health question

[Terry <canajello@echoweb.net>]

This is a strange question, but with all of the experts out there
perhaps I will come to a better understanding of what is going on with
my 12 year old Arab gelding.
HISTORY: Shahin came to me when he was about 8 because nobody wanted to
fuss with this hyper horse. He and I hit it off and it was he who led me
into endurance riding. He and I began our first season together with 25
milers because I wanted to make sure he was strong and able. He loved it
and we just flew through our first 100 miles of rides, then he came down
with a slight lameness in his right foot. It looked low and in the
pastern. X-rays couldn't determine what was wrong. I laid him off for
the rest of the season. The next year I began conditioning slowly. He
finished his first 50 miler with a completion. The next time we took him
out he had some off steps on the left. Then it disappeared and it
reappeared and it tormented us. I finally took him out and rode him
until he developed a limp, threw him in the trailer and was able to land
him at the vet while he was still off so the vet believed me. We did
tests and discovered a slight suspensory pull high on the left. Off for
the season.
 Next year, after being cleared for riding from the vet we took off
again. Oh, and just to be defensive before I get flamed for racing this
poor animal over hill and dale, I was extremely conservative and careful
about bringing him back each year. This time he seemed to go strong and
sound for three rides. Then he had a mysterious tumble, came out of it
sound and three weeks later developed some sort of head scratching
slight lameness in his right pastern. Nobody could find a cause.
This winter, after being retired since September he suddenly came up
lame in the back. It looked like he got kicked or cut so I shaved the
leg...no cuts. Put on lineament and bandage and he seemed to heal up.
Took off the bandage and he got much worse. This went on for too long
(due to grandchildren being born, etc.) I put a bandage on, he got
better, take it off he got worse.
Today x-rays revealed a fractured sesamoid bone and pretty much
destroyed rear suspensory. Vet thinks he probably turned and tore it in
pasture in the slick mud.
QUESTION: Do some horses, like some humans, have a metabolic weakness in
their ligaments and tendons? Could that tendency be aggravated or caused
by diet (I don't know his early diet)? Shahin is carrying good weight,
has a bright eye and shiny coat and his stools are normal. ...in other
words no evidence to the eye of a metabolic imbalance. Did I miss
something some where or did Shahin just get dealt a short hand by his
DNA?

Terry C Roselle