The Official Veterinary Examination
The Club invests considerable time and energy in assessing the veterinary suitability of horses to compete in races. The objective of these assessments is to protect horse and rider safety, to provide for the welfare of racehorses and to assist in maintaining consistent racing performances.
The following information is provided to help customers better understand the procedures by which the Hong Kong Jockey Club attempts to manage the suitability of horses to race.
A brief description of some of the veterinary problems that commonly result in horses being issued with Official Veterinary Examinations (OVEs) is also provided. The descriptions and explanations are necessarily brief; however, interested readers are suggested to follow the links provided to obtain more detailed information.
1. When is an Official Veterinary Examination requirement issued to a racehorse?
An Official Veterinary Examination (OVE) is issued by the Chief Stipendiary Steward or Regulatory Veterinary Officer whenever;
A horse returns an unacceptable racing performance that may have been attributable to a veterinary problem.
A significant veterinary problem is identified during the examination of a horse sent for a clinical examination after racing.
The Veterinary Regulation Department is advised by the Veterinary Clinical Department of the diagnosis of a significant injury or medical condition in a horse.
2. Why are Official Veterinary Examination requirements issued?
OVEs are issued to, as far as possible, ensure that;
Unacceptable racing performances are investigated so that any veterinary problem that may have contributed to a poor racing performance may be identified and treated, if possible.
A horse identified as suffering from a condition that may impact on its racing performance, health or welfare has that condition investigated, treated and that the horse demonstrates its suitability to race to the satisfaction of an Officer of the Veterinary Regulation Department.
3. What is the procedure for conducting an OVE?
Once the trainer has been notified that a horse under his care has been issued with an OVE requirement, he will arrange a clinical examination of the horse by his stable veterinary surgeon.
On completion of the examination, the trainer and stable veterinary surgeon will work out a management plan for the horse.
When the trainer and his veterinary surgeon are satisfied that the horse is in a suitable condition to return to racing, the trainer will arrange for the horse to undergo the OVE.
An Officer of the Veterinary Regulation Department will review the treatment records and inspect the horse on the day prior to the test to confirm that it is in a suitable condition to undertake the test.
On the day of the test, the Officer will observe the horse during a gallop or barrier trial and then re-examine it approximately an hour after the gallop to ensure that the horse has pulled up well from exercise.
If the horse passes the OVE it may enter to race again. If it fails the examination, it will be referred back to the trainer and stable veterinary surgeon for further investigation.
Relatively minor injuries and illness may require a 'no gallop' OVE or 'To Watch' examination, which usually involve only a clinical examination by an Officer of the Veterinary Regulation Department prior to entering to race again.
COMMON VETERINARY CONDITIONS THAT MAY BE MENTIONED IN RACING INCIDENT REPORTS
There are a number of terms used to describe lameness. These usually reflect the severity and nature of the lameness.
'Not striding out freely'; a term often used by jockeys to describe a horse that is uncomfortable and restricted in its action. It usually indicates a low-grade lameness that is apparent under the pressure of galloping, but may not be apparent whilst trotting.
'Scratchy Action'; a term often used by jockeys to describe a horse that is stiff and uneven in its action. Similar to 'not striding out freely', but may imply more of a stiffness and lack of fluidity in a horse's action.
'Stiff'; refers to a fairly generalized lack of ease and fluidity in a horses' movement. It is often associated with muscle soreness or generalized arthritic changes in older horses.
'Jarred Up'; refers to the joint pain and inflammation experienced by horses after galloping, most often affecting the front fetlock joints. The problem may resolve in a few days with appropriate rest and treatment or may be sign of the onset of osteoarthritis of the joint(s).
Lame; a generally used when the horse is obviously favouring a leg and often implies a more significant injury or effect on performance than the descriptions given above.
Inflammation; the process by which the body responds to injury and considered an essential part of healing. The signs of inflammation are heat, pain, swelling, redness and loss of function. Sometimes the body may over-react to injury to the extent that the inflammatory process causes further tissue damage. In such cases, anti-inflammatory treatment may be required to 'normalize' the inflamed structure.
The application of the suffix 'itis' to the name of a structure indicates inflammation of that structure. For example, carpitis is inflammation of a horse's carpus (the knee), tendonitis is inflammation of a tendon, sesamoiditis is inflammation of a sesamoid bone, etc.
The following abbreviations may be used to designate the affected leg in OVE reports.
Occasionally, a horse will be reported simply as lame. This most often occurs when a horse has been examined after a race and has been found to be lame without a specific diagnosis.
These horses will be referred to the stable veterinary surgeon for a comprehensive lameness examination and, if a diagnosis is made, the OVE report will be updated to provide more information.
Tendon Injuries (Tendonitis)
Tendons are strong cord like structures that transmit the pull created by a contracting muscle to bones to produce movement. They are composed of collagen and elastin fibres and are very strong, but have only limited elasticity or stretch.
Tendons in the horses' legs are subject to tremendous forces. They have a relatively poor blood supply and when injured, heal very slowly by the formation of scar tissue. Scar tissue has virtually no elasticity. This means that an injured tendon is very prone to re-injury under the stresses of full training and racing.
The tendons most commonly injured in the racehorse are the superficial digital flexor tendons (SDFT) of the forelimb. These tendons run down the back of each cannon and transmit the pull of the muscle behind the forearm to the bones of the foot.
Getting a horse back to racing after a tendon injury requires a great deal of skill and hard work. Often a serious tendon injury will result in the retirement of a horse from racing.
Suspensory Ligament Injuries (Suspensory Desmitis)
Ligaments are strong bands of tissue that bind bones together and stabilize joints.
The suspensory ligament runs from the top of the back of the cannon bone over the back of the fetlock joint and inserts on the sesamoid bones before joining the extensor tendon towards the front of the pastern region.
It is a very strong, relatively elastic structure that plays an important role in supporting the fetlock joint as it sinks to the ground when a horse's weight passes over the forelimb during motion. It is subject to tremendous forces during galloping, especially when the muscles fatigue.
When injured, the suspensory ligament also heals with scar tissue and once damaged, it is prone to re-injury. Depending on the severity, suspensory ligament injuries may have severe consequences for a horse's future racing career. Seventy percent of all racetrack breakdown injuries are the result of failure of the suspensory apparatus (which comprises of the suspensory ligament, the sesamoid bones and other vital soft tissue structures in the limb).
Joints are the structures that allow movement where bones meet bones. For our purposes, the most important type of joints are synovial joints. These joints have a joint capsule that surrounds the space between the bones that is lined by synovial membrane, which produces lubricating and shock absorbing synovial fluid. The ends of the bone within the joint are covered by very smooth cartilage. The smooth cartilage joint surface together with the lubricating joint fluid, permit virtually frictionless movement of the bones over each other.
Racehorses' joints are subject to tremendous stress and 'wear and tear'. These stresses may result in inflammation of the joint capsule, degradation of the lubricating synovial fluid, cartilage damage, possible chip fractures and, without careful management, may progress to incurable osteoathritis.
Mild joint stress may be described as 'jarring up'.
Degenerative joint disease and osteoarthritis are terms used to describe more advanced joint diseases.
The fetlocks, knees and hocks are most commonly affected by osteoarthritis, although any joint may become arthritic. The development of osteoarthritis is one of the most common reasons that horses are retired from racing.
As in humans, back pain is a common cause of chronic pain and loss of athletic performance in horses. The causes of back pain range from simple overuse muscle soreness to ligamentous strain to osteoarthritis to spinal nerve root impingement.
Back pain often results in a stiff, restricted hindlimb action.
Nuclear Scintigraphy and 'Hot Spots'
Horses may suffer stress fractures of bones in the same way the human athletes are affected. Unfortunately, horses cannot tell us where they are sore and, because of their size, it is often difficult to get diagnostic X-rays of areas surrounded by large masses of muscle, for example the pelvis. Also, actively remodeling bone tissue may be very painful, but not show signs visible on X-ray until the changes are well advanced.
Nuclear scintigraphy involves the injection of a radioactive substance (a radio-pharmaceutical) into the horse that travels via the bloodstream to localize in areas of increased bone tissue activity, for example where the body is attempting to repair a stress fracture or where it is attempting to adapt and model to new stresses.
A gamma camera measures the uptake of the radioactive pharamaceutical and a computer produces an image of a horse's skeleton identifying the area of increased bone activity. These areas of reactive bone are referred to as 'areas of increased of radio-pharmaceutical uptake (RPU)' or 'hot spots'.
Hot spots are often indicative of hairline stress fractures that may require three to four months rest from training to allow healing to occur.
Respiratory disorders are a common cause of poor racing performance and affect performance by reducing a horse's oxygen intake.
Mucus and Mucopus
A relatively common post-race finding in a horse sent for clinical examination after returning a disappointing racing performance is 'a significant quantity of mucus or mucopus' in the trachea (windpipe).
The use of an endoscope (a device with a light attached used to look inside a body cavity or organ) allows for direct visualisation of a horse's upper airways and visualisation of inflammatory exudates.
Mucus is important for normal airway health íV it traps inhaled materials and pathogens such as bacteria and also contains a number of immune factors that help to protect against disease. The quantity of mucus is dependent on the balance between mucus production and its clearance.
The respiratory clearance mechanisms in a healthy horse is extremely efficient, meaning that mucus elimination usually keeps pace with production and secretion.
No mucus or minimal amounts of mucus (a few droplets) is considered normal. With airway inflammation or irritation, mucus production increases and results in the accumulation of mucus in the airways, this may have an effect on, or be indicative of conditions that may have an effect on, performance.
Mucopus is a mixture of mucus and pus that appears during infection or inflammation of the airways. A common name for mucopus is phlegm. The presence of mucopus indicates that the horse is suffering from a respiratory infection that might prevent it from performing up to expectation due to compromised gas exchange.
Detection of mucopus post-race after a disappointing performance often raises the question 'why was the problem not detected earlier and why was the horse permitted to race?' The answer is that although the infection may be significant in terms of athletic performance, the outward signs are often very mild and may not be detectable without an endoscopic examination of the airways after racing.
Bleeding (Exercise Induced Pulmonary Haemorrhage Syndrome)
Bleeding results from the rupture of capillaries in the lung tissue that permits the escape of blood into the air sacs (alveoli) where the exchange of gases takes place.
The blood vessel and alveolar walls are thought to rupture because of the high pressures on one side of the barrier (in the blood vessels) relative to the low pressures on the other side of the barrier (in the airspaces or alveoli). There is still some debate, however, about how this actually happens.
Horse lungs are designed for extremely high performance exchange of gases to support strenuous exercise. In the same way that a Formula One racing car design pushes the limits of safety and durability to achieve optimum performance, the horses' cardiopulmonary system sacrifices some durability and strength for a comparable level of biological performance.
Most horses bleed from the lungs to some extent after strenuous exercise and post-race surveys have shown that around 40% to 90% of horses show some blood in their airways after racing.
The majority of horses that bleed don't show any outward signs of bleeding, such as blood at the nostrils. Such bleeding may only be detected by endoscopic examination and may, or may not, affect racing performance.
In a few cases, horses bleed to the extent that blood appears at their nostril(s). Under the Hong Kong Jockey Club Rules of Racing, such horses are declared to be 'official bleeders' and will be banned from racing for three months. If a horse officially bleeds from the nostril(s) on three occasions, it will be compulsorily retired from racing.
If blood is detected in the airways during the post-race examination of a horse sent for clinical examination, the examining veterinarian will make a subjective decision on whether the severity of the bleeding into the airways could likely be expected to have affected a horse's performance and if so, this will be reported as 'a significant quantity of blood detected in the horse's trachea on post-race endoscopic examination' and an OVE requirement will be issued.
Horses that have bled in the past are more likely to bleed again in the future.
"Roarers" (Laryngeal Hemiplegia)
The term 'roarer' comes from the roaring sound that these horses can make when breathing heavily during galloping as a result of dysfunction of the larynx. Commonly referred to as the 'voice box' in people, the larynx is involved in breathing, sound production and in protecting the trachea (and lungs) against food aspiration.
Laryngeal hemiplegia is a condition in which a muscle responsible for abducting (opening up) a flap of cartilage that closes to guard the entrance to the airway during swallowing, but opens during breathing to allow the free flow of air into the lungs, becomes progressively paralysed because of nerve degeneration.
The paralysed muscle is unable to lift the flap of cartilage up and out of the entrance to the airway during inspiration and it is left 'flapping in the wind' as the horse breathes in. This flapping causes vibration, turbulent airflow and the characteristic 'roaring' sound.
The presence of the flap of cartilage in the entrance to the airway significantly reduces the intake of air to the lungs and compromises athletic performance.
The course of the degeneration of the nerve that supplies the muscle involved is very unpredictable. The condition may be mild and progress very slowly and the horse may perform acceptably, especially over shorter distances, because the intake of air is only mildly compromised. Or in other cases, the condition may progress very rapidly and an apparently normal horse may suddenly return a disappointing racing performance and show signs of advanced laryngeal paralysis.
Surgical treatment of the condition is possible whereby a permanent suture is positioned to perform the function of the wasted muscle. This procedure is called a laryngoplasty or 'tie-back'.
The procedure is relatively successful in restoring airway function during strenuous exercise and often horses returning to racing after surgery show significantly improved racing performance. Despite this however, some horses do not improve because they have learned to associate racing with partial suffocation caused by the laryngeal paralysis and are reluctant to race at maximum intensity.
Soft Palate Conditions
The palate (hard and soft palate) separates the cavities of the mouth and nose. The soft palate is a flap of soft tissue that extends backwards into the horses' throat from the hard palate. Unlike many other animals including humans, horses are obligate nasal breathers. Normally, the soft palate forms an airtight seal that closes the mouth from the airway and allows a smooth flow of air into the lungs from the nose during breathing.
In some horses, this seal may be ineffective and the soft palate may displace upwards from its normal position (termed Dorsal Displacement of the Soft Palate) and interfere with breathing.
Jockeys often report that the horse slowed suddenly in running and made a gurgling noise or that the horse 'choked down' during the race. The problem can be frustrating to diagnose because the horse can re-position the soft palate by swallowing and often by the time the horse has returned after racing, everything appears in its normal anatomical position.
The problem may be managed by the use of a tongue-tie and a cross over noseband. In cases that do not respond to conservative treatment, surgical correction may be attempted.
The epiglottis is a triangular flap of cartilage that functions to prevent food and water from entering the larynx and trachea during swallowing. In some horses, a fold of membrane on the floor of the throat may entrap the epiglottis. When the horse breathes out forcibly during strenuous exercise the membrane balloons up like a sail and obstructs the outflow of air from the lungs.
Surgical treatment of the condition is usually successful.
Any dysfunction of the heart will reduce the volume of blood pumped around the body and reduce oxygen supply to exercising muscles.
The most common heart irregularities seen in racehorses are arrhythmias, which literally mean no rhythm to the heartbeat. The most common type of arrhythmia that causes poor performance in racehorses is Atrial Fibrillation (AF). Often the only sign of the condition is a poor racing performance.
All horses that undergo a veterinary clinical examination after racing are checked for heart irregularities by auscultation and, if necessary, Electrocardiograph (ECG) examination. Horses undergoing an OVE for a heart irregularity have to show a normal ECG during and/or after the OVE gallop test.
Racehorses are subject to intense physical stress during training and racing. Stress may cause immunosuppression and can cause horses to be more susceptible to infections. Often the signs of infection are mild and difficult to detect. Slight dullness, a minor increase in body temperature and a decreased appetite may give some indications of underlying illness. Blood tests can also prove useful in the detection of early infection.
Although the signs are mild and affected horses may not appear to be obviously sick, the presence of an infection can have a significant effect on racing performance, where horses have to be in excellent health to perform competitively.
Horses found to have subclinical infections will be treated by the stable veterinary surgeon and rested. A blood test to ensure that the horse has recovered will be required as part of the OVE.
Horses will usually be issued with an OVE requirement after having had a surgical procedure performed on them.
The common surgeries performed at the HKJC include;
Arthroscopic Joint Surgery
Arthroscopic surgery is commonly used to remove chip fractures or damaged areas of cartilage from injured joints, especially the knee and fetlock joints.
The common throat conditions requiring surgical correction include laryngeal hemiplegia, Dorsal Displacement of the Soft Palate (DDSP) and epiglottic entrapment.
Colic is a common name for abdominal pain. Colic surgery in the horse often involves correcting intestinal twists and obstructions.