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This dataset accompanies a publication titled "Dynamics of enteric methane production during and after the inclusion of a bromoform-based feed additive in the diet of beef steers" (abstract below).
Methane emissions from cattle were measured in 10x respiration chambers. This data has been processed from raw gas concentrations and airflow measurements into the units of g CH4/min. Measurements from each chamber are recorded every 16.5 minutes. The measurement period is usually ~23 h for each day they are in chambers, with a short period of time for cleaning and feeding prior to re-starting chamber measurements. These data were used for fitting non-linear models to determine the temporal changes in the onset and withdrawal of a bromoform-based feed additive. See paper and abstract for details.
Abstract
The aim of this experiment was to investigate the dynamics of enteric methane production from steers before, during, and after the inclusion of a bromoform-based feed additive in their diet. Twenty Bos taurus steers were fed ad libitum a 60% tempered barley feedlot transition ration (DM basis) and spent two 9-day measurement phases in open-circuit respiration chambers to measure methane emissions. The first phase included 2 days of baseline measurements with no bromoform-based feed additive, followed by a 7-day Onset period during which they were fed a bromoform-based feed additive at two bromoform concentrations: High (40 mg/kg DM) or Low (20 mg/kg DM) mixed into the feed. Steers were then fed their treatments in pens for a further 9 days, after which the steers returned to the respiration chambers for a second 9-day phase. This included a 2-day Pre-Withdrawal period with bromoform feeding and a 7-day Withdrawal period without bromoform. For steers on the High treatment, methane production (MP) and methane yield (MY) were lower in the Onset and Pre-Withdrawal periods when the bromoform-based feed additive was included in the diet (P < 0.05), relative to both the Baseline and Withdrawal periods, where the bromoform was not included. Mean MP and MY were 97% lower in the Onset period relative to Baseline for steers on the High treatment, and these values returned to baseline levels by the end of the Withdrawal period. For steers on the Low treatment, the MP and MY in the Onset period were 67 and 65% lower than the Baseline, respectively. However, there was a significant increase in MP and MY during the 10-day period between the end of the Onset period and the start of the Pre-Withdrawal period. Both MP and MY then returned to Baseline levels by the end of the Withdrawal period. The findings of this study show feeding the bromoform-based feed additive to beef steers results in a rapid methane reduction, reaching up to 97% abatement within 2 days, depending on dose. Steers that maintained normal feeding behaviour had a similar reduction in MP when fed either a High or a Low dose of bromoform, but this reduction occurred sooner in the High steers (16.8 h) than in the Low (55.7 h). |
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