The director of a Tasmanian horse transport business has blasted authorities for not releasing information about the cause of death of 16 polo ponies that travelled on a truck across Bass Strait.

A month on from the ponies’ deaths — at some time during their journey between Devonport on the Spirit of Tasmania ferry, and a rural Victorian property — there are growing calls for details about the case to be revealed in the public interest.

Hayley Sheehan of the Latrobe-based Tasmanian Horse Transport told the ABC she had been inundated with inquiries from horse owners worried about their animals crossing Bass Strait.

Ms Sheehan said Tasmanian businesses were suffering, and the sector deserved answers.

“We’re finding some people will not sell a horse to Tasmania, and some people will not buy a horse in Tasmania, because there’s this uncertainty, this cloud hanging around as to what happened to these 16 horses,” she said.

“Who’s at fault? Why did they die? I’m quite sure by now the authorities would have a clear understanding of why they died, and I think it’s about time that the horse industry in Tasmania found out exactly what went wrong.”

The multi-agency investigation into the ponies’ deaths is being lead by Tasmania’s Department of Primary Industries (DPIPWE), and has involved veterinarians at the Charles Sturt University in Wagga Wagga in New South Wales, the Victorian Department of Agriculture, and the Australian Marine Safety Authority.

DPIPWE investigation yet to find a cause

Late on Tuesday, DPIPWE issued a statement saying that at this stage of investigations, the deaths of the horses appear to be an “isolated incident”.

It said the movement of horses across Bass Strait was considered safe, “in line with animal welfare regulations and TT Line’s conditions of carriage when transporting horses”.

DPIPWE said it had pathology reports and was continuing investigations.

“While it is apparent this was an isolated incident, no information received to date points to a clear cause of mortality, the statement said.

“Some laboratory results that normally take extra time are expected to be received soon and may or may not contribute to understanding a cause.”

The university’s vets conducted the autopsies weeks ago after the truck’s driver — high-profile national polo identity Andrew Williams — drove the dead animals to their doorstep, and the institution is not commenting.

The results now lie with DPIPWE, and Mr Williams’ legal team.

Mr Williams said at the time, discovering the dead horses was his worst nightmare.

“Within an hour of leaving the boat, I had 16 horses that were cold dead and two fighting to survive,” he said soon after the event.

“I just went into survival mode for the surviving two, and after offloading them in Yarra Glen, I was on the road with the 16 dead polo ponies to Wagga Equine Hospital.

“No-one should go through what I have recently gone through. I am just trying to stay busy, but it’s there, and I can’t see it going away until we have some answers.”

After releasing a statement to the ABC in the week after the ponies died, Mr Williams has yet to comment further.

The New South Wales Department of Primary Industries said while it was aware of the incident, it was not part of the ongoing investigation, as the deaths themselves occurred outside the state and “there was no evidence of infectious disease”.

The Australian Maritime Safety Authority and the Victorian Agriculture Department have referred the ABC to DPIPWE.

“All circumstances surrounding the deaths of the horses are being considered as part of the investigation,” a spokesman said.

“The department is liaising with interstate authorities and has obtained pathology reports which are being reviewed as part of the overall investigation.”

The operator of the Spirit of Tasmania, TT Line, will not comment either, other than to point out the initial investigation was “satisfied that the vessel appears to have complied with AMSA requirements relating to the carriage of livestock”.

Cloud hanging over leisure horse market

Ms Sheehan transported 70 horses on the ship in the past week, after the Magic Millions yearling sale and ahead of Wednesday’s Launceston Cup.

She said while it was largely “business as usual” for her operation, the leisure horse market was being severely affected by the lack of information.

“People regard their horses like a child. They would do anything for them and they spend stupid amounts of money on them and people are concerned about this,” Ms Sheehan said.

“They’re concerned about why it happened and how they can avoid it.

“Until they release what the cause of death is and why they died, there’s this big cloud hanging over travel on Bass Strait.

“We’re getting to wits end with people ringing up constantly and going, ‘is my horse going to be OK on Bass Strait?’

“There’s too much unknown going on. I think there are too many people trying to protect their backside.”

It is not just the Tasmanian sector calling for answers.

As one well-placed figure in the mainland equine scene put it to the ABC: “there are a lot of highly regarded people in horse circles in this country who want to know what’s going on.”