▁( 8 %). ▁In ▁a ▁ 2 0 0 3 ▁USA / Can ada ▁Health ▁Survey ▁with ▁a ▁smaller ▁sample ▁size , ▁the ▁leading ▁causes ▁of ▁death ▁were ▁cancer , ▁he p atic ▁disease , ▁and ▁imm une - medi ated . ▁ ▁American ▁C ock ers ▁previously ▁high ▁popular ity ▁resulted ▁in ▁the ▁bre ed ▁frequently ▁being ▁b red ▁by ▁back yard ▁bre ed ers ▁or ▁in ▁pu ppy ▁mill s . ▁This ▁ind isc rim inate ▁bre eding ▁has ▁increased ▁the ▁pro l ifer ation ▁of ▁bre ed ▁related ▁health ▁issues ▁in ▁certain ▁blood lines . ▁ ▁American ▁C ocker ▁Span iels ▁are ▁sus cept ible ▁to ▁a ▁variety ▁of ▁ill ness es , ▁particularly ▁in fe ctions ▁affect ing ▁their ▁ears ▁and , ▁in ▁some ▁cases , ▁their ▁eyes . ▁Although ▁the ▁number ▁or ▁percent ▁of ▁aff lic ted ▁dogs ▁is ▁not ▁known , ▁progress ive ▁ret inal ▁at ro phy ▁( P RA ), ▁gla u com a , ▁and ▁cat ar act s ▁have ▁been ▁identified ▁in ▁some ▁members ▁of ▁the ▁bre ed . ▁The ▁American ▁Span iel ▁Club ▁recomm ends ▁annual ▁eye ▁ex ams ▁by ▁a ▁veter inary ▁o ph th alm ologist ▁for ▁all ▁dogs ▁that ▁are ▁to ▁be ▁used ▁for ▁bre eding . ▁Auto imm une ▁problems ▁in ▁C ock ers ▁have ▁also ▁been ▁identified ▁in ▁an ▁unknown ▁number ▁or ▁percent ▁of ▁the ▁bre ed , ▁including ▁auto imm une ▁hem ol yt ic ▁an emia ▁( AI HA ). ▁Ear ▁infl amm ations ▁are