Strong differences in the CH4 emission from feces of grazing steers submitted to different feeding schedules

•Using static chambers for monitoring of methane emission from fecal matter.•Variation of methane emission from feces during the daytime.•Feces of steers on different feeding schedules used in the Argentine pastoral system.•Strong differences between steers grazing during morning and afternoon.

When studying the effects of changing the feeding schedule of Holstein steers grazing in a pure oat field, it was observed that the fecal matter of animals grazing in the morning emitted much more methane than that of steers grazing in the afternoon. Feces from two groups of 10 steers with different feeding schedules were collected on the same day and separately mixed to form two composite samples. Then, five sub-samples of each composite sample were randomly placed on the oat field and CH4 emissions were measured after deposition for 27 days. The difference in the emissions was in qualitative agreement with the pronounced loss of organic matter from the morning samples during the experimental period.