Daning D R A, Widyobroto B P, Hanim C, Muhlisin and Yusiati L M 2022 Effect of galangal essential oils on enzyme activity and nutrient digestibility in in vitro rumen fermentation. Livestock Research for Rural Development. Volume 34, Article #114. Retrieved , from http://www.lrrd.org/lrrd34/12/34114lies.html