Characteristics and sleep deprivation in the horse

Sleep is a vital biological process that is decisive for the physical and psychological welfare of the horse. Despite its importance, equine sleep patterns and disorders remain less well understood than those of humans or other domestic animals. This review summarises current evidence on equine sleep architecture, its polyphasic nature, associated postures and behaviours, and the environmental, social, clinical and management factors that influence it, together with the signs, types, consequences, differential diagnosis and management of sleep deprivation, with particular emphasis on recumbent sleep deprivation. Current tools for objective assessment, polysomnography, wearable sensors and accelerometers, and sleep quality indices, and their implications for welfare and performance are also discussed. Recognising and preventing sleep deprivation is a priority objective for owners, veterinarians, and equestrian professionals.