Efficacy of androstenone in reducing stress- or fear-related responses of horses during riding

Androstenone, which derived from boar pheromones, known as an interomone, has been documented to change behavior in dogs and horses. It could be a potential candidate for use in pheromonal therapy in horses. This study aimed to investigate the effect of androstenone treatment for improving the safety of horseback riding by reducing undesirable behavior of horses. In this study, fourteen horses were participated in a series of behavior tests with one rider to determine the effects of androstenone on behaviors. First, in the riding test without obstacles, the riding session lasted for 30 minutes with 5 minutes of walking, 10 minutes of trotting, 10 minutes of cantering, and 5 minutes of walking. The frequency of undesirable behavior during the riding sessions was monitored. Second, in the riding test with obstacles, the time to pass through from start line to finish line through an obstacle course was recorded. The course was organized with three consecutive blue tarps. Both tests used a cross-over design with 20 μg of androstenone. In the riding test without obstacles, horses exhibited a significantly reduced frequency of undesirable behavior when treated with androstenone (P < 0.05). During obstacle course test, the horses completed the course faster under the influence of androstenone (P < 0.05). The placebo treatment did not result in a significant behavioral change in either test. These preliminary findings, limited by the small number of horses and the rider, warrant further invesgitation to substantiate the efficacy of androstenone for pheromonal therapy in equine practices.