In order to find early selection criteria to improve the longevity of show jumping horses in competition, a specific protocol was constructed. Before entering competition, young horses were measured for many traits. These horses were offspring of two groups of sires selected as having the highest and lowest estimated breeding values for functional longevity in jumping competition calculated from progeny. Functional longevity was defined as the time spent in competition corrected for the level of performance. Initial results on subsamples of 346 horses for blood markers and 529 horses for surface temperature from infrared thermography are reported. Key markers of oxidative stress had significant effect on group of sires, especially superoxide dismutase. Surface temperature showed high heritability (up to 0.70) for body and contrast of body with specific locations (fetlocks, hocks, foot, eyes), but only asymmetry in right and left temperature of feet was linked to group of longevity of the sire.