Variation in MERm Between and Within Cows
Considerable variation was observed among cows in mean values for MERm over the 5-mo monitoring period. The frequency of MERm means, averaged for each individual cow across the study, followed a normal distribution (Figure 1), with an overall mean of 2.07 (SD 0.629) g of CH4/min and a range from 0.57 to 3.6 g of CH4/min.(peak area and frequency) were used to calculate individual daily means for methane emission rate during milking (MERm), as described by Garnsworthy et al. (2012).