Ruminal dry matter disappearance, total gas and methane production, and fermentation parameters as affected by fat and protein concentration in by-product supplemented grass hay-based diets
Bibliographic record
Abstract
Context Dietary manipulation is an important means to mitigate methane emissions; however, relatively few options exist for forage-based diets. Aims This batch culture study evaluated the effects of crude protein (CP) and fat concentration on ruminal DM disappearance (DMD), total gas (GP) and methane production, and ruminal fermentation in grass hay-based diets supplemented with a range of by-product feeds. Methods Eight treatments provided low or high CP (8 or 12% diet DM, respectively), with range of fat concentrations (1.8–6.0% diet DM), and included: control (grass hay only); corn distillers grains with solubles at 8% (CDDGS8) and 12% CP (CDDGS12); flax at 8% (FS8) and 12% CP (FSCDDGS12); canola meal at 8% (Can8); and sunflower screenings from Winkler (SFW8) or Deloraine (SFD8) at 8%. Data were analysed as a randomised complete block design, with fixed effect of treatment and random effects of block and treatment × block. Comparisons were performed between: (1) control and mean of by-product treatments, (2) low and high CP treatments, (3) CDDGS treatments, (4) FS treatments, and (5) SF treatments. Low- and high-fat treatments at both CP concentrations, and the means of CDDGS and FS treatments differing in fat concentrations were also compared. Key results The DMD did not differ between control and by-product treatments; however, DMD was lower (P < 0.001) in treatments with 8% compared with 12% CP, and was higher (P ≤ 0.009) with low fat compared with high fat, regardless of CP. Total GP was not affected by CP; however, at low CP, treatments with higher fat had lower GP (P ≤ 0.015). Methane production did not differ between any of the low and high CP treatments, but was higher (P ≤ 0.003) in the low-fat compared with high-fat treatments, regardless of CP, as well as in FS versus CDDGS and SFD versus SFW. Conclusions Higher CP increased DMD in vitro, but did not affect GP, methane or fermentation. Implications Higher dietary fat can mitigate enteric methane production, but can negatively impact DMD in grass hay-based diets, which is an important consideration in terms of animal performance.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".