Effectiveness of herbal plants on rumen fermentation, methane gas emissions, in vitro nutrient digestibility, and population of protozoa oleh Antonius Antonius, Roni Pazla, Ezi Masdia Putri, Windu Negara, Nursanti Laia, Muhammad Ridla, Sri Suharti, Anuraga Jayanegara, Sharli Asmairicen, Leni Marlina, Yoselanda Marta