The data of Kurihara et al. (Reference Kurihara, Magner, Hunter and McCrabb1999) have been used in estimating emissions of CH₄ of tropical cattle consuming warm season grasses. These data, obtained using Brahman crossbred cattle fed ad libitum on hays of the grasses Dichanthium aristatum (Angleton grass) and Chloris gayana (Rhodes grass), or a grain-based diet, indicated that CH₄ yield per intake of gross energy was higher than for cattle eating temperate forages.

CSIRO has now discovered a systematic error of +17 % in calculation of these CH₄ emission values as a result of an algorithm which used an incorrect chamber volume. The error does not apply to O₂ or CO₂ data, as these were corrected from gas exchange data resulting from combustion of a known amount of ethanol.

Because of the use made of the data of Kurihara et al. (Reference Kurihara, Magner, Hunter and McCrabb1999) in the Australian greenhouse gas inventories of greenhouse emissions (e.g. National Greenhouse Gas Inventory Committee, 2006), I consider it necessary to correct the public record on behalf of CSIRO. Accordingly recalculations of the pertinent data are presented in Table 1.

Table 1 Methane production by cattle according to diet

DOMI, digestible organic matter intake; GEI, gross energy intake; DEI, digestible energy intake.

* Not calculated, as cattle experienced live-weight loss.

^a,b,c Mean values within a row not sharing a common superscript letter were significantly different, P < 0·05.

The relationship between methane production (y, g/d) and dry matter intake (x, kg/d) for the two tropical grasses depicted in Figure 2 of Kurihara et al. (Reference Kurihara, Magner, Hunter and McCrabb1999) becomes:

These corrections do not alter the validity of conclusions of Kurihara et al. (Reference Kurihara, Magner, Hunter and McCrabb1999): “ that the relationships between CH₄ production, energy utilization and live-weight change of cattle fed on tropical forages differ from those of cattle fed on diets based on temperate forages”.

This communication has been approved by all authors of the original publication.