Re: Cannon Bone measurements

[CMKSAGEHIL@aol.com]

Tom Ivers makes the excellent point that no matter the bone, the problems
generally come from too much speed too fast.  Tom wrote the book on dynamics
of bone, but I think it is worth mention in this format (I hope Tom will add
more detail) that bone actually DE-mineralizes for a period of time at the
onset of conditioning (several weeks) and is at its weakest at about the point
in race training that the horse starts to feel really good metabolically.
Hence, the speed is poured on and the horse breaks down.  We see this to a
lesser degree in this sport, but nonetheless, we see it.  As the bone
reconfigures itself to the new stresses being added, it begins to remineralize
in a stronger fashion, and only after this is accomplished does one really
have strong bone.  

As to big bone in young horses, my experience is anecdotal, but I feel that
there is a tremendous genetic variation in density of bone.  I would tend to
want to select horses from families that hold up, regardless of circumference,
and especially prize individuals from those families with larger bone.  I
think the density issue relates more to a QUALITY of bone that is impossible
to measure with a tape measure but is evident in the eye of the experienced
horseman as clean, flat bone.  I know I have found a strong correlation
between structure that I admire and whether I see that horse back year after
year on the circuit, and I don't tape all those horses as I vet them in...  I
know there have been some radiographic studies done about this, too, and while
I can't recall the bottom line, I remember finding them interesting.  Tom, do
you have any more info about that?

Heidi Smith, DVM--Sagehill Arabians (Oregon)