Methane emissions by Charolais cows grazing a monospecific pasture of timothy at four stages of maturity
Bibliographic record
Abstract
In order to examine the relationship between herbage maturity and methane (CH 4 ) emission under conditions which minimized opportunities for selective grazing, six 8-yr-old, dry and early-pregnant Charolais cows [712 ± 22.7 kg liveweight (LW)] were grazed on a mono-specific pasture of timothy at four stages of maturity: early vegetative, heading, flowering, and senescence. Daily CH 4 production was measured during 7 d using the sulfur hexafluoride (SF 6 ) tracer-gas technique. Organic matter intake (OMI) was determined from fecal output estimated by Yb 2 O 3 dosing and feed digestibility (OMD) estimated using a fecal N index. The OMD (%) decreased (P < 0.05) from 77.6 at early vegetative to 56.2 at senescence, but no cow effect upon OMD was observed. The OMI (14.8 g kg -1 LW) and CH 4 production (273 g d -1 ) were higher (P < 0.05) at heading than at the other stages of maturity. The proportion of gross energy intake (GEI) lost in CH 4 did not differ with maturity (mean 6.4% of GEI). Cow effects upon OMI and CH 4 emission were significant (P < 0.05). CH 4 production (g d -1 ) was not related to diet chemical composition or OMD, but was correlated with digestible neutral detergent fiber (NDF) intake (kg d -1 ) (r = 0.61, P < 0.01). Across all stages of maturity between-cow variation explained 54 to 70% of the total variation in CH 4 production. Key words: Methane, cattle, animal variation, timothy, phenology, selective grazing
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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 source (direct Gemma or distilled Codex), 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".