A total of 100 horses and ponies have been enrolled for this pilot study.
This pilot study is in preparation for a full vaccine trial, which is likely to commence in 2013-2014 subject to securing sufficient funding, which will involve at least 1000 horses and ponies.
Dr Jo Ireland of the Animal Health Trust, who is piloting the vaccine trial said: "This is very exciting news and we are working flat out to get the study up and running. There is still a lot of work to do before launching the full nationwide vaccine trial, and this initial study will help us to ensure that the trial design will be practical to perform on a larger scale."
The Equine Grass Sickness Fund is spearheading a campaign to raise funds for the full vaccine trial, which is being run in collaboration with the Animal Health Trust, The (Dick) Vet and Liverpool University's School of Veterinary Studies.
Kate Thomson, spokesperson for the Fund, said: "We are over the moon that the vaccine trial is finally here, but fundraising now starts in earnest to ensure that the full trial can go ahead. Grass sickness takes a devastating annual death toll, and we are appealing to every horse owner in the UK to help bring an end to the disease by donating to this cause."