Cold water hydrotherapy for horses

By Associate Professor Evan Hunt MVSc,PhD,G.Dip.Ed(Tert)

Hydrotherapy, or treatment in water, especially sea water has long been used for the treatment of many health conditions in humans and animals. Horses themselves have known the value of standing in cold water to assist in easing early laminitis effects. Human exercise physiologists and physiotherapists have used hot or cold therapy to ease or aid repair of muscle, joint and traumatic injuries. Similar use has been made of sea water by horse trainers around the world when based at coastal locations. All believe the salt water aids in recovery or prevention of some lower leg conditions but few have proof that water, a natural therapy, actually works.

Most trainers and owners have valued the role of, running hose water, application of ice packs, or use of whirlpools or boots as a first line of treatment in many injury situations both as a cleansing agent and also to stimulate healing, however, this has always been regarded as second best to seawater.

As all trainers do not have access to the ocean many interested persons worldwide have attempted to develop water baths suitable for use with horses. Earliest records indicate patent applications being registered in the USA in 1873 and in the UK in 1917 both claiming superior healing and pain management in injured horses. Since those times many other patent applications have been lodged registering improvements in the concept and design but all relied on anecdotal evidence to support claims. Although the concept was simple the practice of spa bathing horses has not been strongly supported. The introduction of effective chemical anti-inflammatory and pain control agents diminished the need. Also hygiene issues associated with faecal or algal contamination of water and problems of water leakage reduced interest overseas. The introduction of regulations for drug free horse sports and mandatory drug testing has, together with the interest in "natural" therapies, reawakened the role of hydrotherapy for horses.

In 1990 Brian Scott of Dubbo, NSW, Australia designed a fibre glass spa bath for horses which overcame some of the previous bath problems. Since then modifications and new designs, updated by Director Terry Connolly of Equine Therapeutic Spas Pty Ltd Australia, to aeration, filtering, temperature control and faecal collection have made the operation of a spa bath for horses an easy and reliable way of providing natural hydrotherapy to the legs of horses.

Hydrotherapy relies on a number of water factors which all may influence the outcome of the therapy:
" The temperature of water has important therapeutic and analgesic influences. The colder the water the more pain relief and anti-inflammatory influence is provided. Also at lower temperatures micro-organic activity is minimized and in trauma or surgical cases cold provides better infection control. The lower the temperature the more dense the water is together with it holding more dissolved oxygen.
" Salt concentration and the make up of the salts in the water will have an effect on the tissue response to water. Sea water contains varying amounts of common salt, sodium chloride, but averaging around 25g/l, and magnesium chloride 1g/l. The higher the salt concentration the greater the drawing action the water has on tissue fluids. Spa bath hydrotherapy allows the introduction of higher salt levels than seawater increasing the healing powers of the water.
" The depth of water increases the physical pressure exerted onto tissues and the deeper the immersion the greater the pressure.

" Aeration of water, creating water turbulence, has a two fold action by giving massage but also dissolved oxygen content of the water is increased. At lower temperatures, below 6 degrees Celsius, dissolved oxygen content increases rapidly above the 2.4ppm contained in still salt water to 4.5ppm and at 2 degrees Celsius aerated water holds 8-11ppm. The higher oxygen level is believed to improve healing just as it does in hyperbaric oxygen chambers for humans and also allows the horses to relax far more than in still cold water or in water at higher temperatures.

In clinical trials undertaken at the University of Sydney-Orange campus by Associate Professor Evan Hunt and reported in the Journal of Equine Veterinary Science in April 2001, together with cases recorded in Texas in USA, and in Gloucestershire in the UK, numerous horses with many types of lower leg injury have responded very well to cold spa hydrotherapy. Twenty g/l sodium chloride and 30g/l magnesium sulphate were included in water that was refrigerated to below 4 degrees.

Most of the research has concentrated on thoroughbred and Standardbred race horses with superficial digital flexor tendon injury (bowed tendons) or suspensory ligament injury. Rapid resolution of some severe tendon lesions (eg SJ and FM) have seen horses back in light training eight weeks after injury and successfully raced within six months. Response to injury depends on the location, severity and how the horse has been treated before access to hydrotherapy. It is important that extended cold therapy be applied to tendon injuries as quickly as possible to minimize the progressive nature of tendon damage.

In several cases of traumatic injury 3-4 days before official competition or racing, where alternate chemical anti-inflammatory therapy would exclude horses from competition, twice daily cold spa hydrotherapy has corrected the inflammation allowing the horses to compete successfully. This aspect has been extremely beneficial to some well known racehorses (MI, QS, Legends, NW) that have been set for major races but minor or chronic injury was likely to stop them from racing. Cases of jarring up have responded rapidly allowing horses to continue on in full training and enter the winners circle.

Three notable returns to racing have been SJ and Legends. Both horses suffered severe damage to the superficial flexor tendon that had been described as limiting their future. In SJ's case spa therapy was continued right through his first preparation allowing him to start and win first up in sprints seven months after a grade three injury. He has since gone on and had another two preparations for another win and numerous close placings. Legends was being prepared for the year 2000 Melbourne Cup when his injury developed as a grade four lesion involving the whole length of the tendon. The nature of the injury meant a longer period of therapy to resolve the lesion and a slower return to racing. He returned to racing 13 months after injury and has placed twice in his current preparation in races from 1400m to over 2000m remaining completely sound.

One recent spa graduate has been Ice Box who won in class record time on a dead track at his first start back after bone chip removal from a knee fracture only eight months after his operation. Normally after arthroscopic surgery horses spell for at least nine months before starting work. A week after Ice Box was operated on he started three times a week cold spa treatment and commenced forced walking at four weeks. He continued with a slow increase in work while continuing spa treatment for the next four months before returning to the trainer when faster work commenced.
At that time other support anti inflammatory treatment and joint support therapy was included as would be normal for horses of this type. The approach to use of cold therapy has followed the human lead where cold therapy for knee surgery has been found to reduce pain, level of infection and rapidly reduce time to effective weight bearing.

More recently hydrotherapy value has been recognized with severe cases of skin injury where granulation (proud flesh) has developed. In association with conventional bandaging hydrotherapy every second day has resulted in rapid wound closure without the normal enlargement and distortion of shape that is found in many slow healing wounds.

In the UK a number of older dressage, pleasure and hunt horses suffering varying degrees of lameness associated with joint arthritis have successfully been treated with removal of lameness, improved general gait and demeanor even though joint bone changes on X-ray have not altered but joint effusion is reduced. Similar results in the response of tendon injury are being seen as in Australia.

In the USA cold spa hydrotherapy has primarily been used on young Cutting horses being prepared for the futurity competitions. These young horses work very hard as 2 and 3 year olds and many develop fetlock and hock problems that have been found to respond very favourably to hydrotherapy. Some young horses with high potential had been dropped out of the training due to chronic lameness, even after repeated joint injections, but since the introduction of cold spa hydrotherapy have returned to training and have then won high valued competition.

A common outcome of all the clinical cold spa hydrotherapy treatments has been an overall improvement in movement generation by the horse. It is quite apparent that in many cases an injury to one leg had been masking an overall unrecognized problem, which was corrected at the same time as the principal injury treatment.

In the future it is envisaged that cold spa hydrotherapy could well be used as a preventative modality in racing and competition horses where the rigors of competition and training create continuous concussive forces on lower joints. After all this was one of the concepts of those who used to stand coach and transport horses in cold running streams after a days work. It is also this concept that so many racehorse trainers world wide try to emulate when placing lower legs in ice packs after training. Recent research in USA from Ohio University has demonstrated that cold running water is the most effective way of reducing tissue temperature in the legs of horses but cold spa hydrotherapy although not included in that research cools the legs to a far greater degree and the legs stay cold for longer because of the controlled lower temperature of the water.

Much research still needs to be completed to understand the way in which cold spa hydrotherapy aids in healing but the rapid increase in knowledge being accumulated across the world is now demonstrating that many conditions of the lower leg benefit from preventative as well as therapeutic actions. The concept most recently advanced by Australian design and manufacture has been accepted more readily overseas where alternate therapies are more widely practiced. The recent examples in the Australian media showing horses standing in buckets of iced water could well be replaced by the advantages demonstrated from within our own industry.