Prevalence and impact of lighting regimes on the circadian rhythms and behaviour of stabled horses in the UK

Light plays a significant role as a regulator for circadian rhythms, and arousal and sleep behaviours in most mammalian species. Modern horse husbandry practices can involve significant time spent indoors, involving variable exposure to light under different lighting regimes. Little evidence exists that can be used as a guide for horse care givers on best practice in the use of light in equine husbandry, whilst little is known about how lighting is managed and the extent of the variability. This study aims to report novel information about the prevalence of different lighting regimes employed in stables/barns in the UK. An online questionnaire using MS Forms has been launched to gather responses from a broad variety of UK-wide equine establishments. Using a blend of categorical, Likert scaled and open-field questions, responses to the questionnaire will provide an overview of the different light schedules that stabled horses experience, details about late night checks, and perspectives on the importance of light relative to equine sleep. Following the application of standard ana lytical techniques such as the Chi-Squared test of association (categorical questions) and Kruskal Wallis one way ANOVA (Likert scaled questions) the results will be discussed in the context of existing knowledge about the influence of lights on stabled horses. For example, in a recent study investigating the influence of a stan dardised red/white LED lighting system, compared to fluorescent tube lighting, on the behaviour and circadian synchronicity of stabled horses, we discovered no significant differences in clock gene expression, sleep be haviour, or blink rate between the two lighting conditions. This is in contrast to results of research showing how circadian disruption can occur when late night checks involving white light are used. The outcomes from the discussion aim to help inform future research and industry practice, whilst the results of the questionnaire will serve to demonstrate how widely these recommendations need to be promoted to help both the equestrian sector and horse care givers to facilitate optimal equine wellbeing.