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By Dr John.B.Walker B.VSc

Never has the saying 'Prevention is better than cure' been more appropriate than when talking about soundness in sport horses. 

Time and again we see good horses worth thousands of dollars have their careers limited or cut short due to preventable soundness issues.  The most common culprit is degenerative joint disease (DJD) or osteoarthritis.

DJD develops because the inflammation that occurs within the joint, as a result of galloping, jumping and work in general, gets out of control. Certain enzymes are then released which degrade cartilage.

The cartilage becomes soft and can easily become torn, which then exposes the underlying bone. Further inflammation and pain (and loss of performance) are the end result. 

The process accelerates beyond the ability of the body to repair the damage, unless we intervene with an appropriate supplement. Clinical symptoms include lameness, swelling, excessive synovial fluid, pain on flexion, and heat. DJD can range from mild to very severe but even mild cases will have a negative impact on performance. 

The traditional treatments for DJD include surgery, anti-inflammatorys, physical therapies and intra-articular medications including IRAP, sodium hyaluronate, and corticosteroids. A crucial step in the prevention and treatment of DJD is the use of oral nutraceuticals. 

If used as a treatment the evidence shows that a correct oral dosage needs to deliver at least 10,000mg of glycosaminoglycans (Glucosamine & Chondroitin).  

Consequently, a high quality joint powder concentrate like Shark Net or Cosequin is recommended.  My personal preference is Shark Net because it also includes adequate levels of Methylsulfonylmethane (MSM). 

MSM is an excellent dietary source of Sulphur, an element that is important in the formation of connective tissue and is credited with enhancing blood circulation and reducing inflammation and epiphysitis.  Please note that AR 178 C (2) allows the oral administration of Glucosamine and Chondroitin Sulphate.

In my experience one of the greatest benefits of these daily oral treatments is their long term preventative function.  On a maintenance dose they are a very low cost way of keeping the cartilage matrix healthy and helping prevent the onset of osteoarthritis.   

This doesn’t just apply to older working horses.  We now see the leading thoroughbred studs’ like Arrowfield using oral joint treatments as a prophylactic on yearlings to help insure they reach both the sales and the race track in the best possible physical condition. I know Arrowfield uses Shark Net Joint Powder Concentrate on both their racing and yearling stock.

The message for riders, trainers and owners is that our sport does take its toll on the horse’s joints and it is our responsibility to do what we can to limit the damage.   

The best time to start treating sport horses with oral glycosaminoglycans, is as young horses, because prevention is much better (and cheaper) than cure! See it as a financial investment if you like.  Should clinical signs of DJD become apparent a detailed veterinary examination is needed to determine the appropriate therapy.

Dr John B. Walker BVSc has more than 15 years experience working with some of the best horses in the country, from Olympic gold medallists to Australian Champion racehorses like Makybe Diva and Miss Andretti.  Having worked alongside vets such as Denis Golding,  Angus Mckinnon and Jim Vasey, Dr Walker now heads up Performance Equine Veterinarians, a specialist multi vet equine practice that services many leading trainers and equestrians.  He is also an FEI vet and consults extensively both interstate and overseas. 


Article reproduced with permission of Inside Racing magazine

COSEQUIN® is a registered trademark of Nutramax Laboratories®  Shark Net Joint Powder Concentrate is a registered product of Equine Health Science®

By Dr Christine King BVSc, MACVSc, MVetClinStud

What is lameness? An abnormality of gait that is caused by pain and / or restriction of movement.

The most common causes of lameness.

The basic processes that cause disease can be remembered by using the acronym DAMNIT:

D: degenerative, developmental
A: allergic, autoimmune 
M: metabolic, mechanical
N: neoplastic (tumors), nutritional
I: infectious, inflammatory, immune-mediated, ischemic (low blood flow), iatrogenic (man-made), idiopathic (unknown)
T: traumatic, toxic

Most causes of lameness fall into the following categories:

  • Degenerative e.g. degenerative joint disease (DJD, or osteoarthritis)

  • developmental e.g. osteochondrosis (OCD), physitis (epiphysitis)

  • metabolic e.g. laminitis (founder), exertional rhabdomyolysis (tying up)

  • mechanical i.e. overload of a structure - either sudden, massive overload or repeated, marginal overload (wear & tear)

  • infectious e.g. foot abscess, infected wound, cellulitis, joint infection

  • inflammatory - most of the specific causes of lameness have an inflammatory component

  • traumatic i.e. injury (external trauma)


Identifying the location of the problem - Which leg?

Observation is the key to identifying which is the lame leg:

  • Abnormal stance-e.g. pointing the toe, resting one leg more than another, dropped fetlock

  • Abnormal movement-head nod (forelimb lameness), hip hike (hindlimb lameness)

  • Reduced arc of foot flight-often seen as stiffness or reluctance to flex the limb normally

  • Shortened stride length-shortened 'swing' phase of the stride

  • Abnormal foot placement-e.g. landing toe-first to spare the heel


Evaluate the horse's gait:

  • on a level, even surface

  • at the walk and the trot

  • in a straight line and in a circle (led, lunged, or in a round pen)
    - make sure the horse is on a loose lead or lunge line
    - watch the horse in both directions on the circle

  • from the side, in front, and the rear

  • on different surfaces (e.g. hard and soft)


Bear in mind that there may be a problem in more than one leg.

Investigating the cause: Basic Skills

Locating the specific area involved requires two basic tools: your eyes and your hands.

The three skills required are Observation, Palpation, and Manipulation.


  • look for symmetry between left and right legs, and between the inside and outside of a normally symmetrical structure

  • when asymmetry is found, is it caused by enlargement (e.g. swelling) or reduction in tissue mass?



  • feel for heat, swelling, pain, and changes in tone or texture of a tissue

  • characterize any swellings as hard, firm, soft, fluid-filled



  • move the structure or tissue through its normal range of motion

  • check for pain, altered range of motion (increase or decrease), and crepitus (a grating, grinding, or crackling sensation)


Use these skills to identify the five basic signs of inflammation:

  • Pain

  • Heat

  • Swelling

  • Redness

  • Loss of function


Investigating specific areas

Tailor your investigation to the structure you are evaluating:

The Foot - the most common site of lameness.

  • Observation - symmetry of the hoof wall; integrity of the hoof wall (cracks, bulges, etc.) and sole (defects, foreign objects, etc.); discharge, discoloration, or odor; shoe and nails

  • Palpation - coronary band (pain, swellings, depressions); heel bulbs; sole (thumb pressure); digital pulses (at fetlock or pastern)

  • Manipulation - move the heels independently; tap the hoof wall; use hoof testers (if you have them)



  • Observation - swelling, position (angulation)

  • Palpation - nature of the swelling, heat, pain

  • Manipulation - flex (bend) and extend (straighten) the joint, checking for pain and altered range of motion



  • Observation - swelling

  • Palpation - nature of the swelling, heat, pain

  • Manipulation - pain, instability, crepitus


Tendons and Ligaments

  • Observation - swelling

  • Palpation - swelling (subtle swelling may not be obvious to the eye), location of the swelling (within or around the structure?), heat, pain, change in tension and texture - if possible, also palpate the sites where the structure attaches to bone

  • Manipulation - pain, instability of the associated joint



  • Observation - swellings or atrophy (loss of muscle mass)

  • Palpation - pain, change in tone and texture, crepitus, heat or coolness

  • Manipulation - pain, reduced range of motion in the associated joint(s)


Neck and BackThe neck and back consist of a complex series of bones, joints, tendons, ligaments, and muscles:

  • Observation - symmetry, posture, contour

  • Palpation - nature of any swellings, pain, change in muscle tone and texture

  • Manipulation - pain, reluctance to flex or extend, reduced range of motion

Other possible sources of lameness

Also consider these other possible sources of lameness:

  • the skin

  • the nervous system (brain, spinal cord, nerves)

  • the tack (especially the saddle)

  • the rider (bridle lameness or rein lameness)


Interpreting your findings:

1. The pain response must be repeatable to be valid.
- when you return to the suspect area you should get the same (or greater) response to palpation or manipulation each time
- the pain response may be subtle (e.g. tensing up, turning the head to look at you, moving away from your hand), but if it is repeatable, it is probably significant

2. Assuming the opposite leg is normal, use it for comparison if unsure that your findings are significant.

3. Most lameness problems involve a structure in or below the knee or hock.

4. A specific diagnosis often is not possible without veterinary examination and diagnostic imaging.Veterinary Examination

Veterinary Surgeons use the following procedures to evaluate lameness and determine the cause:

  • physical examination (observation, palpation, manipulation)

  • gait evaluation

  • joint flexion tests

  • diagnostic anesthesia 
    - regional nerve blocks and joint blocks

  • diagnostic imaging 
    - the method chosen depends on the veterinarian's suspicions
    - radiography (x-rays) - bones and joints
    - ultrasonography - soft-tissue problems, such as tendon and ligament injuries, and joint surfaces
    - thermography - body surface temperature imaging, looking for areas of inflammation (increased temp.) or reduced blood flow (decreased temp.)
    - nuclear scintigraphy (bone scan) - soft-tissue phase for soft-tissue inflammation; bone phase for bone or joint problems
    - computerized tomography (CT) - any tissue, but mostly used for bone problems
    - magnetic resonance imaging (MRI) - mostly soft tissues and joint surfaces

  • therapeutic trial - presumptive diagnosis based on response to treatment

Dr. Christine King © 2001 BVSc, MACVSc, MVetClinStud

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