The possible influence of intra-ruminal sulphur hexafluoride release rates on calculated methane emissions from cattle
Bibliographic record
Abstract
Estimates of methane (CH 4 ) production from grazing animals are routinely made using the sulphur hexafluoride (SF 6 ) tracer technique. While this technique is generally regarded as useful, some investigators report a higher variability in measurements when compared with calorimetry. The SF 6 technique is a marker dilution method in which a known release rate of SF 6 from an intra-ruminal permeation tube is used to calculate CH 4 emissions from the ratio of SF 6 :CH 4 in expired breath. The release rate of SF 6 is unique for each tube, and although calculated CH 4 emissions should be independent of SF 6 release rate, an analysis of research conducted in New Zealand has suggested a possible influence of SF 6 release rate upon calculated CH 4 emissions. A modified cross-over design, with two groups of six steers given either one (2.878 mg SF 6 d -1 ) or two (7.336 mg SF 6 d -1 ) permeation tubes and offered either energy maintenance (M) or 2 × M levels of feed intake was undertaken to determine the effect of SF 6 release rate and intake on calculated CH 4 emissions. A high SF 6 release rate elevated the calculated CH 4 emission per day (P < 0.001) and per kg dry matter intake (kg DMI) by 19% (P < 0.001) irrespective of the level of intake. Release rate of SF 6 can affect the calculated CH 4 emissions from animals when employing the SF 6 tracer technique. Key words: Methane, SF 6 tracer technique, cattle, variability, feeding level
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".