Although most experienced horse owners can identify heat in a leg or foot – usually indicating inflammation, a pulled tendon or an abscess – there are often symptoms of discomfort or poor performance where the horse is showing no physical signs of injury.

The human touch cannot identify changes in temperature of less than 2˚. This, according to Jeanri Mellanby, a Level 2 thermographer who works for Comtest in Midrand, is where thermography comes in.

A thermal camera can "see" and detect changes of less than 0,5˚, making it easy to -identify problem areas, where heat is not -obvious to the touch. The thermal -camera takes a "picture", which is displayed as an -instant, clear image on an LCD screen, -enabling a -diagnosis to be made by a medical -professional and treatment to be carried out.

Used extensively in the equine world since the 1996 Olympic Games, infrared thermal imaging inspections are a quick non-contact method of examining a horse to identify and locate the source of problems or injuries, she explains. Thermography as a science has many applications, but for horses there are three main benefits:
• Prevention of injury in especially competition horses during training by monitoring that no undue stress is placed on the horse which may result in a potential injury.
• Diagnosis by identifying damaged -tendons, ligaments, navicular, laminitis and the source of non-specific lameness as well as musculoskeletal injuries, tooth and jaw problems and locating the source of miscellaneous strains, sprains and injuries.
• Treatment monitoring by assessing the -level of improvement or deterioration -during treatment. Also important here is the monitoring of hoof balance and maintenance.

As thermography is completely non-invasive, it allows the horse to be examined without being touched, thus causing no stress or discomfort. The latest generation of thermal cameras are small and hand-held, enabling the examination of the horse to take place in its own environment, eliminating the need for costly transportation to a veterinary clinic.

How does it work?
Using an infrared thermal imaging camera, the horse can be scanned and a realtime -image is shown on the LCD. Sensors within the -camera convert infrared radiation (heat) -emitted from the surface of the skin, into electrical -impulses that are shown on the image as areas of colour.

White represents the hottest temperature and is found on areas where there is major blood flow including parts of the face and the coronary bands, down through red, -yellow, green to blue and finally black which represents the coldest areas.

A blue streak, -indicating a lack of temperature, can indicate pinching or pressure for example on a nerve root in the neck, while a pink or white area can indicate soft tissue, muscular or tendon damage.

As there is a high degree of thermal symmetry in the body, abnormal or asymmetrical changes that are usually indicative of a problem can be easily identified. An experienced operator can interpret these images and advise the owner or trainer where there is an area of abnormal temperature, allowing a veterinary surgeon to diagnose and treat the problem.

Owing to advances in technology, the latest generation of cameras is hand-held, portable and battery operated. The sensors, which were originally developed for military use, can detect changes in temperature of 0,08°, which can prove invaluable in locating the exact source of the problem.

Thermal cameras have the facility to save the thermal images to an internal memory card for download to a PC. This ensures that a permanent record of the problem is available for the veterinary surgeon to refer to and allows subsequent scans to show the effectiveness of treatment.

Thermo-benefits
One of the benefits of thermal imaging, -according to Jeanri, is the speed with which an entire examination of the horse can be carried out. It is very often the case that a symptom that shows up as pain in the back, for example, actually has its root cause somewhere else, for instance the foot.

The horse will very often compensate for the injury by transferring its weight to the other leg, causing twisting and undue stress along the spine. Traditional methods of diagnosis would be to treat the back, give physiotherapy treatment or rest the horse.

According to Johannesburg-based farrier, Chris Connick, farriers are also starting to use thermography to look at the changes that occur in a horse’s foot, and are developing methods of balancing and shoeing based on these results. Research based on thermography findings, will also allow further understanding of problems in the feet caused by laminitis, which has profound effects on the blood flow to the foot.

Another application of thermography, Jeanri points out, is with the pre-purchase vetting of horses, where underlying problems can be picked up.

While nothing can replace the experience of vets and traditional horsemen gained over many years of working with horses, thermo-graphy is now being recognised as an effective method to assist veterinary diagnosis.