Image 1: Dr Tim Roberts inspecting off-fore
Examining horses routinely after gallops and before racing helps the prevention of serious injury. Early detection can prevent a more serious injury which can lead to a long rehabilitation or at worst, be career ending. It is also our responsibility, as veterinarians, to keep these racehorses sound for the safety of trackwork riders and jockeys.
Our veterinarians and the trainers, who trust us with caring for these horses, work together in ensuring that the horses are well cared for and routinely examined. Examining and understanding the soundness of a particular equine athlete, your horse, contributes to both improved soundness and optimises a horse’s ability to perform.
The soundness process starts with the selection of horses at sales. Although pedigree and environment play a large part in performance, it is hard to achieve a suitable performance level in poorly conformed horses. There are certain attributes to conformation that improve a horse’s ability to achieve at elite levels.
While not all horses are purchased through a sale ring, some are owner bred and raced. In these cases, pedigree and environment are the only aspects that can be controlled. While certain conformation anomalies may limit a horse’s longevity, it is important to manage such affected horses so that they remain as sound as possible, and in doing so are able to maximise their success on the racecourse.
Training techniques and available facilities such as swimming pools, treadmills and track variation play a major part in optimising longevity. However, ensuring soundness and preventing injury is just as important to achieve longevity of a racing career and to reach optimal performance.
On that note, let’s talk about trot-ups, gait and lameness and how this helps with the management of your horse as an elite athlete.
Trot-ups are a routine procedure where gait and movement are determined and evaluated. Our veterinarians watch the horse trot up and down a straight line while observing the horse’s movement. Individual horses have variations to their gait which the veterinarian will become familiar with and look for changes or unsoundness. Our team of experienced equine veterinarians can then flag any noticed irregularities early on with the trainer, to help manage the horse and prevent long-term damage. Lameness can develop gradually and can involve more than one limb.
The load on a horse’s skeleton increases as the gait and intensity of training increase. The actual impact forces of the galloping surfaces as well as the repetitive mechanical forces on insertions of the tendons, origins and insertions of ligaments, create stresses throughout a horse’s musculoskeletal system. Conformation has a direct correlation regarding these forces.
Image 2: Diagram of equine anatomy
The repeated load over limbs can result in tissue damage or bone stress injuries, also known as microfractures, overtime. The most susceptible bones to stress injuries are those high motion joints that bear the load, namely the fetlock and the knee (carpus).
Repeated loading of bones, joints and tendons causes deterioration in the structural integrity of these tissues. This process starts gradually and is accumulative however if identified early intervention can, in most circumstances, prevent permanent or catastrophic failure.
Image 3: Diagram of equine tendon (Medrego, 2020)
When it comes to bone injuries, stress fractures commonly occur deep in joints where radiographs are not capable of showing subtle bone changes. Radiographs however remain a very useful diagnostic tool and can confirm a bone injury however they do not eliminate the presence of an injury if no noticeable radiographic changes are present.
The best method of localising a bone or ligament injury is using intra articular or peripheral nerve blocks. If an area is identified and radiographs or ultrasound scans cannot identify the injury there are other imaging modalities.
Scintigraphy (Bone Scanning) - This useful diagnostic tool (using radio isotopes) has been available for nearly 20 years and remains a valuable means of detecting early bone injury, particularly stress fractures. Indications in racehorses may include an inability to localise the source of lameness or most commonly shadowing suspicion of a stress fracture. It is a sensitive imaging modality for assessing the osseous structures of the musculoskeletal system. This means that it will show an area of increased radio isotope marker uptake, its limitation is that it gives no detailed information regarding the pathological process in the identified location. Its advantages include its high sensitivity and being able to image all parts of the skeleton including upper limbs, the spine and pelvis. Disadvantages include relatively low resolution and the need to administer radiation which takes the horse out of training for 2-3 days.
MRI Standing - This modality allows detailed 3D imaging of bone and soft tissues in the lower limbs using magnetic impulses allows for great image resolution and detection of soft tissue detail and fluid accumulation (e.g. Inflammation).
CT Standing - This technique, the most recent innovation, is a form of cross-sectional imaging that uses x-rays to allow evaluation of an area of interest in multiple planes. It is useful to further characterise pathology already localised on lameness exam.
These different imaging modalities can help veterinarians understand the extent of the injury and therefore how much effect it is having on the performance of horses under their care. Early detection is critical for many injuries, particularly those of joints, enabling veterinarians to determine better options for early management and treatment, as once they become advanced the effect on performance may be permanent.
Soundness and prize money
While soundness does have a direct correlation to prize money it does not necessarily mean improved ability. There are also many horses that have soundness issues, despite which, can still perform with outstanding ability if they are managed and trained accordingly.
Giving horses the required rest periods (spells) between racing preparations gives them time to heal undiagnosed minor injuries, to their musculoskeletal system, and enables them to return to racing in good health capable of standing up to the forces exerted in their limbs.
It is critical that the welfare of both horses and riders is taken into consideration, which is why flexion and trot ups play such an important part of the training process. These considerations are equally important whenever treatment decisions are made.