Christmas meat supplies are facing serious disruption after abattoir vets threatened strike action.

Vets working for Grants Veterinary Services, which supplies about a quarter of the vets to the Meat Hygiene Service, are currently balloting to strike over pay, contracts and union recognition. A decision on the ballot is due on November 20, and Unison warns any stoppages would hit the crucial Christmas meat supply period.

"The vets in abattoirs make sure animals are treated humanely, and that the famous English roast is safe to eat," said Unison regional organiser Chris Jenkinson. "But they are threatening to hang up their aprons unless their employers recognise Unison and stop plans to cut pay, terms and conditions and impose a new employment contract."

It is not the first time the union has threatened to disrupt Christmas. Unison planned a walkout of meat hygiene inspectors in November last year but called off the strike late in the day after a deal was reached.

An MHS spokeswoman played down fears of Christmas shortages, insisting the service had contingency plans and would be able to cover for striking staff. "Grants Veterinary Services is working with the MHS and keeping us fully informed on developments and how they plan to continue the service they provide to us," she said.

Meanwhile, it has emerged that new poultry marketing standards could mean a shortage of turkey next Christmas. EU ministers last month updated rules, meaning from May 2010 poultry can no longer be labelled fresh or chilled if it has been frozen before.

With some retailers selling Brazilian turkey that has been frozen and thawed, new supply arrangements will have to be made. "It will cause problems to the Christmas turkey sector, but it's good news for British farmers and we think it's important that when you buy something fresh it has not previously been frozen," said NFU poultry chairman Charles Bourns.