Effects of Tannin-containing Supplement on Enteric Methane Emissions, Total Digestible Nutrient, and Average Daily Gain of Local Indonesian Beef Cattle

Reducing methane (CH4) emissions is one of the most critical goals in ruminant nutrition. This study aimed to evaluate the effect of concentrate and tannin supplementation on the mitigation of methane gas in Indonesian local beef cattle. The current study was conducted in vivo using 12 Bali cattle using a completely randomized design with four treatments and three replicates. Cattle were fed a basal ration with field grass (control), the addition of concentrate 25% dry matter (DM) ration no tannin as well as tannin supplemented in concentrate at levels of 0.12% and 0.18% of DM concentrate. The concentrate contains 7.5% crude protein and 71.25% total digestible nutrients and tannin supplementation using gambir (Uncaria gambir Indonesia) tannin extract. The parameters measured were apparent digestibility, total digestible nutrients, methane production, and average daily gain. The results showed that concentrate addition significantly increased DM consumption, crude protein digestibility, and total digestible nutrients. Supplementation of 0.18% tannin in concentrate can mitigate 49.7% methane gas production resulting in energy efficiency, which was reflected in the weight gain rate of 0.75 kg/day. In conclusion, present results suggest that the supplementation of 0.18% gambier tannin extract in concentrate could be considered a suitable feed additive to mitigate methane gas production and increase the average daily gain of Indonesian local beef cattle.