The effects of inorganic and organic Zn, Cu and Mo  supplementation to the in vitro digestibility of Elephant grass were  studied in this trial. The in vitro trial used the TILLEY dan TERRY  method modified by VAN SOEST with the incubation of the grass for 48  hours in sheep rumen liquor medium. Mineral added as fonn of organic and  inorganic. The treatment of mineral inorganic supplementations were by  adding single e1emen Cu, Zn and Mo and its combination. Mineral added  was Zn (as chloride and sulphate salts) 5 ppm, Cu (sulphate salt) 0,1  ppm dan Mo (molybdate salt) 5 ppm, with 4 replicates. Meanwhile the  organic minerals added were in the proteinate fonns. Parameter measured  were in vitro dry matter digestibility (IVDMD), in vitro organic  matter digestibility (IVOMD), pH, VF A total and NH3. Statistical  analysis was done by using Complete Split splitsplot design. The  supplementation increased pH value, VFA total, IVDMD and IVOMD value  (P<0,05) and decreased NH3 value. The highest IVDMD and IVOMD values  obtained at the mixture supplementation of mineral Zn (as Zn S04), Cu  and Mo, from 58,31 became 69.73% and 52.22 became 62.55% respectively  for IVDMD and NOMD. pH value increased from 6.48 to 7.05 and ammonia  content decreased from 1,17 to 0,14%. The organic mineral  supplementation, en-proteinate dan Zn-proteinate showed that the adding  of Zn, Zn and Mo, Zn and Cu also the combination of Zn, Cu and Mo,  resulted in IVDMD values as 70.29; 69.97, 64.12 and 63.93%. Further more  IVDMD value at the supplementation of Cu and the combination of Cu and  Mo were 65.08 and 60,49%. It can be concluded that the supplementation  of minerals in the form of inorganic or organic  couldimprove the IVDMD  values Key words: Three element, in vitro digestibility, sheep
                        
                        
                        
                        
                            
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