Research delivering better understanding of thoroughbred injuries

The obvious challenge around this year’s spring carnival has been COVID-19, with immense uncertainty about health orders and on-course crowds in Melbourne. However, bubbling away in the background is the welfare aspect of this season’s carnival, in particular the need to get all horses safely through the Melbourne Cup.

The race has suffered in recent years from a worrying regularity of horses going amiss, a number that has reached seven since 2013.

Not all of these horses have died, and neither were all of them injured as a result of running in the race itself. In 2014, for instance, Araldo (GB) (High Chaparral {Ire}) was spooked by a spectator flag on returning to scale. He broke a leg and sadly couldn’t be saved.

Nevertheless, by last year’s race when Anthony Van Dyck (Ire) (Galileo {Ire}) broke down, the Melbourne Cup had an image problem.

In an Op-Ed for TDN AusNZ (which proved to be our most-read article through 2020), prominent owner-breeder Matthew Sandblom said, “I used to love the Melbourne Cup, but now I dread it”. He concluded that the race was ‘developing a tradition of providing ammunition for everyone who wants to bring the sport and the industry down’.

In response to the problem (and after a set of thorough recommendations delivered by an International Injury Review panel comprised of Victoria Racing Club Director and Godolphin Australia Managing Director Vin Cox, champion trainer Chris Waller and internationally renowned regulatory veterinarian Dr David Sykes) Racing Victoria introduced new stringent veterinary protocols this year for all international horses.

They require that all visiting horses be subject to veterinary oversight and screening, including a full-body scintigraphy and CT/MRI of distal limbs before arrival, and another CT before each start during the carnival.

The initiatives, which Racing Victoria hopes will set a new safety benchmark, were both welcomed and criticised when announced in April this year.

Speaking to TDN AusNZ last month, Irish trainer Joseph O’Brien, who has twice won the Cup, said the additional protocols had made life difficult in getting horses to the point of travel, and he admitted that he got pretty close to not sending horses at all.

“It was quite disruptive to the horses’ routines to spend time at an equine hospital in preparation for a big race, but those were the hoops that Racing Victoria set for us,” O’Brien said. “If we were to go, this is what we had to do and we just tried to manage it and deal with it as best we could.”

In the end, O’Brien sent two horses to Melbourne, including defending winner Twilight Payment (Ire) (Teofilo {Ire}), but the overall number of international nominations for the Cup this year halved to 15.

As of this week, the Order of Entry includes four horses that have gone through the Werribee quarantine system as international arrivals, down on last year’s figure of nine in the final field.

In part, this is due to the veterinary screening, which put off a number of regular visitors this year, but attribution can also go to COVID-19 and hotel quarantine, which has made human logistics especially difficult for the second year in a row.

Patching up horses

At the University of Melbourne, Professor Chris Whitton works in the Veterinary Clinical Sciences department. He’s a decorated professional, leading an equine orthopaedic research team from the university’s Werribee campus.

For years, he has studied lameness in horses and, in particular, the prevention of musculoskeletal injury. It’s a topical issue in world racing and, unfortunately, one that has given him plenty of case studies.

“Racehorse injury wasn’t always something that I concentrated on, but it became a prominent issue for me, particularly when I started training as a surgeon,” Whitton said. “One of the frustrations of being a surgeon is that you’re often just patching horses up, and I saw many really good horses having to be retired, or their careers heavily curtailed, because of limb injuries that might have been prevented.”

Whitton said that most vets are happy to treat injuries, to patch horses up, but he leaned towards that age-old adage of prevention over cure.

“Once you get to me needing to put an arthroscope in a joint or fix a fracture, it’s too late,” he said. “Those horses might come back, but they’re never the same horses they once were.”

The regularity with which Whitton was repairing horses led him to ask some simple questions: Why were the injuries occurring so much, and what could be done about them?

“Pretty soon, it became clear to me that these injuries were not all accidents,” Whitton said. “They were due to accumulated damage over time.”

Understanding high loads

The crux of Prof. Whitton’s current research has become this – accumulated damage over time (this research has been included in the Grayson-Jockey Club Research Foundation's 2021 funded research).

In 2015, the professor delivered a lecture that stated: ‘Trainers and onlookers might attribute these injuries to a bad step or fall, but when University of Melbourne researchers at the Equine Centre examined racehorse injuries post mortem, its vets found significant pre-existing microfractures in these joint surfaces.’

Whitton said this aspect was key to everything.

“If you apply repeated high loads to any material, it will eventual fail,” he said. “That’s the process of material fatigue, and bone has to obey the laws of physics, just like any material. Horses apply huge loads with every stride.”

Whitton and his team at Werribee have measured the load on the fetlock joint at a moderate gallop only. It’s the fastest they have gone during these tests, and they found a four-tonne load was applied on the fetlock-joint surface with every stride.

Given that horses travel much faster than a moderate gallop in the closing stages of a race, and the variables at play include the surface of the racecourse and distance travelled, it's a serious figure.

Microfractures that occur in bone are not harmful individually.

They can be tiny, and they occur across all horses in competition and recreational use. But repeated high loads from training and racing are problematic, and obviously increase the risk of major injuries later on. Whitton believes the solution was re-addressing attitudes to training.

“Training periods can be too long and resting periods too short,” he said.

Rethinking training

The research team has found that the injury problem is often cyclical.

In the case of horse racing, trainers might identify a problem with a horse, such as soreness or lameness, and the horse is put out to rest from its high-load environment. During spelling, the bone repairs itself, the horse presents as sound and is brought back into its high-load environment. The cycle begins again.

“We’re resting horses regularly, yes,” Whitton said. “But the rest periods might not necessarily be long enough.”

He said that many horses regularly cope with their training regimes, but his research indicates that many also don’t.

“Because of the high prevalence of joint injuries in horses, there’s a large portion of horses that aren’t coping with it,” he said. “It doesn’t mean that rest periods have to be longer. It just means that the balance between risk and high-level training is not right.”

Whitton said that managing this can be done in a number of ways for trainers.

Multiple periods of short rest are beneficial, or longer periods of rest when spelling. Professor Whitton said it wasn’t necessarily critical how trainers did it, but it was vital that there was increase in the net amount of time horses were spelling.

“Alternatively, you might train them less intensively, so then you can train for longer if you train less intensively,” he said. “But the bottom line is that the life of the bone is finite, so you have to keep that in mind when you’re managing horses.”

Faster horses, greater risk

Whitton’s research doesn’t take pedigrees into account when it comes to thoroughbreds. He doesn’t consider that hardiness might be attached to genetics.

“My attitude is that it doesn’t matter what you’re presented with, you then have to manage that,” he said. “In biology, there will always be a range, and a big variation between what different horses can cope with.

"Some of that may be due to breeding, but there are a whole lot of other factors that play into it too. You still have to manage a horse as an individual, and manage the workload that it gets.”

Whitton said the problem won’t be solved by breeding hardier horses.

“It’s probably one of the issues,” he said. “You could breed a particularly injury-resistant horse, but it’s probably not going to be very fast. Again, our data suggests that it’s the better horses at risk of injury, which is not surprising because better horses go faster and create larger loads on their skeletons.”

Whitton’s research into this complicated field predated 2013, when things in the Melbourne Cup began to go wrong after the death of French raider Verema (Fr) (Barathea {Ire}). Almost each year since, there’s been an incident.

“We were already working on these issues years before,” Whitton said. “Thereafter, the level of our funding increased because the racing industry saw the need to understand these things better. And so our workload increased, as did our efforts into trying to understand what was going on.”

In more recent years, Whitton said their everyday veterinary practices have escalated. He and his team are consulted by Racing Victoria whenever new policies on welfare are afoot, and they’ve had to do a lot more imaging.

Also, there’s been a wider interest in their work, and with this comes heightened cooperation.

The team relies on post-mortem subjects, and every horse that dies on a metropolitan racetrack in Melbourne (the current statistic in the state is less than one death per 2000 starts) must go for analysis, while a number of trainers allow the team to use their horses for various research.

But what does Professor Whitton hope his research will achieve?

“The ultimate aim is how to safely train a horse to do what it has to do,” he said. “We’re aiming for some general recommendations about how you train a horse safely, but also how you then monitor the horse’s response to that and adjust as you go.”

Whitton said he and his team were trying to create general principles about how horses might be trained safely and still perform at their maximum without risk of injury.

And are people listening?

“They definitely are,” he said. “I’m always encouraged when I do presentations to trainers that there’s a lot of interest and lots of questions, and lots of intelligent questions too. There’s certainly a very good young brigade of trainers coming through that are very interested in a more scientific approach to training, and that gives me encouragement.”

As to the future of the Cup, Whitton said they would learn more every year.

“There’s going to be more monitoring of horses, as there has been this year,” he said. “Hopefully we’ll get a better understanding as time goes by as to which of the horses are at risk, and we can then modify or bring in certain regulations, or educate trainers, to ameliorate those risks.

“The bottom line is that it’s all about risk mitigation because you’re never going to remove it completely, but it is about reducing risk where we’ve got good evidence to implement certain practices.”