How science, scans and stubborn vets changed the Melbourne Cup forever

Cover image courtesy of Victoria Racing Club

For seven days, one horse’s spring hung in the balance. CT scans had flagged Sir Delius (GB) as a heightened injury risk - enough to rule him out of both the G1 Melbourne Cup and as a byproduct, the G1 Cox Plate.

Hoping for a reprieve, Gai Waterhouse and Adrian Bott took up Racing Victoria’s offer of more advanced PET scans, but results confirmed the initial finding. By mid-week, the colt was back at Tulloch Lodge and, after briefly appearing in Randwick’s Craven Plate nominations, officially headed for the paddock.

A dual Group 1 winner in his second Australian preparation, Sir Delius had been well favoured in ante-post Cup betting markets, and for a moment, it was speculated that his trainers were going to challenge his scratching. Their change of tune in the days since indicates an acceptance of Racing Victoria’s decision, and an acceptance that the horse’s welfare must come first.

A thorough process

Sir Delius’s case isn’t an isolated one. Since Racing Victoria overhauled its Cup-week vetting process after the 2020 death of Anthony Van Dyck (Ire) (Galileo {Ire}), advanced imaging has become the most powerful tool in preventing catastrophic injuries.

The death of Anthony Van Dyck marked a turning point for Racing Victoria. It was the sixth Cup fatality in eight years; five from catastrophic limb fractures.

In a report delivered the following year, 41 of 44 recommendations were implemented ahead of 2021 - all but shortening the distance, shrinking the field, and capping overseas runners.

“You can't ever say you're going to completely eradicate risk in any way in horse racing, but what we've said about the whole structure of the protocols is they are there to mitigate the risk that's identifiable," said Racing Victoria’s Executive General Manager - Integrity Jamie Stier, who has been in his role since 2018.

"And by identifiable, we don't just mean what we can see externally."

Those reforms have sparked almost as much debate as the fatalities that prompted them. Some owners and trainers argue the protocols have become too heavy-handed - ruling out sound horses and thinning the fields of Australia’s biggest races. Even stemming conversation that it will change the landscape of bloodstock purchasing.

But not everyone inside Racing Victoria agrees that the system is overly strict.

The Herald Sun recently reported that Racing Victoria’s long-time General Manager of Veterinary Services, Dr Grace Forbes, lodged a bullying application with the Fair Work Commission, alleging she was pressured to clear international horses considered at “high risk of catastrophic injury” to race. In her submission, Dr Forbes claimed senior executives, including chief executive Aaron Morrison, and Stier, urged her to be “flexible” in applying safety standards - something she says conflicted with her duty to equine welfare.

If substantiated, the allegations suggest internal tension not over the existence of the protocols, but over how firmly they are enforced - a contrast to the external calls to relax them.

Racing Victoria strongly refutes the allegations, describing them as inaccurate and disparaging. “Equine welfare is of the highest priority,” a spokesperson told the Herald Sun, noting the organisation has spent more than $45 million on welfare initiatives since 2017.

A Fair Work Commission hearing on Dr Forbes’s application is expected later this year.

In terms of the protocols, the greatest changes were made to the vetting process, which was expanded significantly. As Stier puts it, “it’s all about getting as much information as we can to assist the decision-making process.”

International horses entering the Cup from 2021 have to adhere to the following process:

Domestically trained horses are subject to pre-race vet inspections and a mandatory CT scan once before the Cup, as opposed to every race start in the campaign.

This year, Racing Victoria’s authorised vets for Cup inspections are internationally renowned veterinarians Dr David Sykes and Dr Amanda Piggott, whose extensive experience in Europe makes them a familiar face to the connections of many Cup hopefuls.

Each thoroughbred veterinary examination covers all bases from listening to the horse’s heartbeat and lungs, to palpating and flexing limbs. The intention is to have each examination three weeks apart, to get a picture of the horse’s movement over time.

This is where the Sleip app also comes into play. Dr Sykes and Dr Piggott can review footage taken by the stable and compare to what they witness at each examination.

“Sleip is not a decision-making tool on its own, it's used as an aid to assist in those decisions,” Stier said. “By creating a library of the horse being trotted up, you benefit from having several reference points along the way to compare to and notice if there's changes in the horse’s action.

“More and more trainers are using these different types of technology in their day-to-day operations, as well as wearable monitoring devices, to assist them in the preparation of their horses.”

Both the imaging from the horses’ home countries and the imaging taken in Australia is sent to three vets for review; from a panel of five veterinarians - two from Australia, two from the United States, and one from Britain; three are selected at random to assess each horse.

Each vet must come to their conclusions independent of one another, and the identity of the horse is anonymous to the panel.

“They are not aware of who else is assessing the same horse as them, and they don’t communicate with one another on their findings,” Stier said. “They individually submit their reports to Racing Victoria, where our veterinary team can make a final assessment."

The window for the final pre-Cup CT scan opens on the Monday before the G1 Caulfield Cup, and closes on the Thursday before the Melbourne Cup to allow a sufficient window of time for the vet panel to make a decision and for horses to be clear of sedation traces before racing.

“Year on year, we've been working more and more to try and communicate the process better with the connections of horses,” Stier said.

“The stewards and the veterinary team will make the final decision, but something we are very conscious of this year is sharing information with connections so they are aware what has been relied upon to make those decisions.”

Evolving each year

Trainers privately admit the process can feel opaque - when scans flag microscopic bone changes invisible to the naked eye, even the best horsemen are left waiting for a verdict they can’t see.

Each scan is assessed for signs of bone being under stress and, where remodeling is taking place, areas of bone where resorption of damaged bone is outpacing the rate of new bone being laid down.

“We're looking at ways that we can obtain the best information available to us to assist in making the decisions,” said Stier.

Part of that process has included acquiring a PET scanner at the University of Melbourne, which is currently the only one in Australia of its kind. This technology is available as requested by either the vet team or the connections of a horse, as in the case of Sir Delius.

PET imaging is a form of nuclear imaging where a small amount of nuclear isotope is injected into the horse, which is then picked up by the scanner. Nuclear imaging has drawn criticism from both owners and trainers for its perceived health impacts on the horse, but the reality is that the nuclear isotopes most commonly used in PET and similar imaging procedures are extremely low risk and are almost completely removed from the body within 24 hours.

Racing Victoria trialled the technology in the spring of 2024 and were happy enough with the results to make PET imaging more available in 2025.

CT scans were available before 2021, but their use was more on an “as needed” basis, as opposed to a mandatory part of the process. As the technology has become more readily available throughout Australia and worldwide, it has become the preferred technique for Racing Victoria.

“The protocols concerning health declarations and veterinary assessments were previously in place,” said Stier. “We have implemented further pre-export vetting as well as mandatory imaging as the technology became more readily available worldwide and we were able to benefit from its use.”

Scintigraphy, another form of nuclear imaging, was originally introduced as mandatory imaging in 2021, but it is now only used as deemed necessary by the vet team.

“Scintigraphy is a much more arduous process than a PET or CT scan,” Stier said. “It’s a full body scan, and from what we were seeing, it was primarily lower injuries that were causing the most concern. Other modalities such as CT scans are the most appropriate imaging for the areas that were creating the greatest concern.”

Even before the new protocols were in place, CT scans were saving lives. In 2019, Hugh Morrison’s Marmelo (GB) (Duke Of Marmalade {Ire}) was scratched ahead of the Cup, a decision deemed controversial after connections’ UK-based vet Dr Ian Wright disagreed on the extent of the lesions found in two of the horse’s legs. Despite connections maintaining the horse had no issues, Marmelo never started again, and was retired to stand at Haras du Grand Courgeon a week after the running of the Cup.

Maybe the vets are right

If the process feels cautious, results suggest it’s justified.

Since the changes to protocols in 2021, at least 10 horses have been scratched from the Cup due to the results from scans.

The subsequent career of Jan Brueghel, whose scratching caused outrage from his trainer Aidan O’Brien, remains an interesting case; while he was one of the fastest back to the races with a 210-day break between starts, it was initially planned that he would go to Hong Kong’s Champions Day meeting in December after his Cup scratching.

When his name didn’t feature amongst nominations for the meeting, O’Brien told media that he didn’t have sufficient time to prepare the valuable colt for the meeting and instead he would likely start at the Saudi Cup meeting the following February. Instead, the entire didn’t emerge until April at the Curragh and has only raced three times in 2025. He was fourth at his last start in July.

O’Brien, who trained two of the horses euthanised in recent runnings of the Cup, vowed in 2024 to never send over another horse to the Cup. He entered boom colt Scandinavia (USA) (Justify {USA}) in the 2025 edition before withdrawing him from entries in late September and sending him to the paddock.

According to racing.com’s Michael Felgate on his program The Verdict, Scandinavia had begun the Cup vetting protocols, but it is unclear the extent to which the colt had been vetted before withdrawal.

Then there are horses who have taken a break after following results provided by a scan ruling them out of a race, including aforementioned Gold Trip who returned to win the race.

Without A Fight (Ire) (Teofilo {Ire}) competed in his first Melbourne Cup in 2022, finishing mid-field, and was subsequently scanned ahead of a potential G2 Zipping Classic start, in line with protocol for internationals. When those scans picked up changes from his pre-Cup scans, he was sent to the paddock and saved for the following May, where he would go on to win four out of five starts, culminating in the Caulfield-Melbourne Cup double for Anthony and Sam Freedman.

Danny O’Brien’s Young Werther (NZ) (Tavistock {NZ}) was denied a run in the 2021 Cup due to his scans and spent more than 10 months on the sidelines before returning to the races. He has since raced 34 times for four wins and several Group 1 placings, and remains in training this spring.

Four years on, the results speak for themselves: no fatalities during the Melbourne Cup Carnival since the introduction of mandatory imaging. The protocols are doing what they were designed to do - protect the horse first. The only remarks in the stewards’ report from 2024 mention an abrasion to the heel of 22nd-placed finisher Saint George (GB) (Roaring Lion {USA}).

But they’ve also changed the landscape. Horses are now being ruled out of spring features at a rate few could have imagined a decade ago, and the attrition among Cup hopefuls - both international and local - has reshaped how trainers prepare and campaign. For some, that’s the cost of progress. For others, it’s proof the pendulum may have swung too far.

The ongoing Fair Work Commission case brought by Racing Victoria’s chief vet, Dr Grace Forbes, has only amplified the debate: how cautious is too cautious, and who ultimately carries the weight of that decision?