Large Heart Gene

Post Reply
frankel13
Posts: 32
Joined: Thu Nov 21, 2013 4:03 pm

Sat Jan 25, 2014 4:36 pm

I was reading about the large heart gene that some racehorses appear to have. Assuming that this can be detected by a scan, are foals actually scanned for this prior to significant sales (eg Keenland September). This could be useful information for all concerned.

Also do we know which leading sires carry the gene and which don't?

Thanks.
TBird
Posts: 266
Joined: Thu Sep 19, 2013 9:09 am

Sat Jan 25, 2014 5:28 pm

We don't scan our own foals but buyers will occasionally ask to do a scan at a sale, which we of course allow. So buyers who are interested in the information are able to obtain it.
User avatar
Life At Zen
Posts: 1655
Joined: Thu Sep 12, 2013 6:52 pm

Sat Jan 25, 2014 9:23 pm

I had no idea such scans were even done. You learn something new everyday!
A R R O G A T E
Paradise Woods, Lady Eli, Songbird, Ziconic
Gormley, Royal Mo, Shaman Ghost, Constellation

Once upon a time there was a horse named Kelso.
But only once. ~Joe Hirsch
User avatar
Ridan_Remembered
Posts: 1447
Joined: Sun Nov 03, 2013 2:15 pm

Sat Jan 25, 2014 9:47 pm

frankel13 wrote:I was reading about the large heart gene that some racehorses appear to have. Assuming that this can be detected by a scan, are foals actually scanned for this prior to significant sales (eg Keenland September). This could be useful information for all concerned.

Also do we know which leading sires carry the gene and which don't?

Thanks.
Princequillo carried the gene, which is passed from sire to daughter to her offspring. So Princequillo passed it to Somethingroyal, who passed it to Secretariat. This might very well explain why both Princequillo and Secretariat were great broodmare sires while their male lines didn't have strong sires to carry on.

By the way, on his death at 23, a necropsy showed that Sham also had a larger than normal heart. His dam, Sequoia, was also by Princequillo. So you see, in and of itself, the large heart is no guarantee of wins on the racetrack. In both the Kentucky Derby and Preakness, Sham finished 8 lengths ahead of all the other horses except one. Secretariat finished 2 1/2 lengths in front of Sham. The Belmont forever separated these two maternal grandsons of Princequillo because there was some indefinable something remarkable about Secretariat that Sham didn't possess even though both colts had the large heart.
TBird
Posts: 266
Joined: Thu Sep 19, 2013 9:09 am

Sat Jan 25, 2014 10:09 pm

Ridan_Remembered, you're right to point out that a large heart is not guarantee of wins. It's not guarantee of anything really, nor even necessarily an indicator of desireable traits like systemic efficiency or superior ability. Actually an enlarged heart is one symptom of a diseased heart. So while there are certainly people promoting and making money off the "exciting discovery" of the large heart gene, there remain as many skeptics as there are believers as to how meaningful the testing really is.
Secretariat4ever
Posts: 21
Joined: Thu Sep 12, 2013 9:13 pm

Sun Jan 26, 2014 12:11 am

Obviouly Secretariat heart was not diseased. The gene for a larger heart is simply a gene for a larger pump which carries more oxygenated blood to muscles . This decreases the latic acid concentration and therefore improves muscle performance. You are talking of cardiomyopathy which of course is a diseased heart.
LBM
Posts: 8
Joined: Sun Jan 05, 2014 3:52 pm
Contact:

Sun Jan 26, 2014 9:09 am

I have often wondered why this matter has not been advertised by stallion managers.
Surely a vet should be able to determinate if a heart size is unusually big, shouldn't he/she? Some breeders would see that as a desirable trait to get it passed to their offspring and therefore it would make the sire more popular and profitable.
Why we have to wonder that trait is passed on just by studying pedigrees and guessing when a simple scan would assure us beyond doubt ?
TBird
Posts: 266
Joined: Thu Sep 19, 2013 9:09 am

Sun Jan 26, 2014 10:38 am

LBM wrote:I have often wondered why this matter has not been advertised by stallion managers.
Surely a vet should be able to determinate if a heart size is unusually big, shouldn't he/she? Some breeders would see that as a desirable trait to get it passed to their offspring and therefore it would make the sire more popular and profitable.
Why we have to wonder that trait is passed on just by studying pedigrees and guessing when a simple scan would assure us beyond doubt ?
One stallion that has been advertised repeatedly as having a large heart is Kitalpha, giving breeders who are looking for that trait a stallion to take their mares to.

Most breeders think things like pedigree, performance and the ability to sire high class winners, are more important qualities to look for.
aethervox
Posts: 193
Joined: Wed Sep 18, 2013 11:48 am

Sun Jan 26, 2014 2:26 pm

In her third book, Marianna Haun says there are two versions of the large heart gene, one passed down through Eclipse and one from the Darley Arabian (which is what Secretariat had). The Darley heart gene is passed with a skeleton that has one less lumbar vertebrae, which gives the horse a shorter back and longer stride.

She points out that when Secretariat was measured for a statue, the length of his legs from elbow to ground was 4 inches longer than the length of his back from withers to point of hip.

Of course Secretariat also had other attributes that made him a champion -- he had the lung capacity to support the heart and his gait, according to experts was nearly perfect, with very little wasted energy.

I think that the large heart is most useful to horses when racing at distances over a mile.

As an example, Verrazano was scanned as a yearling and had a normal sized heart. http://performancegenetics.com/wp-conte ... -2010c.pdf He won at distances up to a mile and an eight, but never won at a mile and a quarter.

aethervox
User avatar
Northport
Posts: 2089
Joined: Fri Sep 13, 2013 12:13 pm
Location: probably near the food

Sun Jan 26, 2014 2:41 pm

aethervox wrote:In her third book, Marianna Haun says there are two versions of the large heart gene, one passed down through Eclipse and one from the Darley Arabian (which is what Secretariat had). The Darley heart gene is passed with a skeleton that has one less lumbar vertebrae, which gives the horse a shorter back and longer stride.

She points out that when Secretariat was measured for a statue, the length of his legs from elbow to ground was 4 inches longer than the length of his back from withers to point of hip.

Of course Secretariat also had other attributes that made him a champion -- he had the lung capacity to support the heart and his gait, according to experts was nearly perfect, with very little wasted energy.

I think that the large heart is most useful to horses when racing at distances over a mile.

As an example, Verrazano was scanned as a yearling and had a normal sized heart. http://performancegenetics.com/wp-conte ... -2010c.pdf He won at distances up to a mile and an eight, but never won at a mile and a quarter.

aethervox
that is really interesting, I really don't know anything about large hearts in thoroughbreds but this is a very useful thread!
weeeeeeeee
tonno100
Posts: 15
Joined: Sat Nov 02, 2013 6:30 pm

Mon Jan 27, 2014 4:57 am

Complete nonsense.

If it worked everybody would not just want to do it, they'd have to do it. It doesn't, so they don't.
User avatar
Katewerk
Posts: 608
Joined: Tue Sep 17, 2013 11:30 pm
Location: Canada
Contact:

Wed Jan 29, 2014 11:40 am

tonno100 wrote:Complete nonsense.

If it worked everybody would not just want to do it, they'd have to do it. It doesn't, so they don't.
I don't think that's entirely fair. As has been mentioned, it's only one factor out of many that make up a successful racehorse - length of stride, soundness, courage, size. Plenty of horses succeed without one of the aforementioned factors in their favour. The question is whether it's advantageous, and there's plenty of evidence that it is.
frankel13
Posts: 32
Joined: Thu Nov 21, 2013 4:03 pm

Wed Jan 29, 2014 5:38 pm

When it's discovered upon his death that possibly the greatest racehorse of all time (Secretariat) had a heart almost 3 times larger than the average thoroughbred then questions should and have been asked. From what I can see nothing has been proved nor disproved, but if I was lucky enough to be able to afford to race or breed these fantastic animals then I'd be all over this theory like a rash. It gives the opportunity to acquire a nice animal(s) at a price that may be unthinkable in a few years time if the link is proven.

A recent article I found on this is shown below:

http://www.pedigree-dynamics.com.au/x-m ... ne-theory/
TBird
Posts: 266
Joined: Thu Sep 19, 2013 9:09 am

Wed Jan 29, 2014 5:59 pm

frankel13 wrote:When it's discovered upon his death that possibly the greatest racehorse of all time (Secretariat) had a heart almost 3 times larger than the average thoroughbred then questions should and have been asked. From what I can see nothing has been proved nor disproved, but if I was lucky enough to be able to afford to race or breed these fantastic animals then I'd be all over this theory like a rash. It gives the opportunity to acquire a nice animal(s) at a price that may be unthinkable in a few years time if the link is proven.

A recent article I found on this is shown below:

http://www.pedigree-dynamics.com.au/x-m ... ne-theory/
I read the article. It's interesting to me that the author used Eavesdropper as his example of a horse with the "coveted" Large Heart Gene. Eavesdropper was only moderately successful as a racehorse and he was a failure as a sire in the U.S. (35% winners, 0% stakes winners.) So what was his LHG supposed to have helped him with?
frankel13
Posts: 32
Joined: Thu Nov 21, 2013 4:03 pm

Wed Jan 29, 2014 6:40 pm

TBird, I only included that link because it was recent (written a month ago). For me a more interesting article is shown below;

http://www.horsesonly.com/crossroads/xf ... eart-1.htm

I just chanced upon this topic whilst browsing the web and found it interesting. Is it positively talked about in breeding circles, treated as mumbo jumbo or not discussed at all?
BaroqueAgain1
Posts: 9879
Joined: Sat Sep 14, 2013 6:16 pm

Wed Jan 29, 2014 6:54 pm

If I have read correctly, the Large Heart Gene possessed by Secretariat is passed through the daughters, which may be one reason Big Red ended up being a really good broodmare sire. So, perhaps it would be worth following Eavesdropper's daughters to see if he also has success there?
tonno100
Posts: 15
Joined: Sat Nov 02, 2013 6:30 pm

Thu Jan 30, 2014 2:52 am

There are plenty of people scanning hearts, and they have no more success than anyone else. In fact, I can't think of any really top buyers who do it, but they still get out a higher % of stakes winners than the heart score nuts.
Post Reply