Martian Tiger has a pretty impressive pedigree. He is a 1988 TB gelding and I’m in the process of putting him into the Del Mar database.
Interestingly enough, on first glance, like the other upper level event horses that I’ve checked, he appears to have the indicators that he has a larger than normal heart. Pretty cool 
Libby
[This message was edited by Bensmom on May. 08, 2002 at 10:05 AM.]
<BLOCKQUOTE class=“ip-ubbcode-quote”><font size="-1">quote:</font><HR> More thoughts: since the x chromosome is significantly bigger than the y, then actually the dam is passing
on about 70% of the genetic material to colts (she gives the x and stallion gives the smaller y) and both
dam and sire each give the same amount (through x chromosomes) to fillies. <HR></BLOCKQUOTE>
The X may contribute 70% of the X-Y combination, but there are many more chromosomes (at least 20, I forget the actual number), so the dam contributes less than 5% more genetic material than the sire to her male offspring.
The research that’s being done on the x-factor large heart gene has been utilized mostly in evaluating racehorses. My pet theory is that in most successful event horses, we’ll find the same thing. It passes through the female line only as it is linked to the x-chromosome, so if you can pull the pedigree and trace back to four of the large heart lines, and it descends through the female line, you can guess that the descendant will have a large heart. When you check the option to have del mar show you the x-factor in the pedigree it doesn’t light up as many indicators as I found.
Which may mean that, as an rank beginner with this stuff, I’m wrong about the number of places it showed up, or that the computer that generates the pedigree automatically discounts any chance of it passing through a sire, though sires can and do pass it to daughters.
Confused yet? 
I chatted with an upper level rider about using this info to pick event prospects at Red Hills, and after I said “well, I know you can’t ride the pedigree, but . . .” He made a great point and said, “No, but the Germans have shown us that you sure can stack the deck in your favor!”
Very interesting stuff, and I’m packing a couple of folders with research to see if my theory might be correct.
Both of my boys have the indicators of the large heart gene, and both of our vets are very interested in the research – one is a race horse breeder and the other worked in Ocala when first out of vet school. At some point when I’ve paid down my bill some, I’m going to see if we can ultrasound the two of them and check and see if my pedigree research matches their actual physical hearts.
Or maybe I’m just a nerd who would rather read about this stuff than do my real job of practicing law 
Libby
We took Riverdale to visit an equine cardiologist at Purdue University. Cost was $180 – minimal in my mind. At a teaching hospital like Purdue, you get access to amazing equipment and minds for very minimal amounts of money. We also had a rather large audience of students who needed to learn about heart murmurs.
I’d encourage you to look for an equine/large animal cardiologist at a major university near you. In our area, both Purdue and the University of Illinois have equine cardiologists on staff.
subk, that is exactly what made Secr. a great dam sire. He gave his big heart x to all of his daughters, some would be single copies and some doubles. Weekend Surprise is a double copy mare by Secr. She was the dam of AP Indy and Summer Squall.
Bensmom, I don’t think you are wrong about the Del Mar database being a bit off on the x-factor. One of the horses in our barn is a Buckpasser grandson (Buckpasser and his dam are both single copies acording to Haun’s book) and they are not marked by Del Mar.
It appears that I wasn’t paying attention back in March when my AQHA Racing Journal came – there is a new article by Marianna Haun in it. It has more info on some of the racing quarter horse bloodlines, and even more emphasis on the physical characteristics tracing along with the large heart, though still no “easy find” study chart to find them.
Interesting stuff – I remember on the thread about racing bred QHs that several of us on the board have and event them. For those that have appendix/racing bred quarter horses, how are they in dressage, as a general rule? I’d like to follow up on yet another theory
Libby
I don’t get the technical part of this at all, but can someone look at Golf Course Spy on Delmar and tell me if there’s a chance that he has this large heart gene? Also, what are the physical characteristics? Thanks.
Interesting to see Swaps coming up, since this is something I’ve been looking at.
Northlight (Diamondham) is a descendant of Swaps on both sides:
Swaps bred to Bimlette (double copy mare) produced No Robbery (single copy stallion)
No Robbery bred to Radmar (possible double or single copy mare) produced Morning Smiles (definetely single copy and possible double copy mare)
The it gets interesting…
Morning Smiles is bred to Our Native, who won more than $400,000 in the early 70’s (great success) and is a possible large heart stallion. That produced Mulberry Moon, dam of our horse.
Also, Radmar’s dam is Radio Time, and her sire is Eight Thirty.
Of course, Northlight cannot have an X from his sire’s side, but still he gets 1/2 of his genetic makeup from their, and there’s more to peak perfromance than a large heart. His sire is Vanlandingham, an Eclipse Award winner who turned out to be a relative bust at sireing American flat racers. Vanlandingham is also a descendent of Swaps. However, you have to look a bit further at what Vanlandingham passes on… His progeny mature in their 5th and 6th years. Some have been extremely successful steeplechasers. So while he doesn’t pass on the 2 and 3 year old brilliance that is fashionable in modern flat racing, he produces durable distance runners and jumpers - perfect for upper level eventing, I imagine.
Jeanne
From my research, there are some interesting things about Swaps. He won more than $800K racing in the 50’s - one of the most dominent horses in his day. But he was owned by a renegade guy, and is widely believed to have been badly handled. Imagine what he might have done properly handled! He is considered a large heart horse, and his persistence and performance under less than optimum conditions give anecdotal weight to that. I’m thinking that perhaps the Swaps line may be very helpful in “building” a top event horse - certainly at Rolex we saw the advantage to performance under tough conditions.
Thanks for sharing your amazing insights. We think Riv’s a wonderful horse. I, too, wonder where Al Fijar is and what he’s doing!
When I pull her pedigree up - I’m seeing 30 out of 62 (5 generation) as blue - I see entire bottomside in 4th generation in blue - there isn’t a red line anywhere
would someone doublecheck for me?
Ok, now that my staff meeting is over <gag>
Several mentions of the physcial characteristics are scattered in both books, and my original intent was to make a list and to search through the books to find them all so I would make sure not to miss something, but I haven’t done that yet, so here is the quick rundown, from chapter 8 in the second book:
She says that they began following the ears of lines, after Penney Chenery (owner and breeder of Secretariat) noticed that a mare used in the project had “Secretariat’s ears.” A geneticist at UoK involved in the project beineves that the ears are a physical marker for a genetic trait on the x chromosome. The ears can come up the female line from a long way off. She states that it has become a shortcut for measuring horses.
She says that the difference in ears can be difficult to spot, but the small rounded ear of Mahmoud is easy. When viewed from the front, the ear has a leaf-like quality which is unmistakable. Northern Dancer, Halo, Spectacular Bid, and Fusiachi Pegasus all have this ear.
Princequillo: small curly ears, in addition, they will have a similar hip, eye and nostrils.
Blue Larkspur – I can’t put my hands on the info on those horses.
War Admiral: medium sculptured ears. There is more about physical similarities in the chapter on War Admiral, and that is Buzzy’s large heart, so I was thrilled to find that:
Very high level of energy (gee, and the vet stated yesterday that he isn’t sure he’s ever dealt with a horse as engergetic as Buzz!), size: War Admiral was only 15.2 and dark bay – supposedly the size and color of his broodmare size, Sweep. (Buzz is dark bay and almost 15.2) Medium size sculptured ears, large eyes, plenty of space in between his jaws, and a fine muzzle with over sized nostrils. (yep, Buzz has all of the above – the space inbetween his jaws is astonishly wide and deep and his nostrils are great big for the size of his head). Prominent withers, beautifully sloped shoulder, long forearms and short cannons. (yep, got those two, though not a skinny wither, but quite well built and well, prominent) Hard to keep weight on.
Horses with War Admirals head: Escena, Lemon Drop Kid, Tale of Two hearts, Desert Secret, Affirmed, Surfside, Seattle Slew, Silver Charm and Cigar.
The eyes, interestingly enough, are set where they can see more easily down the lane. The head, top line and front end pass to these horses. Some have been taller, but typically they are between 15.3 and 16 hh. War Admiral was said to travel more like Sweep than Man O’War, which makes sense if you consider that the front end follows the x expressed. There is an unusual way of going with teh front leg rising higher from the forearm than is usually seen (This is especially exciting, since one of the reasons we liked Buzz’s movement was this exactly. He lifts up with his forearm and shoulder, we hoped making it easier for him to do dressage)
All of the above info is lifted expressly from the second x-factor book, but there is no chart available in one place to find the physical characteristics. I will have to go through both books carefully to find them all.
Because of the chaos yesterday, I haven’t got any new shots of Buzz (this head shot was taken when I first got him, and his coat was still straggly and he had um, bad hair) but I’ll post one jpg of him and then one of Cigar that first caught my eye and see if y’all see the resemblance. I see similar “expression” about them. The better photos I hopefully can post tomorrow.
Libby
So, if my horse’s pedigree on DelMar has all blue underlines on the whole bottom line, he probably has the x-factor? Did I read that correctly?
Oh, his name is “Shafouri” with the (IRE) designation.
He did race, winning about $80,000 (converting the english winnings into US$) and he raced until he was 7 1/2. He is a fantastic horse – very talented over fences, easy to ride, great temperment, and learns quickly. Although he is now a gelding, science has provided me the chance to breed him in the future
[QUOTE]Originally posted by NancyL:
So, if my horse’s pedigree on DelMar has all blue underlines on the whole bottom line, he probably has the x-factor? Did I read that correctly?
Oh, his name is “Shafouri” with the (IRE) designation.
Nancy, I looked up your horse and you are not reading this correctly. Del Mar puts all mares in a horse’s pedigree in blue type with thin underlines, and all stallions in a pedigree in black type with thin underline. This underline is the HTML code for “click here to get this horse’s pedigree.” This is NOT the x-factor underline. The x-factor underline is heavy red or blue. In your horse’s pedigree, Artic Rullah in the 5th generation is the only red underline, and there is not heavy blue (double x-factor) underline, so it is unlikely that your horse has the gene based on Del Mar.
<BLOCKQUOTE class=“ip-ubbcode-quote”><font size="-1">quote:</font><HR>When i did it on Del mar…at the top it says Highlight: X-chromosome…so i clicked thtat and it had
everything that carried down in a darker colored background…i hope thats what we were supposed to look
for lol! <HR></BLOCKQUOTE>
If you click on highlight X chromosome, it highlights all the horses from which the end horse MIGHT possibly inherit an X chromosome. But it has nothing to do with whether or not the X chromosome has the “X-factor” for the large heart.
That’s actually really interesting. Spot’s dam is a pure TB, but for some reason she’s not on the TB site, but is on the all breeds site (Chantilly Gray, by Great Substance out of Credit Risk) where I don’t see an x-factor marker to check? Maybe I don’t understand the site well enough.
I’m assuming that a larger heart means more capacity to pump blood and thus more efficient under high stress situations (thus, in an event horse, better able to cope with x-c required athletic output at high speed), so it would make sense that successful horses might be more likely to have the genetics for it. The theory reasons that since so many upper level event horses are geldings and many (not all) of the stallions aren’t going Advanced or 4* before they start breeding, it may be harder to use performance as a touchstone for genetics, and thus the pedigree research would be indicative?
-GotSpots
You know, I actually rode Riverdale once several years ago, had forgotten- he was very green at the time, but SUCH a nice boy, well mannered- glad to hear you have him, and good luck!!
Janet, thanks, it looked to me like she (Singing Native) might possibly have the X factor, but wasnt sure. She is a big hearted mare, even if she is not actually “big hearted”. 
Indecision may or may not be my problem.
In addition to the “Big Four” stallions mentioned above, there is also a compilation of mares that are generally regarded to be double copy - that is both X chromosomes carry the predisposition to have a larger than normal heart.
A mare inherits her sire’s only X chromosome, so a sire that is “proven” or “regarded” to have a large heart has a 100% chance of passing that on to his daughters. The same mare inherits only one of her dam’s two X chromosomes. So if her dam was a double copy mare, then the daughter will inherit the “large heart” factor (X factor). If the dam had one “large heart” X and one “normal” X, then the daughter has a 50% chance.
Our Northlight (Diamondham)is a horse (gelding), so he has a Y from his sire’s side, so no possibility of “X factor” from the sire side. On his dam’s side, Mulberry Moon has a possible large heart X from both her sire (Our Native) and her dam (Morning Smiles). So Norhlight’s X may pass on large heart.
The trouble with proving this is that the final answer comes either from expensive diagnosis or from autopsy. And Haun has not opened her research to scrutiny from others, so some question the robustness of her theories.
But its interesting. What seems to make some sense, is that almost all of the top racing horses track positive for this trait. Not to say that all horses with this trait become top race horses - in fact, only a small percentage become really succesful.
Well, I would think if you love TB racing that helps 
Suck it up and buy the Blood Horse. It’s expensive, BUT you get a couple of great perks. Tons of great info on horses, racing, etc. You also get a stallion book and an index. The Index has an incredible amt of info in it,like barns, tainers, etc. IF you watch TVG 24/7 like my dad, you’ll be even better at knowing who looks good and who doesn’t. He even has his favorite commontators and can tell you which person does a better job picking winners at what track.
I WISH I had more info on Mellvin’s dad other than he was “you know some TB at the farm”
Hollyn
is listed as having at least a single copy mare as his dam. Again, I would guess that because Halo’s dam was listed as a double copy mare, and that he therefore, would have the x-factor, and would pass it to a daughter, his dam might actually be a double copy mare. If that’s true, i.e. she has both her x-chromosomes with the gene, then he will have gotten it from her.
On the Del Mar site, the FAQ tells you that if you check “yes” on the option to show x-factor it will put a red line under single copy horses and blue under double copy ones.
This is pretty cool – do you guys think that we are finding the x-factor present in horses that we’ve chosen to event with because the traits that go along with the large heart – boldness, a desire to gallop, the strength to gallop, are what we’ve been choosing event horses based on, and that therefore we’ve been unconciously selecting large hearted horses all along? i.e. that “look of eagles” that Jimmy Wofford talks about – interesting to see if that corresponds to these other physical traits.
Libby
Since you are looking at a gelding, from a large heart perspective he has only one X chromosome and that comes from his dam’s side. So don’t worry about the sire side
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