Australasian study aims to provide x-ray clarity

Cover image courtesy of New Zealand Bloodstock

New Zealand veterinarian Dr Frances Peat has been leading two crucial studies, one based on nearly 4000 horses sold through New Zealand Bloodstock, and another on nearly 3000 sold through American sales companies Keeneland and Fasig-Tipton.

The American study focusses on two key aspects, sesamoiditis and stifle cysts, while the New Zealand study, which also has significant ramifications for Australia and Hong Kong, where many of these horses end up racing, takes a much broader look at all 36 radiographic findings and measures them up against race performance.

Pre-sale x-rays have been an increasing point of contention among those in the thoroughbred industry, as highlighted in two recent articles in TDN AusNZ, which canvassed the opinions of sellers, agents, buyers and leading vets.

Dr Peat said she believes much of the contention has been driven by the significant improvement in the quality of radiographs in the digital era.

"The x-ray technology has outpaced the rate that the research can be done. A lot of the debate is because we see so much from what comes through on the digital x-rays and it's just a case of now working through what of the detail we see is relevant to race performance and which has no influence," she told TDN AusNZ.

"The whole reason for doing these studies is to try and benefit all parties involved in the sales process. The main thing is to give people more evidence-based information in which to base their decision. It’s been designed in everyone's best interests."

Dr Peat believes the level of work involved in conducting a study of sufficient depth to produce meaningful findings is why it has taken until now for a study of this scope to be undertaken in Australia or New Zealand.

It was only her specific circumstances including her involvement with Colorado State University in the US, which has allowed Dr Peat to pursue a dual study approach.

"In 2015, when I left New Zealand I went to the States to do some specialist training, but also having done the racing and sales work, I knew that these questions needed to be answered," she said.

"It’s too much of a job to be done while you are in private practice. Being based at a University with the research reputation to be able to take on and do this study helped a lot."

Two studies conducted in parallel

While the US-based study was funded by the sales companies, as well as the Grayson Jockey Club Research Foundation and several private donors, the incorporation of the second Southern Hemisphere study was only possible via a grant from the New Zealand Equine Research Foundation.

"That study is due to be finished by the end of this year with results to come out next year. The New Zealand study involves almost 4000 horses, 3778 yearlings which were sold through the New Zealand Bloodstock sales at Karaka over a three-year period," she said.

"We have had backing from New Zealand Bloodstock, all of the New Zealand equine clinics involved in the sales radiographs as well as the Hong Kong Jockey Club, to go ahead with it."

To do the sort of study to the scientific standard that is required, the New Zealand study has involved all x-rays being read and assessed from scratch by the research team.

That has been quite an undertaking, when you consider it is assessing 36 different radiographic details, plus incorporating additional information from x-rays taken if the horses have been sold as 2-year-olds or given pre-sale x-rays before being sold to Hong Kong.

"We are also incorporating surgical certificates, to indicate if the horse may have had surgery," Dr Peat said.

"Racing performance is the key outcome measures, and that goes up until the end of their 4-year-old racing season, which is why it takes the time it does to conduct the research.

"These are real world studies, which aren't controlled in the lab, so there are obviously plenty of things that will influence whether a horse races or not, completely independent of the x-ray findings. That's why we have incorporated such large numbers, so we are able to give the best idea possible of any association between x-ray findings and racing performance."

Measuring racing performance

The racing performance factors taken into consideration are ones which have been previously determined to provide a standard which can be applied to research.

"We've got a whole list of things we are judging race performance by. The first of them is whether they managed to start a race or not, and if they started a race and then for each racing season we are taking into account a raft of factors such as number of starts, number of wins, number of top three placings as well and then what class they raced at," she said.

"All of those things get taken into account and then get put into a model, so with the data analysis, you run a regression modelling, so you can work out which of those outcomes might be associated with certain findings."

Due to variations in prizemoney levels across various jurisdictions, earnings are not generally incorporated into race performance, while for a select amount of horses which have raced in Hong Kong, the study has been able to assess clinical information throughout their careers.

American study hones in on suspensory and stifle issues

The American study, which focusses on the specific issue of suspensory and stifle cysts, has been conducted by the same team to same standards, albeit with slightly different methodology. While there are specific regional factors which influence outcomes in the United States as compared to New Zealand and Australia, Dr Peat feels the study will be also useful in this part of the world.

"They are separate studies but are run by the same investigators. We have used the same grading system for both, which means that the results will be able to be compared. There are differences between how horses are raced between here and over there, but the studies are linked. There is value in that too," she said.

The American study not only involved sourcing radiographs, but also conducting ultrasounds focussed on the suspensory branch. Obtaining permission from consignors to conduct pre-sale ultrasounds was challenging, but the team was able to get a 74 per cent participation rate.

It was that process of speaking to consignors which proved particularly encouraging for Dr Peat and her team as it became apparent of how much the industry wanted the level of clarity which these studies hope to provide. That level of enthusiasm has also been evident in the New Zealand study.

"Hopefully, this can give at least a bulk of data that has never been compiled before and it should give us some more evidence-based results," she said.

"It will go through the scientific process of being per reviewed and being held up to the world class standard and we know that will be accurate as possible."

Release of results crucial to study success

The team is working through the data aspect of the studies at the moment with a view of completing that by the end of the year, with the review then to be conducted before the likely release of results around this time next year.

Responsibility will then fall to Dr Peat and her team to provide a proper platform to ensure that the results are received and understood by those who can get most benefit from them.

"I'm starting to feel the responsibility to get the results out there. There is a lot of good research that gets done which never sees the light of day in the public and I think this work will only have value if we can provide useful information," she said.

"It will be nice to get to the end of tens of thousands of x-rays, but what I am really looking forward to is being able to share that information with people that will hopefully minimise some of the contention that goes on."