The genetics of fracture risk in the TB

[Pan Zareta]

A genome-wide association study demonstrates significant genetic variation for fracture risk in Thoroughbred racehorses

[diomed]

Pan Zareta, thank you for posting this information. It's about time the TB industry started looking at real science when it comes to genetics. Other domestic livestock have been doing it for decades. Need to catch up with the rest. My brother works in that industry for dairy cattle and what they know based on the genome is just amazing. We discuss this a lot. He still can't believe that they don't allow Embryo Transfers in the TB.

[Pan Zareta]

You're welcome.

The industry didn't really have the necessary tools to employ full genome-based profiling until a few years ago. Translating genome-wide association studies for a wide variety of traits into recommendations for breeding the fittest possible TB athlete is probably going to be a bit more complex than optimizing cattle breeding for beef and milk production.

ET (and AI) definitely have their advantages but allowing any form of assisted repro in the TB in the USA would open the gates of litigation hell, just like it did w/ the AQHA, and eventually compromise the value of domestic TBs on the int'l. market.

[LB]

I wish the study had used a larger sample size than 522 horses.

[vineyridge]

Considering that they used dead horses who broke down racing in the UK, 250 seems to me to be a large number indeed.

[Jeff]

The study proved nothing, it did.not take into consideration the obvious; that many horses break a leg simply because they take a bad step, that's all it takes, the bad luck of a bad step. The study does not take into consideration the training methods of the horse, it might well have better been a study of which trainers to avoid rather than genetics.

A far more predictive method to get a good runner would be to use Stan's method; get some Buckpasser on the bottom of the pedigree.

Genetics might be a good way to determine which cow gives the most milk or which bull produces offspring with the most muscle mass and weight gain, but judging the heart will and spirit of the thoroughbred horse by his genetic codes; I don't buy into it, just another gimmick, somebody will come out with some gimmick; send us a.few hundred dollars or pounds and we'll tell your horses odds of breaking a leg. One things for sure, a slow plodder won't ever break anything.

[Jeff]

The study didn't take into consideration how many race starts the subject population had, obviously the horses with more starts are at risk. How many days of rest did the subject horses have between races their past few starts? I'd wager the horses with the least rest between races were the ones more likely to be the ones to break down. Or one could argue just the opposite, that the horses didn't get enough training and were unfit to be inthe races they were in to begin with, they spent to much time standing in a stall. Of course there's always those willing to part with their money for a new gimmick. I 'll stick to Stan's method though, get some Buckpasser in the pedigree.

[Jeff]

It needs also to be mentioned that National Hunt horses in the U.K. do not have to be thoroughbred horses, they can be any breed of horse, or half-bred horse, so their genetic. markers indicating their predisposition to break a leg ( if it exists, and I don't believe it does) would have nothing whatsoever to do with the purebred thoroughbred. We can fairly predict a 1/2 bred Irish draft/ TB National Hunt horse going over the jumps in the U.K. has nothing to do with flat racing purebred thoroughbred horses. If a National Hunt horse in the U.K. breaks a leg, again, I think it's more likely he was unlucky to make a bad step landing after a jump, his genetic markers have nothing whatsoever to do with the bad luck of a bad landing that might result in a horse breaking his leg.

[Pan Zareta]

...get some Buckpasser in the pedigree.

A little Buckpasser in the pedigree is seldom if ever a bad idea but if you think his x might be relevant to decreased fracture risk or much of anything else, have a look at Figure 1 in the report and think again. Typically flat signal from the x.

[Joltman]

It would be good to see a completely different study, maybe in a different country, that would confirm (or not) these results. They may be quite significant - even with all the other variables.

jm

[Joltman]

Also it would be interesting to study those control subjects that had the same geneitic characteristics of the positive factors, but didn't break down. i.e. did they have other fractures in their careers (non lethal) or were they trained differently or something?

jm

[vineyridge]

It's a start. Finding that a particular form of gene was found that gave a horse carrying it more than 3 times the likelihood of a catastrophic fracture seems to me important. Also that another gene version made a horse carrying it almost twice as likely NOT to fracture also seems worth further work.

[vineyridge]

One wonders if the study considered Lasix/salix/furosemide use at all, since there is evidence that it upsets the calcium metabolism.