Research on post-weaning weight gain in domestic camelias reared under two diferent nutritional regimes was conducted at the IVITA camelid research station in Marangani,(Cusco,Pera),withtheobjectiveofdeterminingtheeffectofnutritiononlive weightoffemalealpacasandllamasatoneyearofage.Inthefirstregime,T,,twogroups of30alpacasand30llamaswereeachkeptin2hectaresofcultivatedpastureona7day graze/40dayfallowrotationpattera. Inthesecond,T2,twogroupsof30alpacasand30 llamas were each grazed on the same 15 hectares of native pasture throughout the experiment.Attheendoftheyear,only27%(8/30)ofthealpacasand47%(14/30)ofthe llamasgrazedonnativepasturehadreachedweightsof30kgand50kgrespectively,the mínimumrequiredforbreeding,while87%(26/30)ofthealpacasand93%(28/30)ofthe llamas reared on cultivated pasture achieved the required minimum. These figures demónstrate thatthe use ofcultivatedpasturein the dietofpost-weaning alpacas and llamassignificantlyincreasesthenumberoffemaleswhichcanreproduceatoneyearof ageand,thus,canplayanimportantroleinimprovingherdproductivity.