arvac is being explored by managers and Defra, but will not be available in time for this breeding season. Most previously vaccinated stallions were correctly blood tested following their last vaccination (with samples stored at Rossdales Laboratories for paired testing), and therefore should comply with Defra regulations (EVA Order 1995).
Following discussions and meetings in December, stallion stud managers agreed that retaining routine post January 1st swabbing and blood testing is important for annual biosecurity screening, but an additional EVA blood test from mares would be needed no more than 30 days before they are covered. If this test is taken close to the covering date, it may also be acceptable for a covering in the subsequent oestrus period if she fails to conceive to the first service (assuming the mare is returning to the same stallion). If the mating is due to take place on a date within 30 days of the routine January screening, a second blood test will still be required (i.e. a minimum of two blood EVA tests will be necessary). As always, mare owners are advised to consult with the stallion stud prior to every covering, to check their specific requirements.
Biosecurity and welfare of the thoroughbred breeding population are paramount and the recommendations within the HBLB International Codes of Practice should be followed at all times. Of particular importance in the context of EVA, are close adherence with quarantine protocols for imported mares and the separation of thoroughbred and non-thoroughbred horses on stud farms.