The effect of tallow and blended tallow plus poultry fat (4:1) on feedlot performance , carcass composition and digestibility were studied. 90 kordian yearling bull (initial body weight = 224±18 kg) were divided, based on weight and , assigned to one of three diets containing 0(CR) ,5% tallow (TR) and 5% blended fat (BR) . Bulls were adapted to the diets over aperiod of 15-d, followed a 98-d feeding period. Bulls were slaughtered and carcass characteristics were evaluated . Apparent digestibility . of fat in CR was lower (p<0.05) than in TR and BR (59.3 versus 68.84 and 78.5% ) . The digestibility of neutral detergent (40.5%) and acid detergen fiber (38.5%) of BR were lower than TR (47.0 and 42.0) and of CR (49.2 and 44.1% , respectively) . Average daily gains were 0.735,0.864 and 0.930 kg for CR , T R (p<0.05) and BR , respectively . feed conversion ratio of BR and TR were (p<0.05) superior to CR ( 7.92 and 8.34 versus 10.77) . supplemental fat did not affect dressing percentage (54.18,55.00 and 54.33 for CR,TR and BR , respectively) , fat thickness, longissiums muscle area (sq cm ) , chanel fat % (pelvic+ heart fat) and chemical composition of boneless meat of 10-11-12 ribs . In conclusion, inclusion of fat in diets improved performance and feed efficiency and resulted in substantial economic benefits, particularly , for belended fat.
)