COLE HARDEN (centre, Gavin Sheehan) beats SAPHIR DU RHEU (right) in The Ladbrokes World Hurdle after wind surgery. Cheltenham 12 Mar 2015 - Pic Steven Cargill /

What about wind ops?

The pursuit of optimising ability in racehorses has stepped forward in leaps and bounds through the past decade. Training methods, pharmaceuticals, and surgical intervention have all progressed apace in the quest to squeeze every drop of talent from ever more expensive thoroughbreds.

But, from a wagering perspective, these advancements are largely hidden from sight: there is no official record of injuries; training patterns are discernible only from a deep dive into the form book; and the influence of veterinary care is entirely 'black box' for the average punter.

One vulnerability in racehorses, especially in larger ones, is a difficulty breathing when under significant pressure from exercise. Technically known as DDSP (dorsal displacement of the soft palate), it is the temporary movement of a piece of fleshy tissue into an area through which oxygen flows. In other words, it causes a restriction to the amount of air a horse can breathe in during the business part of a race. Seeing as oxygen is needed to keep the muscles working, this is a bit of a problem.

Those who raced horses historically sought to address the issue via a procedure called tubing, whereby, as the name suggests, a metal tube was placed directly into the airway allowing air to bypass the obstructed area. However, tubing became outmoded with the evolution of internal surgical procedures and, in October 2012, 'tubed' horses were no longer permitted to race in Britain.

Whilst, as usual, there were derisive howls at the time - change is always greeted in such a way in the racing fraternity (and, in fairness, in most other walks of life) - the rise and rise of the 'wind op' quickly ensured that horses hindered by breathing difficulty during racing had another potential mitigant.

There is an array of possible interventions which vary in gravity; and, until the beginning of this year, the general public had no awareness as to which horses had had surgery, still less which procedure was undergone. Happily, and partly as a result of calls from the Horseracing Bettors Forum, a group attempting to improve the lot of British punters and which I currently chair, the BHA fended off the Luddite clamour from within racing to pronounce that, from January 19th, wind surgery (in its generic form) was required to be declared at the time of entering the affected horse.

There was the usual dissent from within the ranks, including from otherwise sensible and generally cautious individuals such as the excellent Gary Moore, who proclaimed, "It will be about as much use as an ashtray on a motorbike, a complete waste of time."

In fairness, many of his peers took a more pragmatic stance, and punters (and breeders and other owners and trainers) have been aware of the vet's intervention for ten months now. Whilst the public is not privy to exactly which operation has transpired, it is generally reasonable to assume that the appropriate level of procedure for the affected animal has been undertaken.

So, ten months in, what do we know?

Let's start with the caveats. As mentioned, we don't know which procedure took place and, naturally, all procedures are not alike. So it may be that intervention A has a much higher success rate than interventions B or C. At time of writing, we must assume that proportionate action was taken and that the outcome of that proportionality across the impacted population is the same, by and large. That may very well not be a correct assumption, but in the land of the blind and all that...

Secondly, ten months into this new degree of awareness, we are still dealing with a relatively small sample size. From January 19th to November 18th there were 4,007 UK runs by horses which had had wind surgery. To be clear, that might be the first or 21st run after surgery. That is in the context of 79,861 total UK runs, which is as close to 5% of all runners being impacted by wind surgery at some point as doesn't matter.

On that point, a third proviso. I have yet to see two wind surgery data sources with the same numbers. We've done a good amount of work with ours, and I'm pretty confident that our data are cleaner than other sources I've seen; but it may very well not be precisely perfect. That doesn't really matter when looking for general patterns: this information will never be used to inform a life or death situation, but it may lead a punter to weight in favour of one horse over another. And it may not. The ultimate caveat is caveat emptor: your money, your choice. As always.

OK, scene set, what of the data?

Overall performance by runs since a wind op

Here is the overall picture, in terms of win strike rate by run number after wind surgery. Again, for the sake of clarity, 1 is first run after surgery, 2 is second run after surgery, and so on; 0 means the horse has not undergone wind surgery.

Win strike rate, by runs after wind surgery, all UK runners 19/1/18-18/11/18

Win strike rate, by runs after wind surgery, all UK runners 19/1/18-18/11/18

I wanted to start with a chart because I think it shows a quite interesting pattern, viz. the slow but steady improvement in the win strike rate of horses who have undergone wind surgery, up to their fifth post-surgical run.

That fifth start column looks an anomaly, and in the absence of any sensible theory to explain its high performance, I'm happy to ignore it as such.

Here is the tabular version, this time with other data elements presented:

Table view of horse performance by wind surgery run, 19/1/18-18/11/18

Table view of horse performance by wind surgery run, 19/1/18-18/11/18

It may be interesting to note that, on first run after wind surgery, while the win strike rate improves, the place rate is notably lower. Again, I'm not sure whether this is anything but an anomaly, notwithstanding that there are over 1100 runs in the sample. Generally speaking, horses who have undergone wind surgery place at a slightly higher rate than whose which have not, but not necessarily on that first run post-intervention.

In truth, what we see here is that there is little more than a marginal gain overall as a result of wind surgery. But there are just about enough data to look into sub-divisions of the superset, so let's do that.

Impact of wind surgery by race code

The first cut of the data I'd like to review is by race code and, specifically, comparing flat races with jumps races. Now, check this out:


The starting point - left hand side - of the line is the control, i.e. no wind surgery for the horse. National Hunt (NH) horses strike at a slightly higher rate generally because NH races have fewer runners generally. But look how the lines diverge as they move away from the control.

The orange line, representing performance by number of runs since wind surgery in flat races, gets progressively worse and never out-performs the 'no intervention' control group during up to four subsequent starts.

Conversely, the blue line shows that the impact of wind surgery on National Hunt runners is increasingly positive up to the fourth run subsequently (and indeed beyond, not shown here).

The pattern of the data is clear but explaining it is less straightforward. My best guesses are that a) the selected interventions on flat horses are of the more cosmetic type, or at least at the lower end of the range of procedures available; and/or b) that wind surgery in flat horses is a 'desperation measure' when an exasperated - and doubtless notably less wealthy than pre-purchase - owner has exhausted all 'homeopathic' options.

I couldn't say that either of those theories is credible, and perhaps you have an alternative to throw into the mix. If so, do please leave a comment below to that effect.

Impact of wind surgery by length of layoff

One dissection which could shed some light on the severity of intervention is days since a run, the theory being that the longer the layoff the more pronounced the procedure. There are, of course, many reasons for time off, notably the changing of the seasons and summer/winter breaks (the most obvious and opportune time to intervene in this way), but it is still worth reviewing the numbers.

In this case, I am interested specifically in W1, that first start after surgery, and how it compares with horses running off a similar layoff but without ever having had wind surgery.

Comparison of flat to NH, W0 to W1, by time off course, UK 19/1/18-18/11/18

Comparison of flat to NH, W0 to W1, by time off course, UK 19/1/18-18/11/18

The above, slightly confusing, table allows for comparisons between various things. The data are broken down by race code and length of time off, and includes only horses which are having their first run post-wind surgery (W1) or which have never had wind surgery (W0). As can be seen, there are some very small sample sizes here, so additional caution is advised.

Looking first at the 'Flat W0' group - horses running on the flat which have never had declared surgical intervention - we can see that horses returning to the track within two months of their last run (Flat W0 0-60) fare a lot better than flat runners laid off for longer. That is consistently true for both win and place, the win element reflected in a positive impact value of 1.06.

Comparisons with the flat W1 group are tenuous due to the tiny samples in that set but, for what it's worth, there does appear to be a contrast, especially in the 0-60 window. Horses returning to the track within 60 days after wind surgery on the flat have significantly lower win and place percentages. The flat W1 61-120 group offers mixed messages, but using the slightly larger body of place evidence suggests that these runners are also under-performing.

But look at the longer layoff W1 flat horses - those absent for four months or more - and you'll note that there are across the board improvements on their W0 counterparts, albeit that the 180+ place numbers are the same.

If any conclusions can be drawn from that, and I am unconvinced that they can at this stage, it might be that the impact of (presumed, based on length of absence) minor wind surgery on flat horses is somewhere between neutral and negative.

With National Hunt horses, where there has been no wind surgery, we can see that the longer the layoff the less likely a horse is to win: horses backing up a run within four months having an impact value of about 1.04, whereas those returning after four to six months off drop to an IV of 0.97, and those absent for six months-plus are at 0.9 in IV terms.

Compare that high to low trend line with the National Hunt W1 runners, and we get an interesting - if less clear - pattern. Like their flat counterparts, the W1 quick returners win less often than the W0 quick returners; but, thereafter, those returning after a breathing operation out-perform those that are not.

The sample sizes are small here, and I don't think there is any confident inference to be drawn.

Impact of wind surgery by race class

Is it possible that horses running in a given race class fare better than others? Could such action allow classier horses to prevail more often, or is it more likely to positively impact low grade animals? Or does race class have no bearing?


On very limited sample sizes, it seems that there is an uplift in impact value in the better races - Class 1 and 2 - and that, otherwise, impact in terms of IV is minimal. First time after wind surgery may be worth marking up in better races.

Impact of wind surgery by race distance

I wanted to look at whether the extent of the stamina test faced by a horse, as opposed to more of a speed test, would be material from a wind surgery perspective. In the below, I've grouped all runs post-intervention as W+, and compared it with the W0 control once more. I've also broken down by flat and National Hunt, flat W+ tables first.

Performance of "W+" horses on the flat, by race distance and race distance group, 19/1/18-18/11/18

Performance of "W+" horses on the flat, by race distance and race distance group, 19/1/18-18/11/18

This is a deeply inconclusive set of figures, the comparison with W0 runners bearing that out below. That said, it may be reasonable to argue that flat horses running beyond a mile derive more benefit from wind surgery than those racing at shorter distances.


Perhaps the NH perspective will shed a little more light:

Performance of W+ horses in National Hunt races, by distance

Performance of W+ horses in National Hunt races, by distance


That's more like it. The race distance Impact Value comparison between W+ and W0 horses articulates the point more succinctly.


The blue bars represent the performance of National Hunt runners whose wind has been declared as addressed at some point. They have a performance edge, in terms of Impact Value, at least up to about three and a quarter miles. After that, the data are as inconclusive as they are sparse.


Impact of wind surgery by trainer

Some trainers are keener on wind surgery than others, though that may be on the 'off chance' it might eke out an iota of improvement rather than based on a deep consideration of the particular horse. This table shows all subsequent runs by horses since they first had officially declared wind surgery (i.e. W+).

W+ performance by trainer, 20+ runs, sorted by Impact Value

W+ performance by trainer, 20+ runs, sorted by Impact Value


As can be seen, Nicky Henderson appears somewhat selective with his use of breathing intervention, thus far at least; whereas others, perhaps notably Dan Skelton, are more inclined to tweak. In Dan's defence, plenty of his horses have run multiple times - he'd be far more of a campaigner than Henderson for example - and, furthermore, the results Skelton has achieved from his wind op runners are excellent, particularly so given his is more than twice the next biggest sample size in the set.

Looking only at W1-W4, and 15+ runs to qualify a trainer into the table, gives us this:

Performance by trainer, 1st four runs after a wind op, 15+W1-4 runners only

Performance by trainer, 1st four runs after a wind op, 15+W1-4 runners only


These tables are presented 'as is', readers invited to consider their content for themselves.

Please keep in mind that the sample sizes are tiny and have every chance of not being replicated in the future. Nevertheless, they at least offer a flavour of which handlers (or their owners) might be keenest to explore the procedural route. Further, there may be a note of caution around trainers whose overall performance is significantly better than that of their runners in this context.



This article contains a lot of words, numbers, tables and charts but, ultimately, very few solid conclusions.

Perhaps the most reliable takeaway is that wind surgery appears to be more effective in the National Hunt sphere than on the flat, and that there may be an increase in performance from first to second, second to third, third to fourth, and fourth to fifth runs post-surgery over jumps. Maybe also that horses returning from a 60+ day layoff (and likely a more material intervention - let us hope we have more specific information with regards to the procedure undertaken in the near future, such that we don't have to guess on this) are more likely to benefit from the W1.

Again, these are not confident inferences from the data, nor are they a route to blind profit; which solitary data element is? The key here is to understand the general impact of a factor and to incorporate it into your betting.

Blindly backing W1 or W2 or W3 or W4 or W5 runners will send you skint as sure as night follows day; but knowing that in some circumstances those runners may be expected to demonstrate a small uplift on previous performance levels is a powerful insight which can contribute to improving your bottom line.

We are a mere ten months into this project - what has happened for years can be vaguely quantified now for the first time - and there remain insufficient data to take unequivocal positions; but some clear patterns are emerging. The savvy bettor will keep them in mind.

- Matt Bisogno


p.s. this article was researched using Geegeez Gold's Query Tool. It is available to Gold subscribers as a part of your existing subscription. Moreover, all users have access to extensive notation of wind surgery on our racecards. Here is an example of a horse having its fifth run post-wind surgery. To access racecards click here. To take a trial of Geegeez Gold, click here.

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7 replies
  1. 10 Things You Didn't Know about Geegeez Racecards
  2. jashmeade
    jashmeade says:

    Great write up, you have answered my question without doing the hard work thank you.

  3. Steve
    Steve says:

    An excellent article and, as stated, conclusions can be incorporated rather than relied upon. Two thoughts 1. Data set is ten months old. Do horses who had ws 11+ months ago need to have this officially declared and, if not, are pre declaration ws creeping into w0 subset? 2. Of interest is the early Class assessment. Is it plausible the better horses simply have a more comprehensive (and more expensive) procedure because it offers value (they can win more if the op is successful) whereas lower grade horse have their wind ‘tinkered with’ more in hope/as a last resort and is probably a very cheap option? If so, the merit of your early Class conclusion could be something of real value to monitor going forward. Again, top work

    • Matt Bisogno
      Matt Bisogno says:

      Hi Steve

      1. There is no public record of earlier wind ops for horses running prior to 19th January. It is very likely that some of the W0 brigade will have had wind surgery, but based on the overall data, I’d expect it to be in the 5% or less range.
      2. No, I don’t think so. Wind operations are inexpensive procedures (I know as an owner what they cost), and the difference between the dearest and cheapest would not be much in relation to training costs. It remains, in my view, a reasonable contention that the intervention considered the most appropriate, rather than the cheapest, is the route taken. Apart from anything else, even with the smallest tweak horses have time out from training, which costs money!


  4. Pete Marsh
    Pete Marsh says:

    Well done Matt I love research that is well written and well evidenced but accessible in terms of technical language and plain speech, as ever you strike that perfect balance between these elements. Excellent Article.

  5. om0202
    om0202 says:

    A lot of work Matt but as you say no easy way to profit. My own hunch is that most horses are just not very good and wind ops make no difference but a few are short runners who always run well but never quite finish off their races. If we can identify that sub-set of horses, we might find a profitable angle. I think there were a couple of high profile horses at the Cheltenham Festival a couple of years ago who won at big prices only for the trainers to come out and say they benefitted from recent undeclared wind ops.

    Mike O

  6. legsdiamond
    legsdiamond says:

    Great article as per Matt,is there a way we can use this gr8 info prior/after ws in form reading(moved up in distance maybe) obviously it cant be used in a system.i would love to see the one off winning prices

    • Matt Bisogno
      Matt Bisogno says:

      Thanks legs – as I say, I think the best way to use it at the moment is as an ‘uplift’. What I mean by that is that, if I was choosing between two horses with very similar profiles, I might slightly favour the W1, W2, W3, W4, W5 on the basis that the (skimpy) evidence to date suggests the Wn horse might just step forward a little.

      It’s the same in my mind as a jockey uplift – I wouldn’t bet a horse because of the jockey, but it might be the final determining factor between two very similar horse profiles.

      Hope that makes sense,

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