Horseracing over jumps is a significant sport in the UK. But it also carries a high risk of injury. From 2013-2018 the death rate in National Hunt races, where horses jump fences ditches, was 1 in 250 starts! Most injuries and deaths are related to falls at fences. A study by Pinchbeck et al. (2004) found that factors related to an increased risk of falling included duration of journey to the racecourse, behaviour in the parade ring and weather at the time of the race, age, amount of rainfall and going. However, as fences are designed by people but jumped by horses, and as horses have different vision to ourselves, its conceivable that horses may be deceived by fence colour and configuration.
National Hunt fences have orange visibility markers that are intended to help the horse see Steeplechase fences and hurdles more clearly. These stand out to spectators and jockeys who possess the ability to see a wide range of colours. However, horses only possess dichromatic colour vision, with two cone types, sensitive to short (428 nm peak) and medium wavelengths (539 nm peak) (Carroll et al., 2001) which gives them poorer colour vision than people.
Researchers from Bielefeld University in Germany and the University of Exeter, UK, set out to try and understand how horses might perceive National Hunt Jumps with different coloured markers. Their research was a combination of both theoretical analysis of how jumps may appear to humans and horses and an experimental investigation with racehorses jumping different fences with different coloured take-off boards and guard rails.
One of the major findings was that for horses, orange, the most commonly used colour, had poor visibility and contrast against most surroundings. However, yellow, blue, and white were much more conspicuous.
The authors also investigated how a group of 14 NH racehorses jumped fences with orange, fluorescent yellow, bright blue, or white take-off boards and mid-rails. They found that fence colour influenced both the angle of the jump and the distances jumped with bright blue producing a larger angle of take-off and jumps over fluorescent yellow fences having shorter landing distances compared to orange. White was the only colour that influenced take-off distances, with horses jumping over white fences having a larger take-off distance. Fluorescent yellow was found to have the greatest contrast against the main fence body when used for the mid-rail colour across all different light and weather conditions.
The authors concluded “..that current obstacle coloration does not maximise contrast for horse vision, and that alternative colours may improve visibility and alter behavioural responses, with the ultimate goal of improving safety and welfare.”
Clearly anything that can help to make fences clearer for horses to see will hopefully contribute to less falls, less injuries and less fatalities.
Click HERE for full study.
References
1. J. Carroll, C.J. Murphy, M. Neitz, J.N. Hoeve, J. Neitz. Photopigment basis for dichromatic color vision in the horse. J. Vis., 1 (2001), pp. 80-87.
2. G.L. Pinchbeck, P.D. Clegg, C.J. Proudman, K.L. Morgan, N.P. French. A prospective cohort study to investigate risk factors for horse falls in UK hurdle and steeplechase racing. Equine Vet. J., 36 (2004), pp. 595-601.
A fence at Cheltenham racecourse on an overcast day to human and predicted horse vision. Images illustrate the much higher contrast of white, fluorescent yellow, and blue (in the colour boards) to the fence and its surroundings than the orange take-off board and mid-rail. (Paul & Stevens 2020).
