“…Out of 41 papers, 17 articles were excluded for the following reasons: summary papers (4), no CH 4 emission measurements (2), no monensin/treatment effect results reported (2), without control measurements (3), conference papers as there were duplicate publications of the similar study (2), conference paper only reported an abstract, simulation papers (2), and paper that investigated the effects of monensin when mixed with other feed additives. The final database had a total of 24 papers that met the criteria and remained in the database; however, 13 were related to beef cattle [ 29 , 36 , 38 , 39 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ] and 11 were related to dairy cattle [ 8 , 9 , 28 , 30 , 31 , 32 , 33 , 34 , 53 , 54 , 55 ]. Then, beef cattle papers were excluded from the database.…”