▁America , ▁ad her ed ▁to ▁many ▁aspects ▁of ▁the ▁German ▁bre eding ▁program , ▁where by ▁member ▁k enn els ▁may ▁only ▁choose ▁to ▁bre ed ▁dogs ▁that ▁were ▁cert ified ▁as ▁three ▁generation ▁free ▁of ▁hip ▁d ys pl asia . ▁As ▁a ▁likely ▁result , ▁the ▁inc idence ▁of ▁hip ▁d ys pl asia ▁in ▁the ▁bre ed ▁was ▁reduced ▁to ▁almost ▁ 1 0 % ▁and ▁the ▁occurrence ▁of ▁O FA - r ated ▁" Ex cell ent " ▁h ips ▁increased ▁by ▁over ▁ 6 0 % ▁in ▁just ▁ 2 0 ▁years . ▁Current ▁inc idence ▁rates ▁of ▁hip ▁d ys pl asia ▁in ▁Leon berg ers ▁are ▁likely ▁around ▁ 1 3 %. ▁After ▁ 2 0 1 0 , ▁when ▁the ▁Leon berger ▁Club ▁of ▁America ▁joined ▁the ▁American ▁Kenn el ▁Club , ▁the ▁formerly ▁strict ▁bre eding ▁rules ▁are ▁no ▁longer ▁mand atory ▁for ▁all ▁Leon berg ers . ▁ ▁Though ▁not ▁common , ▁Leon berg ers ▁do ▁inherit ▁and / or ▁develop ▁a ▁number ▁of ▁dise ases ▁that ▁range ▁in ▁their ▁impact ▁from ▁m ild ▁to ▁dev ast ating . ▁In ▁addition ▁to ▁hip ▁d ys pl asia , ▁Leon berg ers ▁can ▁inherit ▁and / or ▁develop ▁heart ▁problems , ▁inherited ▁Leon berger ▁par al ysis / poly ne urop ath y , ▁o ste os ar com a , ▁hem ang ios ar com a , ▁o ste och ond ros is ▁dis sec ans , ▁all erg ies , ▁dig