Physiology of a Horse

Bar the Bull

Bar the Bull

At the Start
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Ladies,

Talk of Secretariat has me thinking.

There are three main factors which are believed to dictate how fast a human can run a distance race:

Lactate threshold
VO2 Max
Efficiency of running (or the speed at which the above two are reached)

Would it be possible to measure the above first two qualities in horses, with a view to buying good ones?
 
...dare say they can measure most things these days... assuming it's time and cost efficient to do so, as well as how much of a priority you want to make for it.
 
Heart size is measured and more commonly wind checked. Hearts grow at different times and rates so that can be misleading. In the states xrays are on file for each lot at the better sales.
 
That is interesting, but neither of those two factors are believed to have an effect on performance in humans. And I would guess that the factors I mention above would hold for any animal with a circulatory system like humans.
 
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You thinking of getting these tests done on existing racehorses or on unraced ones, Bar? The point Sheikh's making is that while lung capacity won't be enhanced over years, heart capacity (and thus its blood-pumping/platelet circulating ability) will be. You put the mask on an unraced 2 y.o., you'll get a different read than off a raced and training-fit 4 y.o., for example. The horse continues to grow and change until it's around 8, so it's not surprising.

You could still do these tests and find things are nifty until you see the horse in the flesh and see that its conformation is shite and that it will never run a tap due to a straight shoulder and pasterns. The tests would be markers towards performance, but the horse's build and mental attitude would be what really takes it forward.

In the case of someone like ATTRACTION, I've no doubt it was her highly competitive attitude which overcame her pronated knees and otherwise ungainly appearance. Her tests might've been great at 2, but nobody wanted to buy her because of the way she looked. So you'd have to take heart/respiration/conformation/action into account. And the conformation for a distance race would be similar for horse and human: think of an Ethiopian or Kenyan runner turned into a horse. You'd have a light-framed animal (even if it's tall) which might look all tendons and sinews - the opposite of the equine Usain Bolt you'd want for sprints. You'd have to see it in action, too - you might have perfect treadmill tests but see that once on course it thumped up and down like a piston engine - hopeless action for distance.

Putting internal organs' performances aside, it is anatomy which indicates best performance. I'm fairly tall, but even with my reasonably long legs, I don't have a long stride. I could, in fact, be out-strode by a shorter person with better hip action. Same-o for horses - conformation will determine action, and action will determine best performance over selected distance and going.

Narrow girth is bad news, all kinds of wrong ways with legs (you will not believe the types of wrong-shape leg bones you can have!), and however nicely the horse does on the treadmill, put it into the stress of real racing, and its flaws will find it out, regardless of perfect lactose and respiration. In fact, I would say that poor action will cause a quicker fade through lactic acid build-up than anything else. You can see that for yourself next time you watch a heavy-actioned horse trying to haul itself up a finishing hill - it may be look lovely, its lungs may be superb, but if its action is wrong for the job it's trying to do, it won't - can't - do it.

Further discourses available for £4.99 inc. p&p
 
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You thinking of getting these tests done on existing racehorses or on unraced ones, Bar?
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On an unraced horse. I am aware that these readings will change a time goes on, but it might give an indicator of future performance. I would guess that it would.

You could still do these tests and find things are nifty until you see the horse in the flesh and see that its conformation is shite and that it will never run a tap due to a straight shoulder and pasterns.
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Agreed, no test like this is going to be bombproof. Indeed the stuff you mention falls into efficiency of running in my list above, as would OtB's long legs. You will probably always find it hard to put science behind this.

Putting internal organs' performances aside, it is anatomy which indicates best performance.
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Agreed, and you will always have experts at the sales opining on this. But if we can measure internal organs' performance, and if it is important to performance, why should we put it aside?

I know sporting institutions like the British cycling team, and the Australian Institute of Sporting Excellence (or whatever it is called) test these parameters in their prospects as a matter of course. I am just wondering if we could do the same on equine athletes, to complement the type of expertise that you have demonstrated in your post, which I don't have.
 
Huh? Me... expert? Shurely shome mistake...

Well, how very lovely and fragrant to have such harmony on here! And, further, I wasn't disagreeing with you at all when I said 'putting internal organs' performance aside' - I just meant putting the info gleaned from them to the side while we looked at other factors, not dismissing them. They're very important, which is why horses are scoped regularly and any trainer worth his salt will check for other respiratory difficulties, such as flaps in the palate, polyps, etc.

I can't see why the tests would not provide indicators for future performance, either. (Oh, way too much agreement now!) Trainers are still using treadmills to increase stamina and keep lungs healthily active in horses which have suffered illness or injury, and there is a very comprehensive range of performance-enhancing remedies at their disposal, from BleedGuard (to prevent bleeding), digestive aids to help prevent abdominal polyps (very common stress-related condition in racehorses), to build up bone density in foals and yearlings, to aid blood oxygenation, you name it. So why not use the tests to show whether the young horse has got optimal internals.

If the externals are in good shape, the horse shows good internals, you should reasonably expect a decent performance. In fact, the internal engine is what supports the external frame - as we all know, lose your lung capacity and it doesn't matter how shapely your calves are or how well you can see, you aren't going to run very far.

Most enjoyable topic, Bar. Don't think I know of anyone who's kicked this off before - not that I've seen, anyway. I've hacked on about conformation in the past to the point where readers drifted into comas, but while one can't overstate the importance of having a well-assembled animal appropriate to the work it's supposed to do, I can't think of any of us discussing the internal workings. Excellent. (And that's as much agreement I can stand for one day. Let me go see if there's someone I can attack about something... )
 
Krizon - well put. What I was thinking myself along the lines of conformation and action being the basis of efficiency in running, but powered by good lungs and heart, which in turn are further developed by training and feeding regimes.

Good movement puts less strain on limbs, joints, muscles and all the bits that hold them together, which in turn means eaiser work for the heart and lungs, leaving more in reserve for when a stronger effort is required.

I suppose what you are really looking for is a balance of grace and power. The grace (i.e. action) would be intrinsic and evident from day one to an expert eye (although it can be marred by injury), but the power that drives it would be a product of the training regime and, as Krizon says, the organs providing it would be in various stages of development through each point of the horse's career.

Power and grace - just think of Nashwan cantering to the start of the Derby, rippling like a silk ribbon in a breeze.
 
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we touched very briefly on this subject in the thread that someone started when Happy died - but only in the sense that it would be interesting to see a study on hearts and internal organs health, and how they change as horses get older and still work....

Nice to see that its not such a weird idea !!!! :)
 
If you Google "Phar Lap's Heart" you'll see some fascinating sites, including one featuring photos of his heart, which was removed and is on display in Australia. His weighed 13.6 lbs, not as massive as SECRETARIAT's, but still nearly twice the standard.

Troods, you might know what such tests as Bar mentions cost? I would imagine that they'd be quite expensive in terms of not just taking the horse to the equipment centre, but in lab staff time, too. What would you think? Around £1,000, or considerably more?

The point, though, to take out of the Triptych's interesting article on SECRETARIAT is in the remarks made by its author: that even if you find a horse with a bigger heart (and one that passes the VO2 tests perfectly), it won't mean a tap if it's made badly or just hasn't got the competitive ability. I can't stress enough how conformation will determine the horse's action, and how that can be an indicator of possible future ills like sore feet, concussive injury, tendon and ligament tears and strains, stress fractures, to total breakdown.

The usual 'good' angle of the shoulder is around 45 degrees and the pasterns should be pretty close in matching the angle. Too-upright shoulders can result in what is called ventroflexion, which is where the back hollows out and the head comes up too high. This impacts on respiration, so that the horse will not breathe well. You may then get a trainer using a tongue-tie on the animal in the hope that it will breathe better that way, but it will be of little avail as the horse is literally not made right for the job.

You rarely get a too-sloping shoulder, but this sometimes causes such a horse to over-reach - i.e. the toe of the hind foot hits the back of the front foot or leg. (This also happens where the horse has landed steeply and hasn't yet managed to get its front feet out of the ground before the back ones follow; it's also common in very soft going, where the horse is swinging the hindlegs forward before the front feet have managed to pull themselves out of the mud. You often see front shoes ripped off this way, but it doesn't mean the horse's shoulder is wrong - in these cases, it's external factors.)

The desirability for a 'good' shoulder is the need for the scapula to be able to rotate freely at the gallop and for all front joints to be able to fold under the horse well if it is jumping. If the scapula is too upright, it won't rotate freely as its axis is limited, and this in turn will result in the front legs not folding optimally during the jump phase. In other words, they'll probably dangle a bit from the knee down - not really what you want in a chaser. However, an upright shoulder is no bar to excellence in the variety of competitive American 'walking horses' - in fact, breeders like them as the horses' action then becomes high-kneed and, while there is strong and visible ventroflexion, this is seen as part of the breeds' standard movement. It's just not something you would want for racing.
 
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redhead said:
...just think of Nashwan cantering to the start of the Derby, rippling like a silk ribbon in a breeze.
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Beautiful redhead... a more natural racehorse you never saw. Just about the longest stride recorded of any horse and agile too - they said he would run down the side of a house.

Appropriately named. Nashwan means to run "for joy"... he brought that joy to so many of us.
 
SteveM said:
Appropriately named. Nashwan means to run "for joy"... he brought that joy to so many of us.
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He certainly did, Steve. That canter to the start, I can still see it now. He just rippled over the ground. The epitome of grace and power for me, still.

Even Jimmy Lindley mentioned how beautfully he moved - "poetry in motion" I think were his words.
 
And for those of you entranced by the physiognomy of the racehorse, DEFINITE ARTICLE is apparently the most perfect specimen, tracing back to one of the most influential founding sires, the Byerley Turk. There is a book called The Byerley Turk written in a very irritatingly comma-less style by a chap whose name escapes me. The horse underwent the most rigorous training that Turkish cavalry horses had to pass before being allowed to take part in warfare. The final bit of an exhaustive exam was to be galloped through live shot and shell. Horses which jinked, refused, reared up, gave their riders a hard time, or bolted in t'other direction were all discarded. They don't make 'em like it any more!
 
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