dutch warmbloods are sound and long-lived due to the stringent requirements placed on stallions and elite mares. while mild navicular changes, sesamoids, pastern arthritis and bone spavin may be permitted on radiographs, osteochondrosis in the hock or stifle is not allowed. horses are disqualified from breeding for congenital eye defects, over- or underbite, or a lack of symmetry in stifles, hocks, hooves, or movement.