At the risk of getting flamed by everyone on this board, I'd like to open up a discussion/evaluation of the X factor theory as presented by Marianna Haun.
This issue seems to have polarized the folks that participate to a high degree, with some folks believing the whole idea is crap, while others give the theory credence. This board is visited by folks with a huge amount of experience, and it would be great to have a open non-partisan discussion on this theory. And that includes the X-factor is crap crowd.
Warning, this is a long post, and covers a lot of ground.
Overview
The X-factor as proposed by Marianna Haun is that large hearts in TB's is caused by a gene, or gene complex, is sex linked and large hearts are linked to superior performance in TB's.
Summary of the X factor books.
Marianna Huan's first book "The X factor: What it is and how to find it" was published in 1997, and "Understanding the power of the X-factor" was published in 2001.
The two books go into lots of detail, citing genetic research mostly done in Australia, linking the large heart to increased performance, and tracing the large heart gene to the X chromosome. The second book includes lots of photos of horses, their EKG tracings, and further theories including the idea that the structure of the forehand of the horse is determined by the X chromosome and that shape of the ear can be used as a X chromosome marker.
The Spin
The spin in the two books is easy to spot, the books are a seductive blend of genetic science and appeal to the underdog. The "Cult of the Stallion" and mainstream big breeding operations take their share of lumps. She presents the idea that if you just read her books accept her theories, success in breeding TB's will be yours, and like a Hollywood movie, you will end up in the winners circle with a Triple Crown winner. She seems to have a firm grasp of the idea that the TB industry is about selling dreams. And her publishers have an even firmer grasp on the idea that folks will buy books on how to win at the racing/breeding game.
There are a couple of very good reasons the books might have this particular spin. In no particular order:
dreams sell better than reality, and a book titled "Dud Studs and how to avoid them" has a smaller market than the X factor titles.
She's a fan of Secretariat, and brings that mind set to her research and writing, and she needed to have access to some very famous valuable stallions. Imagine trying to gain access for testing to the manager of a big name stud. Big farm manager is more likely to agree to have his stallion tested for a book extolling the virtues of the large heart than a book about "Dud Studs" with his horse in a starring role.
A major character in the books is the largest of the large heart stallions, Secretariat. Marianna Haun was a Secretariat fan from his racing days, and uses Secretariat and his racing career, his offspring, and is heart scores to illustrate parts of her theory. She turns Secretariat into the poster boy for the X-factor, and makes the claim that he was not a failure at stud, he was mis-understood, mis-managed, and will be vindicated as his daughters pass their large hearts on to the next generation.
All that you need to do to have a stakes winner is to breed for the X factor, wait till the correct X shows up, and fame and fortune will follow. The breeding strategy can best be summed up by "Breed any horse to a double copy X factor mare, and fame and fortune will follow"
The spin may be the most irritating part of the theory, especially to people who have a great deal of knowledge about TB bloodlines.
Spin vs. Reality
Here's a quick real world test of the X-factor Theory.
Let's suppose that by now Secretariat daughters have produced 1000 foals. According to the theory, all of his daughters will carry the Secretariat large X, and about half of the foals will have the large X. 500 large heart foals, 500 regular heart foals. From a population of 500 large heart foals, half should be colts or about 250. According to the X factor books, this group of 250 colts should have had stellar racing careers, and been retired to stud to pass their large hearts on to the next generation.
To date: Storm Cat, A.P. Indy, Gone West and who else? There sure don't seem to be hundreds of Secretariat maternal grandsons with great race records standing at stud. Why are the number so far off?
Back to the science behind the X factor for another take on what may be happening.
According to the Australian study, performance of a horse may be affected by up to 23% by the presence of the large heart.
So the advantage of having a large heart comes on top of all the other elements that make up a TB racehorse. Having a large heart will increase the duration a horse can maintain their top sprinting speed, not change what the top sprinting speed is.
In other words, it acts like a turbo charger on the basic horse, and will enable an already fast horse to run fast longer, it does not make a slow horse run fast, it just allows a slow horse to run slow longer.
Here's a simplified way to look at the TB gene pool in terms of US flat racing, apologies to international board members, and US Sport horse folks,
Normal heart horses can be divided into the following 25 categories, which can easily be expanded to 100%. Adding 4 horse per category will add up to 100. But doesn't reflect the actual distribution. A better model would be in the shape of a pyramid, with one horse per G1 category, 2 in the G2 category, 3 in the G3, and the rest spread out between the last two groups. ( Or any other distribution pattern that you think best reflects the gene pool, as long as there are fewer horses in the G1 group, and more in the Also Rans.
Sprinter G1 Miler G1 Classic G1 Stayer G1 Plodder G1
Sprinter G2 Miler G2 Classic G2 Stayer G2 Plodder G2
Sprinter G3 Miler G3 Classic G3 Stayer G3 Plodder G3
Sprinter Claimer Miler Claimer Classic Claimer Stayer Claimer Plodder Claimer
Sprinter AlsoRan Miler AlsoRan Classic AlsoRan Stayer AlsoRan Plodder AlsoRan
Add the large heart and increased cardio to the same group of horses, and here's the results.
A large heart AlsoRan, remains a AlsoRan.
A large heart Plodder, now can plod home at much longer distances, but still is not fast enough to win most flat races in the US.
A large heart Stayer, may now be able to be fast enough to win at longer distance, so there would be some effect, it might also change a Stayer Claimer to a G3, G2 to a G1.
A large heart Classic Horse -The G1 now becomes a super horse. It might change a Claimer to a G3, G2 to a G1.
A large heart Miler, now is able to compete at classic distances. It might change a Miler to a G3, G2 to a G1.
A large heart Sprinter is now able to get distances up to a mile. It might change a Sprinter to a G3, G2 to a G1.
The greatest effect can be seen in nine categories:
Sprinter G1 Miler G1 Classic G1
Sprinter G2 Miler G2 Classic G2
Sprinter G3 Miler G3 Classic G3
Now take our hypothetical 250 Secretariat maternal grandsons, and spread them evenly over the 25 categories. There would be 3% G1 winners, 6% G2 winners and 9% G3 winners. These numbers are a whole lot closer to the observed reality.
Before the flames start, this is a model. It is intended to be a very simplified model of a incredibly complicated real world dynamic and ever changing biological system. This is only one way to view the gene pool, if you have a different view I'd love to hear about your version.
Dud Studs.
Without getting into the debate of how the large heart gene is transmitted, most people will agree that there is some method of passing the gene into the next generation, and it is not as simple as a single dominant gene. And it is pretty clear that a stallion does not pass his heart directly to his sons.
The goal with selective breeding is to maximize the number of horses in the G1 categories, breeders work very hard to match performance, pedigree, conformation to create their vision of the perfect horse.
With a normal heart stallion, his genotype (what he can pass on to the next generation) is reflected in his phenotype (the genes that are expressed and we see) This enables breeders to accurately judge the qualities they are breeding to.
A large heart stallion has a deceptive phenotype--it is enhanced from what his genotype is going to pass on to the next generation. A large heart miler is going to breed like a sprinter. Or a Grade 2 sprinter will breed like a claimer. The large heart stallion has two major problems, one he doesn't pass the large heart to his sons, and two, he is likely to get the wrong type of mares because breeders look at the phenotype, and can't see the underlying genotype.
The best breeding prospect may be a stallion with a good race record and a small heart. In this case in order to compete successfully his phenotype must be phenomenal. He won't pass his small heart on to his sons, who will have normal, or large hearts.
In short, a large heart is great in a racehorse, and a chancy thing to have in a breeding stallion.
Given that this is a long post, how the large heart is inherited is going to have to wait for another day.[b][/b]
X-Factor Dissected
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Interesting post. My own opinion, for what it is worth, is that a large heart is only one factor in trying to build a superior racehorse: you also need balance, athleticism, and enough mental and physical soundness to withstand the rigors of racing. Funny, though; your post seems to stand what I'd heard before, that the large heart benefits staying types more, on its head.
By the way, I think Bold Ruler only had an average-sized heart. Anyone know about Northern Dancer?
By the way, I think Bold Ruler only had an average-sized heart. Anyone know about Northern Dancer?
"A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher...You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse." C. S. Lewis
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Haun places Northern Dancer in the Mamhoud heartline.
[quote]My own opinion, for what it is worth, is that a large heart is only one factor in trying to
build a superior racehorse: you also need balance, athleticism, and enough mental and physical
soundness to withstand the rigors of racing. [/quote]
Right on. The large heart is only one factor in creating a superior racehorse, and is probably less critical than good legs, sound feet, and the rest of the physical package.
If a horse can't run a quarter in time faster than .26 downhill with a tailwind, doesn't matter what the size of the heart is.
This doesn't mean that the horse is useless, and depending on other factors might make a superior event horse, or hunter, or any other career that doesn't depend on sheer speed.
The trick is knowing what you are breeding to, so as to minimize expensive surprises.
[quote]My own opinion, for what it is worth, is that a large heart is only one factor in trying to
build a superior racehorse: you also need balance, athleticism, and enough mental and physical
soundness to withstand the rigors of racing. [/quote]
Right on. The large heart is only one factor in creating a superior racehorse, and is probably less critical than good legs, sound feet, and the rest of the physical package.
If a horse can't run a quarter in time faster than .26 downhill with a tailwind, doesn't matter what the size of the heart is.
This doesn't mean that the horse is useless, and depending on other factors might make a superior event horse, or hunter, or any other career that doesn't depend on sheer speed.
The trick is knowing what you are breeding to, so as to minimize expensive surprises.
OK I might be totally off base here... but in people an "enlarged heart" (medically different from a large heart) is a BAD BAD BAD thing. How do they differentiate between an enlarged heart and a genetically normally large heart based on measurement of the heart at autopsy?
Of course this is just sort of a vague idea.. but the enlarged heart is also genetic in people, as goes the theory of large heart in TBs. Is it possible that the heart is normal early in life and enlarges with the stress of breeding etc? Blasphemous, I know lol.
We had a vet one time that had me listen to a heart murmur in a horse - told me that a high % of racehorses have asymptomatic heart murmurs. However, arrhythmia (sp?) is also a symptom of an enlarged heart I believe. Must do more research...... some time. Just a thought to throw into the mix.
http://www.jhbmc.jhu.edu/healthcarenews/01080102.html
http://www.doctorshospital.org/healthre ... egory=5545
Of course this is just sort of a vague idea.. but the enlarged heart is also genetic in people, as goes the theory of large heart in TBs. Is it possible that the heart is normal early in life and enlarges with the stress of breeding etc? Blasphemous, I know lol.
We had a vet one time that had me listen to a heart murmur in a horse - told me that a high % of racehorses have asymptomatic heart murmurs. However, arrhythmia (sp?) is also a symptom of an enlarged heart I believe. Must do more research...... some time. Just a thought to throw into the mix.
http://www.jhbmc.jhu.edu/healthcarenews/01080102.html
http://www.doctorshospital.org/healthre ... egory=5545
Very interesting theory, x factor. It seems to answer many of the questions I have about x factor genetics, but I also agree that the large heart is just one peice of a very complicated genetic jigsaw puzzle that is a great racehorse. There are probably too many considerations to possibly grasp when it comes to the planning the perfect hypo-mating, and maybe that's why so often the great ones are simply produced by chance, not design.
So many pedigrees...so little time. (C)
"Overview
The X-factor as proposed by Marianna Haun is that large hearts in TB's is caused by a gene, or gene complex, is sex linked and large hearts are linked to superior performance in TB's. "
From what I have read recently, this linkage is nebulous, at best. Recent autopsies on several very good racehorses revealed that their hearts were only average sized, and one was below average. I assume that the better racehorses are more likely to be autopsied than the cheaper ones; if that is true, then how are we to know that cheaper racehorses don't have just as many large hearts as good ones?
The X-factor as proposed by Marianna Haun is that large hearts in TB's is caused by a gene, or gene complex, is sex linked and large hearts are linked to superior performance in TB's. "
From what I have read recently, this linkage is nebulous, at best. Recent autopsies on several very good racehorses revealed that their hearts were only average sized, and one was below average. I assume that the better racehorses are more likely to be autopsied than the cheaper ones; if that is true, then how are we to know that cheaper racehorses don't have just as many large hearts as good ones?
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You too are both correct, the X factor is only one part of a very complex puzzle.
A large heart in a plodder is nice, but doesn't win races. Ditto any horse with major conformation problems, neuro-muscular problems, horses that don't like to race, are just plain crazy, or simply to slow to win in any company.
The flip side of this is that if you breed are good horse increased cardio funciton sure won't hurt.
In her second X-factor book Haun talks about her breeding program, and the offspring of her double copy mare. None of her X-factor horses made any sort of impact on the track.
Or at least they hadn't last time I looked them up on the database.
The rah-rah spin on the x-factor seems to have done a huge amount of damage to the credibility of the real science that Haun observed and reported on.
Breeders who have been working with TB's for years know that a great TB is not as simple as waiting for one gene to show up in the correct place.
For a breeder, the best choice of sires may be the small heart stallion with a good race record. This horse is going to have smaller cardio function than the horses he's racing against, so everything else has to be superior.
I've heard that Caro has a smaller than normal heart, Bold Ruler had a normal heart as did Mr. Prospector.
Anyone have heart scores/weights from other stallions?
A large heart in a plodder is nice, but doesn't win races. Ditto any horse with major conformation problems, neuro-muscular problems, horses that don't like to race, are just plain crazy, or simply to slow to win in any company.
The flip side of this is that if you breed are good horse increased cardio funciton sure won't hurt.
In her second X-factor book Haun talks about her breeding program, and the offspring of her double copy mare. None of her X-factor horses made any sort of impact on the track.
Or at least they hadn't last time I looked them up on the database.
The rah-rah spin on the x-factor seems to have done a huge amount of damage to the credibility of the real science that Haun observed and reported on.
Breeders who have been working with TB's for years know that a great TB is not as simple as waiting for one gene to show up in the correct place.
For a breeder, the best choice of sires may be the small heart stallion with a good race record. This horse is going to have smaller cardio function than the horses he's racing against, so everything else has to be superior.
I've heard that Caro has a smaller than normal heart, Bold Ruler had a normal heart as did Mr. Prospector.
Anyone have heart scores/weights from other stallions?
I'm curious about Conquistador Cielo and Danzig. Is there any data on their heart size?
So to recap, this theory is suggesting that breeding a stallion with a superior race record but only a normal heart size to a mare who may carry x factor could result in one of these "supercharged" individuals?
So to recap, this theory is suggesting that breeding a stallion with a superior race record but only a normal heart size to a mare who may carry x factor could result in one of these "supercharged" individuals?
So many pedigrees...so little time. (C)
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More or less.
However the part that is glossed over in both of the X-Factor books is that you have to have a good racehorse to begin with for the X-factor to have any effect.
So a good normal heart stallion, and a less than stellar x-factor mare is going to have the same chance of success as breeding a normal heart stallion to a less than stellar normal heart mare.
However the part that is glossed over in both of the X-Factor books is that you have to have a good racehorse to begin with for the X-factor to have any effect.
So a good normal heart stallion, and a less than stellar x-factor mare is going to have the same chance of success as breeding a normal heart stallion to a less than stellar normal heart mare.
I read the book... Haun doesn't help her theory by repeating it over and over... nor does the lack of success of her own breeding program (as detailed on the web site she had/has) -- the problem with all theories of thoroughbred breeding is that it takes a long time to prove them, and she published first, and those who embraced the concept are the guineapigs.
But her book certainly made me look for more information on the biomechanics of the racehorse, and there are companies who measure key traits (cardiovascular and pulmonary) and have tried to market the data they gather to trainers and to breeders. It's a tough sell. The fact is that those who are heavily invested in the existing methodology resist any alternative way of evaluating a horse because the fear their investment will lose because of it (as in the original post - who wants to hear their horse is a "dud stud") or that they will be out of a job. This is completely normal to all social/business institutions.
Think back to the advent of the internet - I worked at a large financial institution, and I can't tell you how many of its high-level executives told me that it would all be over in a year,whilst they were quaking in their boots, worried that their brokers would rise up en masse if they had on-line trading on their web site, but terrified that if they didn't do it, the E-trades of the world would steal all their business. They ultimately bought an on-line trading company and over the course of a year changed its name and branding until it is now integrated into the company. They still have an army of brokers as well, who of course were selling internet stocks like mad, and now the same executives are hoping to avoid prosecution for overhyping them...
That was all a lot more dramatic than the way the X-factor theory has been criticised and embraced, but I think there will be a cycle of change in the thoroughbred industry as more "scientific" theories are developed based on the first glimmers of knowledge we have about the genome and transmission are published, overhyped, brought into perspective and ultimately incorporated into or rejected from our body of "common sense" knowledge.
I myself was intrigued by an earlier thread where someone (I am sorry, I forget who) said that the front end of a horse is usually more influenced by the sire, and the hind end by the mare - oversimplified? - I went back and looked at a picture of Williamstown, whose sire is Seattle Slew, and whoses dam has no picture, but whose sire is Northfields, who is also pictured here. Lo and behold, he has Seattle Slew's shoulder, and Northfield's hind end. So I consider this theory not proved, on the basis of one horse, and one set of pictures, but intriguing, nonetheless. It would suggest some truth to what I have bee told - that Raise a Native foreleg issues are more troubling in the tail male line than when he appears on the dam's side. Hopefully someone will research this in depth.
PS: Jessi, on your question of whether a "large" heart is engorged, as with a "large heart" in humans - Haun differentliates between a heart that is large because it is functioning improperly and one that is large in the sense of increased capacity.
But her book certainly made me look for more information on the biomechanics of the racehorse, and there are companies who measure key traits (cardiovascular and pulmonary) and have tried to market the data they gather to trainers and to breeders. It's a tough sell. The fact is that those who are heavily invested in the existing methodology resist any alternative way of evaluating a horse because the fear their investment will lose because of it (as in the original post - who wants to hear their horse is a "dud stud") or that they will be out of a job. This is completely normal to all social/business institutions.
Think back to the advent of the internet - I worked at a large financial institution, and I can't tell you how many of its high-level executives told me that it would all be over in a year,whilst they were quaking in their boots, worried that their brokers would rise up en masse if they had on-line trading on their web site, but terrified that if they didn't do it, the E-trades of the world would steal all their business. They ultimately bought an on-line trading company and over the course of a year changed its name and branding until it is now integrated into the company. They still have an army of brokers as well, who of course were selling internet stocks like mad, and now the same executives are hoping to avoid prosecution for overhyping them...
That was all a lot more dramatic than the way the X-factor theory has been criticised and embraced, but I think there will be a cycle of change in the thoroughbred industry as more "scientific" theories are developed based on the first glimmers of knowledge we have about the genome and transmission are published, overhyped, brought into perspective and ultimately incorporated into or rejected from our body of "common sense" knowledge.
I myself was intrigued by an earlier thread where someone (I am sorry, I forget who) said that the front end of a horse is usually more influenced by the sire, and the hind end by the mare - oversimplified? - I went back and looked at a picture of Williamstown, whose sire is Seattle Slew, and whoses dam has no picture, but whose sire is Northfields, who is also pictured here. Lo and behold, he has Seattle Slew's shoulder, and Northfield's hind end. So I consider this theory not proved, on the basis of one horse, and one set of pictures, but intriguing, nonetheless. It would suggest some truth to what I have bee told - that Raise a Native foreleg issues are more troubling in the tail male line than when he appears on the dam's side. Hopefully someone will research this in depth.
PS: Jessi, on your question of whether a "large" heart is engorged, as with a "large heart" in humans - Haun differentliates between a heart that is large because it is functioning improperly and one that is large in the sense of increased capacity.
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Well said monicabee, while I don't know the woman, and have no idea what her education is, my guess is that she doesn't have a strong background in science, or if she does it didn't take.
She's observing X chromosome inactivation, but doesn't make the jump in to this principal, and sure doesn't talk about it in any of her books.
Part of my frustation with both books is spin which overshadows the very real observations she has made. The spin irritates the people that would most benefit by her findings.
As for hind end/vs front end. What I'm seeing is the reverse.
Looks like the X, does carry structural information for the forehand of the horse.
Take a look at the Princequillo line horses. The Princequillo X seems to go along with a low head/neck set, thick neck and the same type of shoulder.
They look more like quarterhorses than TB's or at least the front end does to my eye.
If the photos are still up on the DB, take a look at:
Princequillo
Somethingroyal
Secretariat
Terlinqua
Storm Cat
or
Princequillo
Sharp Queen
Kris S.
Just for a hoot pull up Old Sorrel from the Allbreed side. This is the foundation sire from the King Ranch. His bottom line is unknown TB breeding.
Lower legs and feet seem to be under some other control. As is the hind end. Do you have other examples of hind end transmission? This in itself could be a interesting thread.
The Nearco hind end with the strong slope and low tail set seems to be non X related. Looks kind of like there is a batch of Barb genes popping out.
There is always a huge amount of resistance to new ideas. Seems to be a human trait, that only gets stronger as we age.
There are a couple of threads over on the all breed message board where folks don't seem to understand that giving a horse drugs is not going to cause the same change in offspring. Gads, Lemark rides again.
She's observing X chromosome inactivation, but doesn't make the jump in to this principal, and sure doesn't talk about it in any of her books.
Part of my frustation with both books is spin which overshadows the very real observations she has made. The spin irritates the people that would most benefit by her findings.
As for hind end/vs front end. What I'm seeing is the reverse.
Looks like the X, does carry structural information for the forehand of the horse.
Take a look at the Princequillo line horses. The Princequillo X seems to go along with a low head/neck set, thick neck and the same type of shoulder.
They look more like quarterhorses than TB's or at least the front end does to my eye.
If the photos are still up on the DB, take a look at:
Princequillo
Somethingroyal
Secretariat
Terlinqua
Storm Cat
or
Princequillo
Sharp Queen
Kris S.
Just for a hoot pull up Old Sorrel from the Allbreed side. This is the foundation sire from the King Ranch. His bottom line is unknown TB breeding.
Lower legs and feet seem to be under some other control. As is the hind end. Do you have other examples of hind end transmission? This in itself could be a interesting thread.
The Nearco hind end with the strong slope and low tail set seems to be non X related. Looks kind of like there is a batch of Barb genes popping out.
There is always a huge amount of resistance to new ideas. Seems to be a human trait, that only gets stronger as we age.
There are a couple of threads over on the all breed message board where folks don't seem to understand that giving a horse drugs is not going to cause the same change in offspring. Gads, Lemark rides again.
Interesting what you mention about the Barb hind end. I am very curious about traits that relate to the different sources of the thoroughbred. Some female families seem to have a strong type that recurs - even in the pre-photographic era. Certain painters, such as Stubbs, actually sought to represent the horse accurately enough to provide useful information. I had the impression, looking at pictures of successful horses from family one, that the were all the long, lean, leggy type - but that was a passing thought. It would take some research to see if it was consistently true or just a coincidence of the particular group of images. That's a great project for when I should really be doing something else, like right now!
Hi X-Factor,
A really fine post, well introduced.
Somrone asked about Danzing's heart - he's too small to have a large heart (he's listed at 15.3 on his Stallion Register Page, on stilts perhaps).
X-Factor, how much of the following is correct:
Haun was a huge Secretariat fan and wanted to find an explanation for his superiority. She heard of his large heart when he was autopsied and took it from there using some of the research from the folks down under. What is Haun's medical background?
I'm curious because Jessi brings up an important matter - larger than normal hearts in humans is a serious and life threatening condition.
Secretariat died of laminitis. Laminitis is linked to poor circulation. One of the effects of large heart in humans is impaired circulation. Well, you can follow where that goes.
I have no problem in believing that there are stronger and more effecient hearts in people and horses.
Regards,
Pete
A really fine post, well introduced.
Somrone asked about Danzing's heart - he's too small to have a large heart (he's listed at 15.3 on his Stallion Register Page, on stilts perhaps).
X-Factor, how much of the following is correct:
Haun was a huge Secretariat fan and wanted to find an explanation for his superiority. She heard of his large heart when he was autopsied and took it from there using some of the research from the folks down under. What is Haun's medical background?
I'm curious because Jessi brings up an important matter - larger than normal hearts in humans is a serious and life threatening condition.
Secretariat died of laminitis. Laminitis is linked to poor circulation. One of the effects of large heart in humans is impaired circulation. Well, you can follow where that goes.
I have no problem in believing that there are stronger and more effecient hearts in people and horses.
Regards,
Pete
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The accounts that I've seen indicate that Secretariat's heart was large, and perfect. No defects, or signs of pathology. Shams heart was also large but had signs of pathological enlargement. Key to the Mint's heart was large and in good condition.
Haun is a turf writer, and doesn't seem to have much science background. This I'm guessing from her books. They wander quite a bit without much logical structure.
That being said, she was a Secretariat fan from way back, heard about the results of the post mortum, and made the leap that became the two x factor books.
The researchers in Australia did the same thing, inspired by the giant heart of Phar Lap. And who knows what inspired the folks doing the study of Trotters.
Size doesn't seem to influence the size of the heart. The Domino/Sweep/War Admiral line has had the most winners, and these horses are not large. Despite what the Seabiscuit movie said. War Admiral was about 15.2 or so.
Don't know if it has been looked at, but a small horse with a lot of long lean muscle, ie the War Admiral type, might get a bigger kick from the large heart, than a large horse with sprinter type muscle.
"Secretariat died of laminitis. Laminitis is linked to poor circulation. One of the effects of large heart in humans is impaired circulation. Well, you can follow where that goes."
Don't know, one post on another thread suggested that he was just too fat. Wonder if Secretariat would have lasted longer if he'd been galloped under saddle every morning. It seems like a large number of X factor stallions have died early. It may be that they need more exercise than stallions with smaller hearts, and don't get it.
Despite all the critical things in this thread, Haun made some very interesting observations, and while I've got issues with the spin, and her lack of logic, her data seems sound.
Heart scores can be tested unlike Dosage, or Breyer speed figures, or any of the other ways people have created to try to understand a very complex problem.
Thanks to everyone who has taken the time to weigh in on this topic, it has been great to hear from other perspectives. Hope this will continue.
[/i]
Haun is a turf writer, and doesn't seem to have much science background. This I'm guessing from her books. They wander quite a bit without much logical structure.
That being said, she was a Secretariat fan from way back, heard about the results of the post mortum, and made the leap that became the two x factor books.
The researchers in Australia did the same thing, inspired by the giant heart of Phar Lap. And who knows what inspired the folks doing the study of Trotters.
Size doesn't seem to influence the size of the heart. The Domino/Sweep/War Admiral line has had the most winners, and these horses are not large. Despite what the Seabiscuit movie said. War Admiral was about 15.2 or so.
Don't know if it has been looked at, but a small horse with a lot of long lean muscle, ie the War Admiral type, might get a bigger kick from the large heart, than a large horse with sprinter type muscle.
"Secretariat died of laminitis. Laminitis is linked to poor circulation. One of the effects of large heart in humans is impaired circulation. Well, you can follow where that goes."
Don't know, one post on another thread suggested that he was just too fat. Wonder if Secretariat would have lasted longer if he'd been galloped under saddle every morning. It seems like a large number of X factor stallions have died early. It may be that they need more exercise than stallions with smaller hearts, and don't get it.
Despite all the critical things in this thread, Haun made some very interesting observations, and while I've got issues with the spin, and her lack of logic, her data seems sound.
Heart scores can be tested unlike Dosage, or Breyer speed figures, or any of the other ways people have created to try to understand a very complex problem.
Thanks to everyone who has taken the time to weigh in on this topic, it has been great to hear from other perspectives. Hope this will continue.
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Haun's X-Factor
Hi everyone.
Although I'm newly registered, in the pre-registered days I was a frequent visitor to the Message Board.
As it turns out, I may have a contribution to make to this particular discussion. I read Haun's books a few years back and decided to check out the theory for myself. The subject I picked was Secretariat's daughter, Terlingua, the dam of Storm Cat as I'm certain everyone here knows. However, where I want to differ with the person who kicked off the discussion in a very thorough & interesting way, is that -- given genetics -- it would not be the case, in fact, that all Secretariat progeny would be endowed with large hearts, or even that all of his daughters would be. This is because, genetically speaking, the X-chromosome is passed only from sires to their daughters, since females are XX. In other words, the dam in a secretariat mating gets 50% of the show here and what figures into this are dominant and recessive genes. A dam may exert a dominant influence on that Secretariat X (using him as an example) meaning that it will be less potent in a daughter's gene pool. So it's really not automatic -- it's Mother Nature and, as we all know too, she can be rather tough to control.
However, Terlingua's dam, Crimson Saint, also descends from a large heart gene pool and, so, Terlingua is an example of a "double copy" mare. She has double the chance of passing on the Secretariat heart, in other words. But these are "chances" not assurances.
What I did in my research was to track Terlingua progeny, especially Storm Cat and Chapel of Dreams, since we would want to look at Storm Cat daughters and Chapel of Dream sons to track that X. This does NOT mean that Giant's Causeway or other Storm Cat sons don't possibly have the X-factor capacity since, although they only received the Y chromosome from Storm Cat, they might have a strong X-factor on their dam's side that would be passed down to -- note -- daughters, not sons.
To return to the research. Given what I could find out about Storm Cat daughters (and this is hard going since many are unaccounted for as either runners or producers) there was, nevertheless, a trend that showed in terms of daughters who raced, as well as daughters passing on X-factor characteristics to sons, as would be the case with Buddha, for example, whose dam is Catinca. There were several examples of this kind: Terlingua to Storm Cat to a Storm Cat daughter to that daughter's son.
In the case of Chapel of Dreams, there was an instance of a son and a descendent of that son.
It was very, very interesting to work this through. However, I think the X-factor must be considered more in terms of additional data that a breeder/owner has access to, rather than the one most important influence. Certainly, there are correlations between the animals I looked at and their dosage information.
I sent the article, finished about a year ago, to the Blood Horse but they have yet to either accept or reject it!*** (Given when it was written there are names of other granddaughters that might be added today.) I have had thoroughbred owners read it and all gave it thumbs up.
I am currently looking at Nijinsky 2 re: X-factor research but this is in process.
I would, however, be happy to send the Terlingua/Storm Cat article off to anyone who's interested although, please note, it is copywritten to yours truly!
Although I'm newly registered, in the pre-registered days I was a frequent visitor to the Message Board.
As it turns out, I may have a contribution to make to this particular discussion. I read Haun's books a few years back and decided to check out the theory for myself. The subject I picked was Secretariat's daughter, Terlingua, the dam of Storm Cat as I'm certain everyone here knows. However, where I want to differ with the person who kicked off the discussion in a very thorough & interesting way, is that -- given genetics -- it would not be the case, in fact, that all Secretariat progeny would be endowed with large hearts, or even that all of his daughters would be. This is because, genetically speaking, the X-chromosome is passed only from sires to their daughters, since females are XX. In other words, the dam in a secretariat mating gets 50% of the show here and what figures into this are dominant and recessive genes. A dam may exert a dominant influence on that Secretariat X (using him as an example) meaning that it will be less potent in a daughter's gene pool. So it's really not automatic -- it's Mother Nature and, as we all know too, she can be rather tough to control.
However, Terlingua's dam, Crimson Saint, also descends from a large heart gene pool and, so, Terlingua is an example of a "double copy" mare. She has double the chance of passing on the Secretariat heart, in other words. But these are "chances" not assurances.
What I did in my research was to track Terlingua progeny, especially Storm Cat and Chapel of Dreams, since we would want to look at Storm Cat daughters and Chapel of Dream sons to track that X. This does NOT mean that Giant's Causeway or other Storm Cat sons don't possibly have the X-factor capacity since, although they only received the Y chromosome from Storm Cat, they might have a strong X-factor on their dam's side that would be passed down to -- note -- daughters, not sons.
To return to the research. Given what I could find out about Storm Cat daughters (and this is hard going since many are unaccounted for as either runners or producers) there was, nevertheless, a trend that showed in terms of daughters who raced, as well as daughters passing on X-factor characteristics to sons, as would be the case with Buddha, for example, whose dam is Catinca. There were several examples of this kind: Terlingua to Storm Cat to a Storm Cat daughter to that daughter's son.
In the case of Chapel of Dreams, there was an instance of a son and a descendent of that son.
It was very, very interesting to work this through. However, I think the X-factor must be considered more in terms of additional data that a breeder/owner has access to, rather than the one most important influence. Certainly, there are correlations between the animals I looked at and their dosage information.
I sent the article, finished about a year ago, to the Blood Horse but they have yet to either accept or reject it!*** (Given when it was written there are names of other granddaughters that might be added today.) I have had thoroughbred owners read it and all gave it thumbs up.
I am currently looking at Nijinsky 2 re: X-factor research but this is in process.
I would, however, be happy to send the Terlingua/Storm Cat article off to anyone who's interested although, please note, it is copywritten to yours truly!