LAMENESSES, LIGAMENTS,
BONES & TENDONS
By Dr Jennifer H Stewart BVSc BSc PhD MRCVS AAIM Dip BEP
Equine Veterinarian and Consultant Nutritionist
Quarter Horses used for western performance and stock horse
events can sustain a variety of musculoskeletal injuries. Risk
factors vary, but the common features include work at high
speed, abrupt stops and changes of direction, and rapid high
torque turns. Smaller horses, with lighter cannons may have a
competitive advantage in events that require quick movements
of the limbs, such as in the rapid sweep of the cutting horse or
the spin of the reining horse. However, small young horses with
lighter limbs and bone density are at increased risk for acute
injuries and developmental problems.
canter rather than trot – especially at faster paces. Any bone
may be affected and temporary healing may explain the
shifting lameness.
Musculoskeletal problems often present as decreased performance and/or behavioural problems – such as resistance to
entering the starting pen or arena, reluctance to stop or turn
hard, not ‘holding the cow’, not ‘getting into the ground’, or
‘dropping leads’. This is because the lameness may be difficult
to detect, affects one of more legs, there may be more than one
problem, it may be difficult to observe lameness in short, highspeed events, or the footing may be soft and the lameness less
obvious than on a hard surface.
Affected animals can only be treated by correcting the imbalance of calcium and phosphorous. Added magnesium and
salt increases calcium absorption from the supplement – which
should contain chelated calcium, phosphorus, and essential
trace and micro-minerals, which are deficient in Australian
soils and pastures. Sources of calcium for inclusion in drinking
water do not fulfil these criteria, and once-weekly supplements
have a mineral retention of only 35 per cent. Increasing
the frequency of supplementation or extending the time of
consumption is more efficient than increasing the dose.
Suspensory ligament problems in competitive rodeo, stock and
barrel racing horses can be caused by overgrown feet or poor
foot conformation and suboptimal surfaces such as deep sand
or mud. Shock wave therapy and 30 days stall rest with handwalking is recommended for mild cases, others may require 6
to 12 months off and a graded exercise program. Hock spavin
is common in cutting and reining horses, and stifle lameness
in roping horses. Back pain in young reining and cutting
horses in hard work, most often arises secondary to front or
hind limb pain.
Osteoporosis is a silent danger for all horses because – as in
humans – reductions in bone density are difficult to diagnose.
Signs include intermittent shifting lameness due to tearing of
the bone surface, torn or detached ligaments and tendons, or
microfractures. Joint pain results from loss of underlying bone.
Lameness is usually insidious with general joint pain, a stiff,
stilted gait; mild shortening of stride, and a preference to
Osteoporosis is caused by calcium deficiency and is widely
recognized in horses grazing buffel, pangola, setaria, kikuyu,
green panic, guinea, signal and purple pigeon grasses. These
grasses contain oxalates, which bind to calcium, and prevent
uptake and absorption. The time of onset after grazing highoxalate pasture is two to nine months.
In addition, free oxalate in the grass can bind the supplemented calcium in the small intestine. Some manufacturers recommend removing horses from pasture for an hour before and
after feeding their supplement; this attempts to minimise the
chance of the oxalates in the pasture binding to the calcium in
the supplement. Chelated calcium is protected from oxalates
and over 95 per cent absorbed. Dr Jennifer Stewarts Bone
Formula contains chelated calcium and through extensive
research the correct formula has been created to fulfil this
requirement.
Proper exercise and nutrition are central to reducing the
risks of lameness. Correct calcium intake and sufficient
pasture exercise early in life are essential for young horses.
The importance of good nutrition, proper hoof trimming and
shoeing cannot be overemphasised for reducing lamenesses,
and tendon, bone and ligament injuries – and to protect
soundness at all ages.
“These images show how the teeth fail to meet and the jaw fails to close properly due to osteoporosis in the skull – making it harder to bite mouthfuls of pasture. Once the skull is
affected, all bones in the skeleton are osteoporotic.” Photos: Dr Oliver Liyou BVSc (Hons) MACVSc ︱ Equine Veterinary & Dental Services ︱ 51 Duncans Lane, Clarenza, via South Grafton
PO Box 95, South Grafton NSW 2460 ︱ Phone: 02 66 424 700 ︱ Fax: 02 66 428 564
Page 66 • The Australian Quarter Horse Magazine • November • December 2015