Equine Suspensory Apparatus Dysfunction
in the form of
Degenerative Suspensory Ligament Desmitis
What is DSLD?
Degenerative Suspensory Ligament Desmitis is a syndrome; a degenerative
bilateral condition whereby there is inflammation and faulty healing of the
suspensory ligament, resulting in typical thickening or hardening of the
mid-body of the ligament or the suspensory branches resulting in loss of
integrity of the suspensory ligament and its ability to do its intended job of
supporting the horse.
What causes DSLD?
There is speculation that the horse develops an abnormal response to normal
stresses on their suspensory ligaments by failing to "manufacture"
new collagen for repairing tiny tears and strains. Instead of new collagen
fibres being laid down in line with the stesses on the ligaments, cartilage is
laid down in the suspensories resulting in loss of tissue strength or
elasticity. Without the ability to stretch, even normal weight-bearing on the
limbs can become too much, and over time, the ligements lengthen and break
down. It is important to remember that no matter how the injury or stress
occurs, DSLD cases improperly heal the ligament injury with cartilage instead
What symptoms will a horse with DSLD
Generally a bi-lateral (both front legs or both hind legs) lameness, although
the severity of the lameness varies among horses and may go undetected in some
until the condition becomes fairly well advanced. There is generally painful
response to palpation of the branches of the suspensory ligement, particularly
in the area where the ligament branches. In more advanced stages the fetlocks
seem to be sinking more when the horse moves. As the condition worsens, the
pastern area becomes increasingly parallel to the ground, and ringbone can
develop. In later stages, one of the most telltale signs of DSLD is in the
horse affected in the hind legs; the pasterns level out making the fetlocks
appear dropped and the stifle and hock gradually straighten, making the horse
reticent to move even to its feed or water. Some horses will dig a hole in
their stall or paddock and stand with their toes pointing down and the heels
elevated. On hard surfaces, horses may rock back and forth, relieving one leg
and then the other. Some horses find the condition painful enough to spend a
more than normal amount of time lying down.
How is DSLD diagnosed?
Palpation of the suspensory ligaments reveal bilateral pain response and
thickening or hardening of the mid-body or branches. Ultrasound imaging will
show poor fiber pattern at the origin of the suspensory or at the bifurcation
and branches. The branches' circumference might be enlarged bilaterally. In
radiographs, the sesamoid bones will be lower than normal in relation to the
fetlock joint, with possible bilateral mineralization of the suspensory
branches visible. Degenerative joint disease might be visible in the pastern
joint; subluxation of the pastern joint will worsen. Themography will show
significant bilateral warming over the branches of the suspensory. Nuclear
scintigraphy in both the soft tissue phases will show the suspensory branches
as quite reactive; in the bone phase, the proximal sesamoid bones and pastern
joint will "light up."
What breeds of horses are
DSLD has been diagnosed in the following breeds: Arabian, American Saddlebred,
National Show Horse, Paso Fino, Peruvian Paso, Quarter Horse.
Is there a genetic link?
Though DSLD has been diagnosed in several breeds, early findings are that it
seems to be more prevalent in certain bloodlines within those breeds. In spite
of these early findings, there are some who speculate that DSLD is related to
mismanagement and improper care. Others feel it is related to poor
conformation. So far, attempts to find a genetic marker have been met with
resistance from breeders unwilling to cooperate with full disclosure of
affected animals pedigrees or lists of related affected animals, so little
progress has been made on that front. So for now, this question remains
My horse was diagnosed with DSLD; What do I do
First, be sure that the diagnosis has been determined by a qualified
veterinarian. There are a number of different types of leg problems--more
specifically suspensory problems--that may at first look appear to be DSLD.
Once certain that indeed your horse has DSLD, much depends on how advanced the
condition is. There has been success in a number of cases with the addition of
methyl sulfonyl methane (MSM) and other supplemental aids to the diet, using
shoeing techniques that raise the heels of the hooves on the affected legs to
relieve pressure on the suspensories, and the use of stall rest followed by
DSLD and Dietary Supplementation). With early diagnosis and working closely
with your veterinarian, many horses have the chance of returning to some riding
and many more are able to be kept pasture-sound.
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