Cover image courtesy of Ashlea Brennan
Part one of a wider look into the 2-year-old landscape featured differing perspectives on the merits of racing thoroughbreds in their 2-year-old year. Gai Waterhouse spoke of her desire to see more 2-year-old racing in the program, while John Messara believes the programming is right, and voiced concerns about the longevity of some horses that race at two. The Thoroughbred Report spoke to Professor Chris Rogers, to gain a better understanding of the biomechanics behind a 2-year-old horse.
Closing in on 30 completed research projects across a career spanning decades, Professor Chris Rogers is one of the most respected members of the thoroughbred veterinary community.
Passionate about his work, Rogers spoke to The Thoroughbred Report around the musculoskeletal systems of thoroughbred racehorses, and shared his views and research on the potential advantages of racing at two.
Mobile from week one
It will likely come as little surprise to a number of people reading this piece that horses are fundamentally mobile creatures. Even a brief foray into social media with a search of 'horse in paddock' will unveil a litany of photos and videos of thoroughbreds charging around, trotting and bucking.
But does this interest in activity develop over time, or is it instinctual? According to Professor Rogers, it's the latter, telling The Thoroughbred Report, “The simplest thing is that, and I often use this as an example for teaching, a lot of what we do with horses is underestimate the amount of exercise that they should have, rather than over (estimate).
“The simplest thing is that, and I often use this as an example for teaching, a lot of what we do with horses is underestimate the amount of exercise that they should have, rather than over (estimate).” - Professor Chris Rogers
“Particularly if you look at how precocious a foal is, they’ll stand within an hour of birth, and within a week of life they can cover seven kilometres, just walking and cantering beside its dam.
Arrowfield foaling staff walking mares and foals back to their paddock | Image courtesy of The Image Is Everything
“It’s so different to a human baby, and I think that’s one of the big problems we have with people from outside the industry looking at 2-year-old racing, they all look it and say, ‘Oh 2-year-olds, they must be babies’ but when you look it at, that animal has been moving around, covering significant distances since it was a couple of days old.
“So it (the horse) is completely geared for getting up, moving and exercising, and we often underestimate just how much exercise a horse actually needs to develop properly.”
Filling their frame
In part one, Gai Waterhouse spoke about you can't make a horse be a 2-year-old, they either or are they aren't. Plenty of her younger horses clearly are, with her and co-trainer Adrian Bott training 33 2-year-old winners in the 2022/23 racing season, more than any other training operation in Australia.
Even if a horse isn't going to make it as a 2-year-old (for the 2021/22 season, there were 2721 individual 2-year-old starters in Australia, compared to 7528 individual 3-year-old starters), Professor Rogers is a believer that early development is vital to a horse's longevity, saying, “Growth spurts are fairly consistent across species, but in the horse, there’s a four, five fold increase in body weight by the time it’s a yearling. There’s massive naturalisation, and when we start talking about that window, we get up to weaning, there’s rapid periods of vertical growth.
“Then we start talking about the idea of what’s occurring between 11 and 24 months, that’s basically the bones, the leg bones that are attached at the body, above the knee and above the hock, and we’re talking the humerus, the scapula, they’re the ones doing the growth in that phase.
Equine anatomy | Image courtesy of Wikipedia
“So when you start to look at and when you start to say, ‘When does growth or vertical height stop in the horse?’, you look at those radiographs of the growth plate, which are pretty crude indications in termination of growth. When you look at the bottom of the radius, where it joins onto the knee, that’s the last one in the leg to close and give us an indication of growth.
“Radiographic evidence tells us that by the time a horse is 24 months, in the majority of horses, that’s closed, so that tells us pretty convincingly that longitudinal bone growth has finished, and if we don’t provide the right stimulus at the right time, the body grows up going, ‘I’m not going to do anything’.
“Radiographic evidence tells us that by the time a horse is 24 months, in the majority of horses, that’s closed, so that tells us pretty convincingly that longitudinal bone growth has finished...” - Professor Chris Rogers
“It doesn’t have that developmental pathway to respond appropriately when you start exercising it, so it’s one of those interesting things that you’ve got to have growth, but you’ve got to overlay the appropriate amount of exercise to create that development.
“We’ve been playing with some other species, lambs and cows of all things, with what’s called developmental programming, and we think that’s one of the things that’s occurring (in horses) when you provide exercise, particularly when you’re talking about yearlings and getting them going.
“Some of the changes that you see in the bone and the cartilage is a physical, direct response to exercise load, and some of the bits you can’t see is where you’re actually upregulating the basic biological systems within those tissues and you’re training those systems with how to respond when that animal starts doing more advanced work.
Morning trackwork at Flemington | Image courtesy of The Image Is Everything
“Exercise improves the tissue, but it also has the effect of upregulating the tissue so it’s heading in the right direction, so when you subsequently impose more gallop work it goes ‘been there, done that, I know what to do, this is how we respond to that type of stimulus.’”
The art of timing
One of Professor Rogers' most significant pieces of research is the 2013 publication, The association of 2-year-old training milestones with career length and racing success in a sample of Thoroughbred horses in New Zealand. In this, Rogers focused on the 'milestones' of training a thoroughbred; the education process, the first barrier trial, and the first race.
Discussing his work, Professor Rogers said, “When you look at the 2-year-olds, we did that in a study in New Zealand, we looked at those milestones, that study has been repeated in Australia and the same in the United Kingdom, and it’s exactly the same data.
“The earlier you start exercising and the more advanced that exercise is, the differences are being started, to having a trial, to having a race start, the greater the positive effect that there is. So it starts to tell you that the horses are very capable of racing as 2-year-olds but it also says that racing as 2-year-olds primes their system for racing as 3-year-olds, the tissue is still receptive and responsive.
“So it starts to tell you that the horses are very capable of racing as 2-year-olds but it also says that racing as 2-year-olds primes their system for racing as 3-year-olds, the tissue is still receptive and responsive.” - Professor Chris Rogers
“The tissue organises itself to be heading in the right direction so when you apply more gallop work it responds positively, rather than going ‘this has never happened before’. The nicest example of that is if those foals were reared in an open barn, the cartilage had never been exposed to a variation in load, so it never changed. It never developed the ability to tolerate loads when galloping.
“That’s part of what happens when you start with a 2-year-old, you get them started, then you get to trial start and then to a race start, there’s variation in the loads across the fetlock joints, it’s much greater. The tissue responds, it goes ‘I now know! I’m not just standing around, I’m actually doing something’, whereas if you took a horse and then started working as a 4-year-old, unless it had galloped and done something in the paddock the tissue would never know what it’s like to experience the loads of galloping, so it wouldn’t be prepared for it.
Gallery: Winners of some of the early 2-year-old stakes races this season, images courtesy of The Image Is Everything
“It’s really interesting, if you foals and the way they behave around their mothers in the first month of their life, it’s quite cool. They start, they suckle and follow mum around, and then they start trotting and cantering in ever-increasing circles. Then they start going for gallops and slamming on the brakes, by doing that it’s priming all the muscles, tendons and cartilage into a variation of load.
“With horses, if you haven’t worked them for a bit they go for a hoon and a bit of a galah in the paddock, and I often wonder if there’s some internal process in the horse that makes them go ‘in order to keep my bone at optimal strength, I’ve got to give it some of these load cycles’.
“... I often wonder if there’s some internal process in the horse that makes them go ‘in order to keep my bone at optimal strength, I’ve got to give it some of these load cycles’.” - Professor Chris Rogers
“It’s part of why horses inherently have those play characteristics, it’s one of those interesting things, there’s got to be a reason for it from an evolutionary point of view or a biological point of view, there is this inherent pattern to doing things.”
Putting welfare at the forefront
Equine welfare is, rightly, a major focus of the industry currently, and Rogers is a firm believer that 2-year-old racing has its part to play in ensuring stronger outcomes across the board, saying, “You’ve got the fundamental issue in the racing industry with horses that are just too slow, but the primary reason that we lose horses out of the racing industry is due to injury, musculoskeletal injury.
“If you have a horse, and you start it and race it as a 2-year-old, particularly if you race it as a 2-year-old, even if you take out the 2-year-old part of their racing career, they have longer and more successful careers than horses that start later.
“So it starts to tell you that it fits within that biology, if you want to improve that productivity and resistance to injury, then starting horses at two is the ideal way to do it.
“... if you want to improve that productivity and resistance to injury, then starting horses at two is the ideal way to do it.” - Professor Chris Rogers
“If you don’t start them as a 2-year-old, you’re already creating an issue for the horse, whereas if you do start them at two, you’re trying to optimise that horse’s potential within the industry.
“It’s an interesting one, despite the science, there are still a lot of people saying, ‘You shouldn’t be doing that’, when you think about the biology underneath it, they go for a galah and a hoon every now and then, they’re all doing this sort of thing. What we’re doing with horses as 2-year-olds actually isn’t contrary to what horses naturally do, it’s actually fitting in and we’re working with the horse, not against it.”
