Optimising Rumen Function of Bali Cattle Fed Ration Based on Agriculture By-Products with Supplementation of Multivitamins-Minerals

A research has been carried out to optimize the rumen function and the rumen microbial protein synthesis in Bali Cattle (Steer). Sixteen Bali cattle were used in this experiment with Completely Randomized Block Designed four treatments and four blocks. The first treatment was ration based on agriculture by products without supplementation (R0), while the other three treatments were supplemented with 0.075% (R1), 0.150% (R2) and 0.225% (R3) multivitamins-minerals. The variables of rumen microbial protein synthesis including urinary exretion of allantoin, purin derivatives absorbsion, rumen microbial protein synthesis and efficiency of rumen microbial protein synthesis, Feed and nutrients degradation on the rumen, pH, concentration of NH3-N, VFA and amount of protozoa in the rumen fluid were measured in the experiment. The result showed that rumen microbial protein synthesis and amount of microbial purines absorbed in suplementation of 0.150% (R2) and 0.225% (R3) multivitamins-minerals were significant difference (P<0,05) compared with without supplementation (R0) (222.83 and 222.24 gram/day Vs 197.83 gram/day) and (49.45 and 49.35 Vs 44.76 mmol/day), but they were not significantly different with without supplementation on rumen microbial protein synthesis (213.57 gram/day) and on amount of microbial purines absorbed (48.67 mmol/day). Degradable organic matter and Sulfur absorbed in the rumen, amount protozoa, and ruminal pH, concentration of NH3-N, totally VFA and propionate acids of rumen fluid significantly (P<0,05) increased as well. Increasing supplementation until 0.15% (R2) multivitamins-minerals were decreased concentration of acetate acid, butirate acid and methane gas production compare with without supplementation, but increasing until 0.225% supplementation of multivitamins-minerals (R3) increased concentration of butirate acid and methane gas production. Moreover, regression analyzed showed that suplementation of multi vitamins-minerals of 0.188% coused maximum rumen microbial protein synthesis of 223,39 gram/day. It was concluded that rumen microbial protein synthesis of Bali cattle given ration based on ammoniated rice straw could be increased as maximum 12.92.%. The level optimal multivitamins-minerals supplementation used in this experiment was 0,188%.