Vets who qualified in the Republic of Ireland will be able to keep practising in the UK in event of a no-deal Brexit.
The deal, which was reached by UK and Ireland's veterinary regulators, is particularly important for NI as many of its vets qualified in Dublin.
University College Dublin has the only school of veterinary medicine on the island of Ireland.
It will also mean UK-qualified vets will be able to continue practising in Ireland.
Dr Niall Connell, president of the Royal College of Veterinary Surgeons, said: "We are glad to be able to sign this agreement with the Veterinary Council of Ireland which is a vital element of future-proofing."
Currently, EU citizens who graduate from University College Dublin (UCD) have an automatic right to work in the UK via the EU's mutual recognition of professional qualifications directive.
The new agreement means, whatever the Brexit outcome, UCD graduates can join the register of veterinary surgeons in the UK, and UK graduates can join the equivalent register in Ireland.
"The veterinary profession in Great Britain and throughout the island of Ireland has moved step-by-step and shoulder-to-shoulder in unison over the years and recent political events will not sever that important bond," said Peadar Ó Scanaill, president of the Veterinary Council of Ireland.
"Co-operation and mutual recognition are the key components of our future together."