Dorsal Displacement Soft Palate
Unlike many other species, horses are obligate nasal breathers, meaning they cannot breath through their mouths due to a tight seal that the epiglottis makes with the soft palate. While the epigottis normally lays on top of the soft palate, DDSP occurs when the palate slips above the epiglttotis. The expired air exiting the trachea flows under the soft palate, reducing airflow and therefore performance.