Optimizing Microbial Protein Synthesis in the Rumen through Supplementation with Vitamin and Mineral in Ration Based on King Grass to increase Bali Cattle Productivity

Bali cattle have a great potency to supply National meet demand which increase progressively every year. The main constrain in Bali cattle farming is the deficiency in trace minerals on native grass resulting in low Bali cattle productivity. The present study was done to determine the effect of vitamin-mineral supplementation in the ration based on king grass on rumen microbial protein synthesis and its relation to productivity of Bali cattle steer. Randomized Complete Block Design was used in this study consisted of four treatments and five groups based on differences in live weight cattle. Treatment consisting of four treatments and five groups based on differences in live weight of cattle. Treatments consist of: S0 = concentrate as much as 5 kg + king grass given ad libitum, S1, S2, and S3 = S0 successively added 0.1%, 0.2% and 0.3% vitamin- mineral in concentrate. Variables observed were intake and ration digestibility, product of rumen fermentation, deposition of nutrients, microbial protein synthesis in the rumen, live weight gain of the animals, and feed efficiencies. The data obtained were analyzed by variance, and regression analysis used to predict the optimal level of supplementation. Results showed that vitamin-mineral supplementation has significantly (P <0.05) effect to most of the observed variables, except the coefficient of rations digestibility. Supplementation levels of 0.2 to 0.3% can reduce the consumption of nutrients, but supplementation levels of 0.1% can increase concentration of propionate acid up to 37%, 12% retention of energy, efficient use of the ration 16%, microbial protein synthesis 15%, reduce methane emissions of up to 18%, and can increase live weight gain of Bali cattle steer up to 14% (0.58 vs. 0.66 kg/day) than cattle without supplements. The research concluded that vitamin-mineral supplementation 0.1 to 0.3% in ration based on king grass can increase microbial protein synthesis in the rumen and live weigh gain of Bali cattle steer, and there is a clear relationship between microbial protein synthesis (X) with live weight gain of cattle (Y) which follows the equation: Y = 0.002X - 0.002, R2 = 0.73.