By: Dr. Joan Norton

HSI’s resident vet, Dr. Joan Norton, reviews new products and the latest research in the world of veterinary medicine.

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Arnd Bronkhorst photo

Horsemen have always recognized the relationship between our own emotions and the reactions of our animals. They can “smell fear” and sense when we are sad, but do they share in our stress over upcoming competitions? In 2009, researchers at the Swedish University of Agricultural Sciences at Uppsala1 recognized that prior research in equestrian sciences focused on how intentional signals, given by an experienced rider during training sessions can affect a horse’s performance. However, unintentional signals may be more important to the human-animal bond. To show that human emotional responses can be translated to our horses, this group performed what is affectionately known as the ‘Umbrella Study’. In brief, a horse and handler were made to walk the length of an area several times; the human was told that on the last pass an umbrella would be opened and closed in front of the horse. The heart rate of both the horse and handler were monitored.

Not surprisingly the anticipation of the opening umbrella increased the heart rate of all handlers, regardless of their experience. The interesting result was that even though the umbrella was never deployed, the heart rates of the horses increased with their handlers. The authors concluded: “thus the heart rate of the horse increased when the person ‘thought’ the horse might be frightened by the umbrella.”

Even without direct cues, these horsemen were able to unintentionally transfer their emotions to their horses.

Stress Response

While the ‘Umbrella Study’ looked at the simple parameter of heart rate and a potentially traumatic event of an unexpected umbrella, a recent study by the Graf Lehndorff Institute for Equine Sciences, in Neustadt, Germany has delved deeper into the stress response of both horse and rider with regards to competition.

It has previously been shown that horses involved in competitive events have an increased stress response but this has only recently been correlated with rider stress levels.

Horse and rider pairs were asked to perform a task that included cantering in a ring and jumping a course of 18 fences. First the pair was allowed to practice the routine in the ring with no spectators present. After this schooling session, they repeated the course, but this time the stands were full of spectators and judges, simulating a proper competition. Stress parameters such as heart rate, heart rate variability and saliva cortisol concentrations were measured before and after each round. Both heart rate and cortisol levels were found to be elevated in horses and humans immediately after both the practice and “show” rounds, when compared to the pre-round baseline. It seemed that there was no added cortisol elevation in response to the crowd of onlookers, however increase in heart rate was much more pronounced in the riders when there were spectators.

There was also a more pronounced decrease in heart rate variability (a sign of stress) in the humans during the “show” than their horses. So while both horse and rider experienced some level of stress during training and showing, the riders had a much more profound reaction to the crowd than their horses.

So the next time you trot into the ring at a show, take a cue from your horse, forget about the crowd and enjoy the ride!

Early detection of inflammation or infection in the horse is key for effective treatment and rapid recovery. Previously veterinarians have relied on white blood cell counts or fibrinogen, an acute inflammatory protein, as markers of inflammation in the body.

The drawbacks of these indicators are that changes can take 24-48 hours to detect in the bloodstream and commercial testing delays reporting of the results by hours and sometimes days.

However, recently, a new inflammatory protein3 has been recognized as an accurate and earlier indication of a problem in the horse. Serum amyloid A protein (SAA), produced in the liver in response to inflammation, increases more rapidly and more markedly than fibrinogen or WBCs, making it a more sensitive and earlier indicator of inflammation. Because it also decreases more rapidly in response to resolution of disease it can be used to monitor response to treatment protocols.

To further speed the detection and diagnosis of infection or inflammation, a UK-based firm, StableLab®, has developed a handheld stall side test that gives immediate results. The test requires less than a milliliter of blood be mixed with a reagent and placed on a test cartridge. An easy to read color band appears in the test window in only 10 minutes time. The color can then be compared to a reference card to determine the quantity of SAA in your sample. Test cartridges can even be labeled and stored for day-to-day comparisons.

StableLab® provides veterinarians and owners with a way of rapidly detecting inflammation and more accurately monitoring recovery.

Therapeutic Ultrasound

Therapeutic ultrasound can be applied in two different sequences; pulse wave ultrasound affects the cellular environment promoting blood flow and healing, while continuous wave ultrasound produces a thermal effect. The benefits of heat inducing ultrasound include decreased muscle spasms, pain relief, increased collagen elasticity and blood flow.

In order to obtain the benefits of thermal ultrasound, the tissue temperature must increase by 2-4°C. While this easily achievable in humans and our small animals, its feasibility has never been evaluated in the superficial tendons or deeper musculature of horses – up to now.

A group of researchers at the University of Tennessee applied therapeutic ultrasound to the distal limb and epaxial (back) muscles of the horse and measured the tissue temperature to see if an effective increase could be reached.

When the lower limb was heated with continuous ultrasound for 10 minutes per ERA (5.0 cm2) using a frequency of 3.3 MHz and an intensity of 1.0 W/cm2, both the superficial digital flexor tendon (SDFT) and the deep digital flexor tendon (DDFT) saw a mean temperature increase of 2.5°C and 3.5°C respectively.

However, continuous ultrasound for 20 minutes per ERA (5.0_cm2) using a frequency of 3.3 MHz and an intensity of 1.5 W/cm2 could not produce a >2°C increase in the much larger back muscles, even at the most superficial point measured.

This indicates, that while heat producing therapeutic ultrasound may be beneficial for pain management and healing in the distal limbs, it does not generate enough heat to benefit horses when used on larger muscle groups like the epaxial muscles.

Shock Wave Therapy for Wound Healing

Extracorporeal Shock Wave Therapy (ESWT) has long been used to treat tendon and ligament injuries in horses. Studies have shown that shock wave therapy shortens healing time and improves the quality of tendon repair. In addition to increasing neovascularization (the generation of new blood vessels), ESWT increases the activity of cells and production of tissue healing growth factors. It is because of these benefits that ESWT has been applied to wound healing in human medicine.

Wound healing is particularly challenging in the distal limb of the horse where circulation is poor and there is a propensity for excessive granulation tissue (proud flesh) to develop. In a recent study5 at The University of Guelph, in Ontario, Canada, researchers found a significant reduction in one of the molecules responsible for granulation tissue production. The combination of increased blood vessel production and reduced granulation tissue may lead to quicker wound healing with fewer complications. Further studies must be done to determine the exact shock wave protocols to illicit the greatest wound healing, but keep an eye on this treatment modality for wound healing.

Tape Training

In the 2012 London Olympics neon kinesiology tape colored the bodies of athletes on the tennis court, the track and most noticeably the beach volleyball sand. Designed to improve circulation, the flow of lymphatics, and at times, stabilize a joint, kinesio-tape has become a key training tool for professional athletes and weekend warriors alike.

Now that technology is being applied to our sport horses. Equi-Tape®, developed by RS Bioceuticals and Dr. Beverly Gordon, is designed with the equine athlete in mind. Special adhesive helps the non-latex tape stick without having to the clip the hair and step- by-step tutorials on the website show all horse owners how to apply the bands.

The product claims to improve circulation to aid your horse’s movement, performance and even recovery. With its use, you can decrease pain and inflammation while improving circulation and range of motion. It is particularly effective at reducing swelling and bruising.

Dr. Gordon feels that one of the greatest benefits can be seen when the tape is applied for training, allowing horses to build stronger muscles and enhance any conditioning program. Taping protocols have been designed for the back, neck, gluteal muscles, sacroiliac joint area and the suspensory ligament and flexor tendons of the lower limb.

While there are no large clinical or controlled research trials evaluating the tape’s efficacy on the horse, single horse trials using thermography show a significant increase in blood flow at, and around, the area of taping.

To fully understand the principles and master the techniques, look for an Equi-Taping™ Method and Strategies course (CETP).