The Effect of Aromatherapy on Equine Facial Expression, Heart Rate, Respiratory Tidal Volume and Spontaneous Muscle Contractures in M. Temporalis and M. Cleidomastoideus

The ability to calm horses affects both the safety\r\nand well-being of human-horse relationships. However, not many natural\r\ncalmatives are known, nor the efficacy of these in supporting a state of\r\ncalmness in horses. This study used both qualitative and quantitative methods\r\nto test whether aromatherapy has a measurable and calming effect on equine\r\nfacial expression and a range of physiological parameters. Nine horses of\r\ndifferent ages, genders and breeds were included in a crossover design with\r\nhumidified essential oils to determine the calming effect of vetiver (Vetiveria\r\nzizanioides), spikenard (Nardostachys jatamansi) and roman chamomile\r\n(Anthemis nobilis) in relation to water (negative control) and lavender\r\noil (positive control) in horses standing still. The results revealed\r\nsignificantly lowered heart rate (P \u003c 0.05 - \u003c0.001) and respiratory\r\ntidal volume (P \u003c 0.05 - \u003c0.001) for the tested essential oils, while\r\nspikenard oil was best at inducing a relaxed facial expression (60% of the\r\nfull-time scale for 8 horses; 75% of the full-time scale for 7 horses) and\r\nroman chamomile oil was statistically most successful at reducing the incidence\r\nof spontaneous muscle contractures in M. Temporalis (P \u003c 0.001) and M.\r\nCleidomastoideus (P \u003c 0.05) compared to the other aromatherapy treatments.\r\nIt is concluded that aromatherapy has both qualitative and quantitative effects\r\non physiological parameters in static horses, and moreover, that essential oils\r\nappear to have a calming effect.