Inexact Science - By Dan Liebman

In Ireland last week trainer Jim Bolger and scientist Dr. Emma­line Hill announced they have formed a company to promote the Equinome Speed Gene Test, which they claim will help horsemen identify the optimum distance for a particular

Bolger was quoted as saying the test is “without a doubt the most important thing that has happened to breeding since it began over 300 years ago.”

I suggest it could be the exact opposite.

There is nothing exact about breeding horses, and the fact that it is such an inexact science is one of its greatest traits and most alluring appeals.

There are many exciting possibilities related to the sequencing of the genome for any animal or species. But in horses, determining a speed gene is not one of them.

If researchers are able, for example, to identify a gene that determines whether a Thoroughbred will bleed or possess any one of a number of diseases, then that might be “the most important thing that has happened to breeding since it began over 300 years ago.” But being able to use genetics to breed a horse that can win at six furlongs but not at eight is, well, not something breeders should be interested in.

The beauty of breeding is that there are so many different phil­osophies among the men and women who make the decisions about which broodmares are mated to which stallions.

It may be as simple as this: “I own a share in a stallion so I need to pick a mare to breed to him.”

Every mare owner has heard this: “Sorry, book full, choose another stallion.”

There are those who believe strongly that inbreeding should be sought in every mating, and those who feel quite the contrary.

Breed an unproven mare to a proven stallion. Ever heard that one?

How about breeding to first-year stallions because they are well-received at public auctions? Well, until the economy headed south, that is.

Breeding a small mare to a large stallion has always seemed a good idea. That is genetics, isn’t it?

Whether breeders know it or not, they have been using genetics in their matings forever. The aforementioned inbreeding is selecting to infuse a pedigree with the genes of one sire line over another. Inbreeding to certain female families, or seeking the descendants of, say, La Troienne, are other examples.

Breeders know which stallions are more likely to throw sprinters and which are more apt to sire distance runners. They also know this about their mares, and hence the decision-making of planning matings.

Numerous statistics aid breeders in evaluating speed versus stamina, things as simple as average winning distance and dosage, the latter merely a mathematical equation that seeks to estimate the balance of speed and stamina in a given pedigree.

Of course, being a trainer, Bolger knows what all conditioners know, that breeding is merely the genes within the animal. The expression of those genes depends on many other factors, such as feed, shoeing, veterinary care…and, oh, yes, training.

A few years ago when Dolly the sheep was cloned and Thoroughbred folks were discussing the impact cloning could have, I suggested what I thought would be an exciting experiment: Take 20 clones of the same Thoroughbred and give the animal to 20 different trainers. Wouldn’t it be interesting to see how the same horse would turn out in the hands of 20 different trainers?

Geneticists, scientists, and researchers are doing exciting work now that the equine genome has been mapped. Perhaps one day they will identify the markers that can help the industry breed a sounder horse, or their work will lead us to a cure for grass sickness or help us prevent osteochondritis dissecans (OCD).

But do we need a researcher to tell us to breed mare “A” to stallion “B” and you will be assured a horse whose best distance is at a mile?

No, we don’t.


Leave a Comment:


this is  codswallop!!! there is no way  to check  for a speed gene(imho) it seems  so silly . breed graded winners to graded winners  and  you will find  that most of  the time  you will get a foal  that will win a graded race.  the old breed  the best  to  the best  and hope for  the best, also breed 2 rival stallions   example  the dr fager  damascus  cross  or the easy goer sunday silence cross  that works too!

26 Jan 2010 8:17 PM

Definitely not. Breeding isn't an exact science. There have been too many high dollar sale horses that never even see the racetrack much less finish an actual race. This proves that no one has the exact formula for churning out winners.

The best you can do is breed the best mares to the best stallions and hope you get one that not only can run, but one that WANTS to run!!

26 Jan 2010 10:21 PM

Right on. : )

26 Jan 2010 10:43 PM

I'm horse stupid, but love the animal.  Is it commom to breed a mare every year?  To me it seems excessive, but what do I know.  Comment please.

27 Jan 2010 12:33 AM

One marker that will help breed a sounder horse: Don't breed to an unsound one to begin with...and I've got a top stallion in my mind right now that produces brilliant 2-year-olds but a lot of his 3-year olds breakdown... but the market will insist on using him...and his sons...and his daughters...and we'll be bummed as they retire as early 3 year-olds and we'll grieve when they don't survive their breakdowns, BUT we won't stop using them in the breeding shed.

27 Jan 2010 7:13 AM
Ann in Lexington

Ronnie, in the wild the stallion repeatedly covers each of his mares every spring when she gets in heat. If she is healthy enough, she gets in foal; if she needs a break, she won't. With an 11.5 month (average) gestational period, she'll have them just about every year. Yearly foals is natural, not abuse.

27 Jan 2010 9:34 AM

Yes, it is common to breed a mare every year as long as she is capable. A veterinary issue may keep her from being bred; a late foaling date may cause her to miss a year. Otherwise, yes, they are breed every year.

27 Jan 2010 10:37 AM

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