Ridecamp: Re: [RC] Wine Country/Gastroguard

> Also, related horses may be horses that were raised at
> the same or similar facilities, and that may be more of
> a factor than the genetics themselves.

Actually, we've tried to look at a much broader picture than just immediate
parent/offspring/sibling sorts of relationships when making comparisons in
performance, and are often comparing horses from broad general families that
are raised all over the country--both in terms of successes AND failures.
Part of accurately looking at genetics is taking into account the very sorts
of things you mention.

Where veterinarians often go amiss is looking at a breeding farm where ALL
of the closely related horses have a problem, and saying "this looks
genetic"--when in fact, if the problem were genetic, it would tend to
segregate, and only a percentage would have the problem (the percentage
varying depending on the mode of inheritance).  Hence, in the above sort of
scenario, the problem is likely environmental.  By the same token, people
will point to a success story and say "that problem can't be inherited,
because look, here is a horse bred like that that is excelling."  Given
segregation, one would only expect to see the problem in the appropriate
percentage of offspring, not all of them, so yes, the problem may well still
be genetic, and the success story is just the lucky horse that ended up in
the "good" half that didn't get that gene copy, so to speak.

Heidi


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