Watch Dan Norris' interview here
The West of England Mayor fears the killing of an alpaca in South Gloucestershire will stop others from getting their animals tested.
Geronimo the alpaca twice tested positive for bovine tuberculosis (TB) and so the Department of Food, Environment and Rural Affairs (Defra) had ordered him to be euthanised.
Now West of England Mayor Dan Norris - who is a former environment minister Defra - has said farmers will be concerned about their livestock returning positive test results.
He said: "It’s a very serious situation because I think it really is about a very awful disease, TB, which does impact on a lot of animals in our country.
"There’s understandable concern amongst many dairy farmers and cattle farmers particularly.
"But we have really got to grasp this issue because with alpacas, and llamas, their owners have to volunteer for these tests.
"What I fear now is they won’t do that because of what’s happened and that puts all of our dairy herds at risk in my view."
Geronimo’s owner, Helen Macdonald, has always maintained the results of Geronimo's tests were false positives.
She contested the warrant for his destruction – which was set to end on September 4 – in court but her pleas for a third test for bovine TB were refused.
Mr Norris added: "I think it’s really important with a significant disease like TB that causes such havoc across the West Country and the rest of Britain that we are totally transparent.
"And that we make absolutely clear that whatever we’re doing has got the backing of the best scientific approach and the support of all the people that need to be involved.
"If alpaca owners and llama owners are not going to volunteer their animals to be tested, some of those I’m afraid will have TB and that could reach cattle and cause even more havoc.
"We’ve ended up with the worst of all worlds I’m afraid and not a very good outcome at all."
Speaking from the South Gloucestershire farm after Geronimo was taken away, Helen criticised the Government for the way it handled Geronimo's case and removal.
She described Geronimo's death as "barbaric" and claimed the Government refused to engage "in good faith" in the past week.
"I’m absolutely disgusted by this Government," she added before maintaining his positive tests had "no validity".
Defra’s chief veterinary officer, Christine Middlemiss, said: "This is a terribly sad situation and our sympathies remain with all those affected by this devastating disease.
"No one wants to have to cull infected animals if it can be avoided, but we need to follow the scientific evidence and cull animals that have tested positive for bTB to minimise spread of this insidious disease and ultimately eradicate the biggest threat to animal health in this country.
"Not only is this essential to protect the livelihoods of our farming industry and rural communities, but it is also necessary avoid more TB cases in humans."