National Veterinary Services (NVS) has published new guidelines for veterinary surgeries ordering the bluetongue vaccine Bovilis BTV8.
The company notes orders will only be processed if they are received on its faxback order form by 15:00 BST, with no telephone or electronic orders accepted.
Furthermore, the vaccine will only be supplied to practices within the protection zone defined by the Department for Environment, Food and Rural Affairs.
"All orders must be signed by a veterinary surgeon," NVS said. "Orders received without a veterinary surgeon signature will not be processed."
It adds it will accept advance vaccine orders for animals outside the protection zone which may be included at a later date, with the vaccine only supplied to those animals that are inside at the time of ordering.
Last week, Defra announced an extension of the protection zone to include the counties of Durham and Tyne and Wear.