a crossbreeding experiment involving four iranian fat-tailed sheep breeds, namely kurdi (k), chaal (c), afshari (a) and sanjabi (s) was carried out to determine the ram breed effects on productivity of kurdi fat-tailed ewes (k) under extensive production system. a total of 475 kurdi ewes were mated to 24 rams from four breeds producing 454 lambs including pure kurdi, kk, (116 lambs), afshari × ...