Breeding For Durability

Some thoughts on Twitter discourse about soundness in the breed

There has been a lot of talk on Twitter over the past few years about the weakening of the breed, how breeders are breeding for brilliance over durability, and how the emphasis on speed has led to a deterioration in stamina. The launch of the National Thoroughbred Alliance and the recent announcement of the Belmont Stakes being held at a mile and a quarter (to fit the layout of Saratoga) have brought these conversations back to the forefront, and I have a lot of thoughts on the matter I’d like to share.

It’s easy to say things like “X stallion shouldn’t be breeding because he had soundness issues/only raced Y times/etc.” and “his owners should just geld him rather than letting him have hundreds of foals with these same issues.” It’s easy to be frustrated that “the only thing that matters is getting a sales horse,” and complain that a one furlong breeze in March or April of a horse’s two-year-old season shouldn’t be the most important eighth of a mile in their entire career. And there are very valid concerns behind these sentiments, but I don’t find them to be particularly productive comments on their own. Telling people “don’t do that” doesn’t generally lead to a change in behavior. An alternative needs to be presented, and there needs to be a short-term reason for that alternative to be considered. Unfortunately, the long-term betterment of the breed doesn’t pay this month’s bills.

The average starts per runner in a year has dropped significantly in the last 70 years (2020 numbers affected by COVID cancellations)

The trend of a declining number of horses making a declining number of starts per season (and, as a result, a declining average field size) has been going on for decades. According to statistics by the Jockey Club, the annual foal crop has shrunk from 35,051 in 1992 to an estimated 17,300 in 2022. The average number of starts per horse has gone from 8.03 in 1992 to 6.01 in 2022, and even in 1992, there were concerns about the declining durability of the breed, as evidenced in this Sports Illustrated article (frankly, concerns about the declining durability of the breed are nearly as old as the breed itself - an 1877 edition of London’s Daily Telegraph could’ve been written in 2023 with a few minor changes: French horses are sounder and winning all of the top British classics because short handicaps and two-year-old races aren’t valued there, long gone are horses like The Doctor who raced and won for ten successive years, many young Thoroughbreds leave the track worn out and unsound, and so on).

But that Sports Illustrated article does bring up another issue that has been a very important topic of conversation this year: breakdowns. According to a study cited in that article, there were 840 fatal racing injuries in 1992 and a rate of 1.08% fatalities to races. In 2022, the Equine Injury Database showed 1.25 fatalities per 1000 starts. With 275,434 starts in 2022, that gives us about 344 fatalities in 36,300 races, which is .95% fatalities to races. Obviously, there is still plenty to be done, but progress has been made as an industry in making this sport safer for our equine and human athletes, and new innovations such as StrideSafe technology should continue to revolutionize the sport from a safety perspective.

I think it’s entirely possible that an increase in safety precautions and stricter, more sensitive medication rules in recent years are as much a factor in the decrease in average starts per horse as breeding or training practices. It’s surprising to me how infrequently this comes up in discussions of soundness and durability, and I think there’s a very good chance that this is simply a tradeoff that the industry has to accept, at least to a certain degree. Are horses that significantly less sound nowadays, or are we not pushing them as hard?

Another point that has been raised by others but seems pertinent to make here is that trainer stats, such as win percentage, have not always been public knowledge. The first year that the Daily Racing Form published trainer statistics for the Breeders’ Cup card was 1993, and they didn’t add year-to-date statistics until 1996. Prior to that, a savvy handicapper would have to keep their own statistics if they wanted to know a trainer’s percentage of winners. While the number of winners and earnings by a trainer in a season were tracked going back until at least 1908, it wasn’t until the early to mid ‘90s that a trainer’s win percentage became key to attracting owners.

Nowadays, the practice of “racing into shape” is largely nonexistent, largely in order to maintain those high win percentages. Anyone who was on Twitter when it was announced that Mage would be using the Haskell as a prep for the Travers might have an idea of another reason why trainers aren’t particularly keen on those kind of moves in the modern era. Again, are horses that much more unsound, or are trainers taking their time and opting to train up to their biggest efforts rather than risk a loss?

Track surfaces are also a potential factor in this phenomenon, although one that is hard to quantify. The final times of elite races has become increasingly faster over time, particularly from the mid-19th century to around 1950, with the rate of improvement slowing (although not stopping) around that time. The record for the fastest times in the U.S. Triple Crown races has been held since 1973. I’ve been told that tracks used to be deeper, slower surfaces, which perhaps led to horses being able to race more frequently over them. A 1911 edition of the Lima Morning Star and Republican Gazette mentions tracks being made harder in America in order to record faster times, and proclaims that “a great many, perhaps the majority, of racehorses in the United States are unsound.” Once more, is unsoundness in the breed a phenomenon that has emerged in the last fifty years or so, or something that is much deeper-rooted and being exacerbated by modern practices?

Also, due to some of the factors I mentioned above, I want to be clear that I do not think that number of starts in a season or career is even necessarily a great measure of soundness, particularly when comparing against horses from different eras - it’s just all we have to work with as an objective measure. Anyone with some knowledge of racing history has heard about horses racing with patched-up injuries that would result in a scratch in today’s world. Buckpasser missed the Triple Crown of 1966 with an infected quarter crack, but still made 12 starts that season. He raced “only” six times in 1967 due to the same issue, and came out of his final start with heat in his right front foot - the same foot that had troubled him all summer. Is it correct to infer that Buckpasser was more structurally sound than modern horses, despite having very well-documented foot issues? Perhaps that’s the case, but I’m uncertain. He made 31 starts in three seasons, which is unheard of for a horse of his caliber today. However, I think there’s a distinct possibility that Buckpasser possessed a similar constitution to many modern horses, but the techniques for dealing with that constitution and his own superiority as a racehorse allowed for him to compete as frequently as he did even with nagging quarter cracks.

Having said all of that, I obviously want to see the current trends of horses making fewer starts reversed, so let’s dive a bit deeper into some of the explicit concerns I’ve seen expressed on social media, and then I’ll give some of my ideas for improving the soundness and durability of the breed, specifically focusing on the goal of having horses make more starts in a season, as that is the most easily tracked metric.

Lightly Raced Horses at Stud

One topic that has gotten a lot of buzz this year is the fact that horses are retiring to stud after 10 or fewer lifetime starts. Clearly, there is zero chance of any kind of mandate prohibiting horses from retiring to stud without a certain number of starts, but would that help with soundness in the breed?

Forte’s retirement was met with plenty of outcry on social media. The horse had been scratched from the Kentucky Derby after battling a quarter crack in the lead up to the race, and had only started ten times in his career. How does Forte’s retirement differ from Buckpasser’s, from a genetic standpoint? If Forte had been given time off and come back as a four-year-old, would that have made him any more fit to breed in 2025? Of course not. The only difference is the money invested in the horse and the risk of greater injury before he could begin his stud career. As much as I would have loved to see what Forte could accomplish on the track as a four-year-old, the retirement made sense.

Big Brown is a leading sire by durability measures despite struggling with quarter cracks in his career. Photo by Barbara Livingston

Big Brown famously struggled with quarter cracks throughout his career, retiring after just eight starts, and yet he ranks 33rd by lifetime starts per starter and 31st by percentage of starters from foals of racing age on the Grayson-Jockey Club’s durability report, which considers the top 200 leading stallions by progeny earnings in 2022. Big Brown’s foals, on average, make over twice as many starts as their sire. By comparison, Star Guitar, who started 30 times in his career, ranks 60th by starts per starter and 100th by percentage of starters from foals.

Of course, this is just one example, and many of the top-ranked sires on the durability list had lengthy careers themselves, but I think it’s illustrative of the fact that there are many elements that go into how many starts a horse makes in their career, and only breeding stallions who make a certain number of starts is not only an unreasonable expectation of owners and breeders, but it’s not guaranteed to increase durability in the breed.

Historically, there are plenty of stallions who Twitter would've been infuriated to see retire to stud, yet still produced runners with a number of career starts at the highest level that you just don't see nowadays. Bull Dog raced 8 times before being purchased for stud duty in 1930 after his full brother had sired Triple Crown winner Gallant Fox. This wasn’t necessarily due to unsoundness, but because Bull Dog was more valuable as a stallion than he was as a racehorse, where he’d found only moderate success - the phenomenon of horses being more valuable in the breeding shed than the racetrack is certainly more common nowadays, but it isn’t a new development in the breed. As a sire, Bull Dog produced the likes of Bull Lea (27 starts), Occupation (32 starts), and Bull Reigh (115 starts), among others.

How about Blandford, retired after four starts with bowed tendons in both forelegs, but the sire of four Epsom Derby winners between 1929 and 1935, though notably none of them had particularly long careers, themselves - again, the phenomenon of brilliant but fragile horses going on to be successful stallions is not particularly novel. The issue, again, is the frequency that it occurs in the modern era, and the lack of sounder blood to balance it: Blandford was also the sire of multiple stakes winner Isolater, who raced 52 times to the age of seven but was out of a daughter of Kentucky Derby winner Omar Khayyam. That stallion raced 28 times and was the sire of horses such as Malicious, who raced from ages two to thirteen and won 32 of his 185 starts. His best distance was two miles, but he raced at distances up to four miles. Extreme distances aside, this kind of balancing of brilliance over durability and stamina is hard to do with modern bloodlines.

The median number of starts for the 88 stallions profiled in the 1977 edition of the BloodHorse’s Sire Lines (stallions born between 1900 and 1957) was 16, while the median number of starts for the 88 leading sires by earnings of 2023 is 11. This appears to be a measure that’s going down a bit slower than the average number of starts per horse per year, at least going back to 1950, the earliest year the Jockey Club Fact Book has on record. The number of starts per year per horse has decreased by 45% from 1950 to 2022, from roughly 11 to 6. The difference in the number of average lifetime starts per stallion from the Sire Lines era to the top 88 stallions of today is 31%. The average stallion still has to prove himself on the racetrack relative to the general population - stallions retiring to stud in Kentucky in 2024 raced an average of 13.4 times and median of 12 times in their career (these numbers increase to 16.2 and 13.5 if you include regional stallions).

This is not a new trend, clearly, but it is a worsening one. However, I don’t think it’s something that is readily reversed. It just doesn't make sense economically to keep a fantastic stallion prospect racing after a certain point in their career. I think this phenomenon is a symptom of a much larger set of issues, and I don’t think that forcing stallions to make a certain number of starts before standing at stud (a proposal I’ve seen tossed around online) would do much to help improve soundness in the breed even if such a rule were possible to enact. It wouldn’t take unsound horses out of the breeding pool, it would just delay their introduction to it. If we want to breed horses who can race more often, we have to make do with the current status quo in the stallion market.

So What About Mares?

The idea of crossing brilliant sires over stouter mares (and the reverse) is age-old, and I think it’s an interesting thought experiment to imagine what that might look like in modern times, because trying to convince owners to race valuable stallion prospects after a certain point seems like a losing battle.

The Grayson-Jockey Club’s stallion statistics are a valuable resource for owners and breeders focusing on durability and soundness

The Grayson-Jockey Club publishes a fantastic yearly resource of stallion statistics on durability and soundness, which I highly recommend for breeders looking to infuse more durability into their stock. Maybe the key is to go buy up some of the better Windsor Castle mares from Charles Town - his starters average 22 career starts. His daughters get 68% winners and 2% SWs, with an AEI of .73. Maybe a good stallion could move that up?

From this perspective, there are actually quite a few intriguing broodmare sires in the Mid-Atlantic. Weigelia's daughters have gotten 11 winners and a stakes winner in 13 starters and an AEI of 1.21. He's inbred 3x3 to Northern Dancer, who gets a lot of fingers pointed his way as a source of unsoundness in the breed. Yet, I think that Kentucky breeders looking for a little extra soundness could do no better than introducing classy daughters of Weigelia to their broodmare bands.

Include, who ranks seventh by average starts per starter in 2022, is a very solid broodmare sire: his daughters get 71% starters, 65% winners from starters and 4% SW. Proxy retires to stud in 2024 and is out of a mare by Include, and while he had an abbreviated three-year-old season, he raced consistently at ages four and five.

City Zip gets an average of over 19 starts per starter, and his daughters produce 70% starters, 66.7% winners, 4% stakes winners, and an AEI of 1.08. He’s the sire of two Kentucky stallions, Collected and Improbable, who each made 15 starts in their careers. Collected has proven to be a useful stallion in his first two crops, so perhaps he and Improbable can carry on the durability of the City Zip line.

Brothers Congrats and Flatter are sons of A.P. Indy who both get an above-average number of starts per starter. As broodmare sires, Congrats gets 69% starters, 61% winners, 4% SWs, and an AEI of 1.19. Flatter's daughters get 69% starters, 66% winners, 6% SWs, and an AEI of 1.19.

Flatter is the broodmare sire of Taiba, whose first three dams averaged 31.3 starts each and whose sire Gun Runner raced 19 times. Yet, despite being bred for soundness, Taiba raced only 8 times. Perhaps his pedigree wasn't the only factor in determining how many starts he made? Taiba is also a great example of getting a highly commercial horse from a state-bred mare who was among the best in her Ohio-bred division at two, three, and four. I think mares like Needmore Flattery could be instrumental in getting top-class racehorses who are commercially viable and also sound enough to race more frequently than four or five times a year, although there is a theory that has been held by such brilliant minds as Federico Tesio stating that a mare can be over-raced and her production negatively affected. I haven’t been able to find any research on the matter, but it’s a theory that could be worth examining further.

I think there are solid broodmare sire options for breeders who wish to go the “brilliance over stoutness” route, and there are recent examples of this pattern getting a horse that is both high quality and commercial, which brings me to my next topic: sales.

Breeding for the Sales Ring

I and many others have long bemoaned the fact that the commercial market plays a huge role in planning matings - even in the aforementioned 1992 Sports Illustrated article, the rise of the sales industry was cited as a source of unsoundness in the breed, as breeders needed to breed for a pedigree page and didn’t have to worry about whether the horse could stand up to training and racing. Unfortunately, like most of these issues, the trend of breeding to sell isn’t something that is readily changed.

Of the 10 stallions with foals of racing age who had a yearling sell for at least $1,000,000 in 2023, only two (Curlin and Twirling Candy) met or exceeded the Grayson-Jockey Club’s breed average of 14.1 starts per starter for foals by the top 1% of stallions, and only two others (Into Mischief and Tapit) met or exceeded the breed average of 77.85% starters from foals for the top 1% of stallions. Half of the 12 stallions with seven figure yearlings in 2023 had fewer than ten starts. So there does appear to be a tendency for brilliance to outsell soundness, but what can the industry do to combat that when brilliance is what sells?

With foal crops steadily declining, the last thing the sport needs is to discourage breeders from breeding horses, and for many breeders, being able to sell their youngstock is the only way to ensure their operation is sustainable. Whether we like it or not, the commercial market is going to continue to drive a large percentage of breeding decisions, especially at the highest levels of the sport. So, is there a way to encourage buyers to factor durability more heavily into their considerations? I think there is.

Though often criticized for incentivizing the prioritization of brilliance over durability, the sales ring keeps many breeders afloat.

Ideas and Solutions

The commercial market relies heavily on nick ratings such as TrueNicks to determine the appeal of a particular mating. What if there were a similarly easy-to-digest rating for soundness, something like a durability index? Even better, what if horses above a certain durability index rating were eligible for purse bonuses? What if, similar to something like the Virginia-Certified program, there was a set amount of money to be dispersed to horses who were certified by this durability index to be bred to a certain “breed improvement” standard that factored in things like the class, number of lifetime starts by the sire and dam, and the performance of their offspring by metrics such as percentage of starters and number of starts?

In my vision of this hypothetical program, the breeder pays a small fee to certify the horse, which is then given a letter grade (or perhaps a simple pass/fail rating) based on a standard that remains dynamic and is reviewed on a regular basis. This certification could be printed on a catalog page alongside other incentive programs the horse is eligible for, and horses could earn a small bonus on purses throughout their career, likely a percentage of an allocated yearly budget. This is an idea I’ve been tossing around in my head for a few years, and I’d love some feedback on why it wouldn’t work or suggestions on how to go about making it a reality. “Breed sounder horses” is a noble but ultimately vague goal; without quantifiable measures of what that means, evidence of how to do so without sacrificing quality, and incentives for the commercial breeder, it’s a hollow call to action.

Another avenue the sport could explore is to find ways to incentivize owners - especially smaller-scale ones - who race homebreds. I’m a big fan of the recent auction price restricted race conditions, and would be curious whether races could be filled based on a condition for horses who were bred by their current owner. An additional condition based on stud fee might also be appropriate to prevent those purses being swept up by the larger farms whose horses will be plenty competitive in open maiden special weight company. Of course, as I alluded to, I’m not sure that there are enough horses at any given track to fill, say, a maiden special weight for homebreds by stallions who stand for $10,000 or less. At that point, you may just be taking away from races like state bred restricted maiden special weights. It’s not a perfect concept, but there are clever, innovative people in our sport who I believe could fine tune it.

Another conversation topic, and one that could be an entire post on its own (I’ll let Jay Hovdey’s piece speak here to avoid taking up more of your time) is the absurdity of the graded stakes system in this country. Maybe if a horse couldn’t be a G1 winner by September of their two-year-old year or April of their three-year-old year, there would be an incentive to race longer and/or more frequently. Why bother to take the time with your Florida Derby winner to come back for a four-year-old campaign when he’s already got that coveted G1 win he needs for a stallion career?

Incentives for horses who start a certain number of times in a year or in their career could be interesting, but - similar to paying out purses through last place - could possibly raise the risk of a horse being pushed too hard to simply pick up an extra check for their connections.

Even the valuable Grayson-Jockey Club durability list has its shortcomings, as the document itself mentions. A quick glance at the top stallions by number of starts per foal makes one of these pretty obvious - many of the highest-ranking stallions by this measure are regional sires, whose offspring are not racing at the highest level and thus are not retiring early as breeding stock. If you have a son of Windsor Castle racing in West Virginia, even a stakes-winning one, you’re likely not planning on a stud career for that horse and will race him until he’s much older than you would race an equally talented son of Into Mischief (who was still in the top 100 of the 200 leading stallions on the most recent list, with 12.8 average starts per starter). The same goes for percentage of starters - if you have a well-bred but slow daughter of War Front (who is still a top 50 stallion by that metric), you might opt to breed her without risking losing her in the claiming ranks where she’d be competitive. The same can’t be said for a slow daughter of Court Vision.

One thought this brings to mind, and a point that was raised at the recent University of Arizona Racetrack Industry Program Global Symposium on Racing, is that perhaps abolishing or reworking the claiming system could incentivize horses to race more often. If you don’t have to worry about losing your slow but well-bred filly to a claim, maybe you’ll be more likely to give her a chance to prove herself on the racetrack rather than immediately retiring her. If you have a hard-knocking gelding, maybe being able to run in a protected spot gives you the confidence to take a little shot in a tougher spot rather than waiting for the perfect race where you can make the most on your investment before he gets claimed away.

Conclusion

This is all a long-winded way of saying that I think the outcry on social media toward modern breeders as the source of unsoundness in the breed is just the latest refrain of an age-old song, one that is a product of the very foundations of the breed, and one that isn’t going to be solved in a couple of generations. Breeders and sales companies aren’t the sworn enemy of full fields and sound racehorses, and any solution to the problem needs to align with their interests to have any chance of success due to the structure of the sport today. Incentives such as purse bonuses and making durability a metric that can be ascertained at a glance could help durability be a greater factor in the decisions of buyers and, as a result, breeders. The industry could also work on finding ways to make breeding to race a smart economic decision. Making it harder for a horse to get graded black type, especially G1 wins, could incentivize top-level horses to stick around and race more often instead of being whisked off to the breeding shed after minor setbacks, and restructuring of the claiming game could encourage the connections of lower-level horses to race more frequently.

It’s unlikely that we’ll ever return to the days of horses regularly running back on a week of rest or top-class horses running a dozen or more times in a season, and that’s something we likely need to accept in exchange for the recent innovations in safety. We’re probably not going to see dramatic improvements over the next few years, but we can aim for the same kind of gradual but steady improvements in field sizes and starts per season that we see in the fatality rates over the last 15 years.

I wanted to bring some historical context to the current situation and offer some ideas for changes that I find more reasonable than many vague and/or impossible solutions I’ve seen proposed online. It’s my hope that industry stakeholders will be able to work together and find solutions that are in the best interests of the humans and horses involved in the sport we all love.