Equine vision research to influence jump racing obstacle design

The colours deployed on hurdles and fences on British racecourses may be set to change following research led by the University of Exeter into the way that horses perceive colour.

The research, commissioned by the British Horseracing Authority (BHA) and Racing Foundation, was undertaken by Dr. Sarah Paul and Professor Martin Stevens of the University of Exeter with the aim of improving obstacle visibility for horses, thus reducing the risk of falls and injuries for horses and jockeys. 

Horses can see some colours; but not the same range of colours that humans do. 

Humans and other primates have three types of light-responsive cells (cones) in their eyes, giving what is called trichromatic colour vision. Normal human eyes detect four basic colours: red, green, yellow and blue. They can also differentiate up to 100 subtle variations in hue. Humans with red-green colour vision defects can only see two basic colours - yellow and blue.

Horses, in common with other non-primate mammals, have only two types of cone giving dichromatic vision. The colours seen by the horse are likely to be similar to those seen by humans with red-green colour blindness.

Presently, the colour used on hurdle frames and fence take-off boards and guard-rails is orange, based on human vision. However, as horses see colours differently, it is likely that the orange does not make the obstacle more visible to the horse.

The research phase of the project included testing the visibility of orange markers and other potential colours at 11 racecourses, and – in collaboration with trainer Richard Phillips – testing the behavioural responses of horses to more prominent colours in a controlled environment.

Orange was confirmed as having decreased visibility and contrast for horses against a range of natural and obstacle backgrounds.

The researchers found that yellow, blue, and white are more conspicuous against fences and their surroundings (foreground/background) than orange, especially yellow fluorescent colours.

The results were consistent under different weather conditions and time of day, except that yellow becomes less visible against the foreground turf under shade, whereas blue, white, and orange are more visible under shade. This effect of shade does not occur for other parts of the fence/hurdle, whereby fluorescent yellow remains most conspicuous.

The jumping responses of horses to fences with orange, yellow, blue, or white take-off boards and guard rails was tested.

The researchers found that the colour of the fences plays a role in both the angle that horses jump a fence and the total distance. Horses adjust their jump angles with colours that are different to orange, and white tends to produce a longer total jump distance.

The optimum colour combination, which is likely to combine the best features of visibility and horse responses under a range of conditions, is to use fluorescent yellow for all hurdles and guard-rails, and fluorescent white for take-off boards. This maximises visibility under all conditions while potentially facilitating better behavioural responses.

As a result, a recommendation has been approved by the sport's Racecourse Committee for a trial using fluorescent yellow for all hurdles and guard-rails, and fluorescent white for take-off boards at fences.

The images on the left show what a human sees compared to what a horse sees (shown on the right). Credit: University of Exeter

These colours have been determined to maximise visibility under a wide range of conditions for both humans and horses.

Retired jockey Ian Popham and conditional jockey Danny Hiskett acted as riders of the horses throughout the trial.

Ian Popham said: "From riding over the different coloured fences it was clear to me that over some colours the horses reacted differently and showed the obstacle more respect.

"I'm sure other riders will feel the same and this feels like a great idea and opportunity to make the sport safer for both horses and jockeys."

It has now been agreed that the next phase of the project should see a more extensive trial take place at training grounds to build up a significant dataset before rolling the trial out to a live racing environment.

The results of this research and the ongoing trials will be shared with other racing jurisdictions and equine organisations.

David Sykes, Director of Equine Health and Welfare for the BHA, said: "This fine and important project is an example of how British racing uses advanced scientific and veterinary research to constantly improve racehorse welfare, not only for thoroughbreds in Britain but across other nations and equine disciplines.

"As with the ongoing phased introduction of our padded hurdles – which have proven to reduce faller and injury rates – we will ensure to take our time with this project, make sure there are no unintended consequences and that the evidence of the ongoing trials continue to support the case for change.

"If that proves to be the case then we will look forward to seeing the new designs of hurdles and fences on racecourses, and hopefully further reducing our already declining faller rate."