▁dur able ▁and ▁less ▁sus cept ible ▁to ▁disease . ▁In ▁addition , ▁the ▁animal ▁could ▁be ▁b red ▁on ▁marg inal ▁gra zing ▁land ▁with ▁no ▁farm ▁infrastr ucture ▁and ▁with ▁minimal ▁husband ry ▁in ▁huge ▁state ▁agricult ural ▁far ms ▁( S AF s ). ▁From ▁ 1 9 5 8 , ▁the ▁work ▁on ▁ż ub ro ń ▁her ds ▁was ▁continued ▁by ▁the ▁Polish ▁Academy ▁of ▁Sciences ▁in ▁various ▁labor ator ies , ▁most ▁not ably ▁in ▁B iał owie ż a ▁and ▁M łod zik owo . ▁During ▁the ▁first ▁ 1 6 ▁years ▁of ▁experiments , ▁a ▁total ▁of ▁ 7 1 ▁animals ▁were ▁born , ▁including ▁Fil on , ▁the ▁first ▁ż ub ro ń ▁born ▁to ▁a ▁ż ub ro ń ▁mother ▁( August ▁ 6 , ▁ 1 9 6 0 ). ▁The ▁animal ▁was ▁intended ▁to ▁become ▁a ▁hard y ▁and ▁cheap ▁alternative ▁to ▁cattle . ▁ ▁The ▁experiment ▁was ▁continued ▁until ▁the ▁late ▁ 1 9 8 0 s , ▁when ▁the ▁results ▁of ▁the ▁bre eding ▁program mes ▁were ▁de emed ▁uns atisf actory . ▁Vari ous ▁factors ▁contributed ▁to ▁this ▁decision , ▁including ▁the ▁severe ▁economic ▁difficulties ▁of ▁the ▁Polish ▁social ist ▁economy ▁in ▁the ▁ 1 9 8 0 s , ▁a ▁lack ▁of ▁interest ▁from ▁the ▁not or iously ▁in effect ive ▁S AF s , ▁and ▁fear s ▁that ▁ż ub ro ń ▁would ▁cross bre ed ▁with ▁the ▁end anger ed ▁wild ▁wis ent , ▁cont