Arabische Pferde IN THE FOCUS Nr. 2/2019 - Preview

Fatigue damage in the fetlock of a racehorse is similar to fatigue damage in other materials such
as metal. - Ermüdungsschäden im Fesselgelenk eines Rennpferdes ähneln den Ermüdungsschäden
in anderen Materialien wie Metall.
should be avoided during this period.
As we refine these models we will trial variations
of training intensity to better mirror actual
racehorse training programs so that we
can make more specific recommendations.
In the meantime trainers need to be cautious
in returning horses to work too rapidly if they
have been rested from training for longer
than a week.
The Importance of Rest Periods
Race horses need periods of time away from
the rigours of racing and race training to
stay at their peak. Spells from racing are
essential to maintain bone and joint health
because when horses are racing at their
peak, bone repair is inhibited and so bone
damage accumulates. However during rest
periods the bone repair processes are activated
allowing removal of damaged bone
and replacement with new bone. Periods of
rest from training are therefore essential to
prolong the career of race horses.
The obvious question then is how much
training is too much and how much rest is
needed to maintain bone damage at safe
levels. As with all biological questions this
is difficult to answer for a particular horse
because of the large variation between individual
animals. However, based on the high
incidence of joint injury in race horses it is
reasonable to assume that most horses are
not getting enough time away from training
to allow adequate bone repair.
Although the racing calendar makes it difficult
to increase time off training, finding an
extra few weeks in the paddock each year for
rest and recovery will mean fewer injuries
that could have forced an unplanned rest or
even retirement.
Rest Periods for Joint Injury
Veterinarians commonly recommend rest
periods for horses with injuries or lameness
problems. This can be challenging for owners
and trainers to accept due to the expense
of keeping horses during rest periods and
training when they are not earning money
on the track. So it’s important to understand
the purpose of rest.
For joint injuries the goal is to allow the
bone underlying the cartilage to heal and
for inflammation to subside. Provided there
is no ongoing irritation or damage, soft tissue
inflammation settles in about six weeks.
For bone, the traditional three month healing
period is based on data from experimental
animals. However in our studies on
the horse, after three months only 16% of
the bone under cartilage will be replaced
suggesting that much longer periods of rest
might be necessary. We have also seen that
when microscopic damage is extensive the
healing cells are unable to gain access to
the injured area and this further delays the
healing time.
Failing to allow adequate time for a joint injury
to repair will result in greater stress on
the remaining healthy joint surface and an
increased risk of arthritis and pain developing.
Horses’ joints routinely experience extreme
loads when galloping so there is little
scope for the uninjured portion of a joint
surface to cope with greater loads. That’s
why horses with joint injury fail to perform
to expectations for the remainder of their
careers. The short term gain of getting a horse
back to racing earlier after an injury may
be offset by substandard performance and a
shortened career.
So in summary injury prevention in racehorses
involves:
• Allowing time for the skeleton to adapt
to galloping when training is first introduced
or when it is reintroduced after a
rest period.
• Minimising the accumulation of bone
damage by avoiding intense training and
racing campaigns. This can be achieved
by reducing the distance of galloping
workouts and spacing races by three to
four weeks.
• Scheduling regular spells from intense
training.
• If injury does occur follow your veterinarian’s
recommendations on the appropriate
period of rest from training, and
ensure that the preparation for return to
racing is gradual.
Dr R Chris Whitton,BVSc, PhD, FACVSc
Head of the Equine Centre, Professor of
Equine Medicine and Surgery, Specialist
in Equine Surgery, The University of
Melbourne, Australia
The number of cycles of load to failure: The higher the speed (the faster) the earlier bone fatigue
may occur (fewer strides). - Die Anzahl der Belastungszyklen bis zum Versagen: Je höher die
Geschwindigkeit, desto früher kann eine Knochenermüdung auftreten.
Science
2/2019 - www.in-the-focus.com
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