Effects of dietary protein levels and 2‐methylbutyrate on ruminal fermentation, nutrient degradability, bacterial populations and urinary purine derivatives in Simmental steers
Bibliographic record
Abstract
Summary The objective of this study was to evaluate the effects of dietary crude protein ( CP ) levels and 2‐methylbutyrate ( MB ) supplementation on ruminal fermentation, bacterial populations, microbial enzyme activity and urinary excretion of purine derivatives ( PD ) in Simmental steers. Eight ruminally cannulated Simmental steers, averaging 18 months of age and 465 ± 8.6 kg of body weight ( BW ), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Low protein (98.5 g CP /kg dry matter [ LP ] or high protein (128.7 g CP /kg dry matter [ HP ]) diets were fed with MB supplementation (0 g [ MB −] or 16.8 g steer −1 day −1 [ MB +]). Steers were fed a total mixed ration with dietary corn straw to concentrate ratio of 50:50 (dry matter [ DM ] basis). The CP × MB interaction was observed for ruminal total VFA , molar proportions of acetate and propionate, acetate to propionate ratio, ammonia‐N, effective degradability of neutral detergent fibre ( NDF ) and CP , microbial enzyme activity, bacterial populations and total PD excretion ( p < .05). Ruminal pH decreased ( p < .05), but ruminal total VFA concentration increased ( p < .05) with increasing dietary CP level or MB supplementation. Acetate molar proportion increased ( p = .043) with MB supplementation, but was not affected by dietary CP level. Propionate molar proportion decreased ( p < .05) with increasing dietary CP level or MB supplementation. Consequently, acetate‐to‐propionate ratio increased ( p = .001) with MB supplementation, but was not affected by dietary CP level. Ruminal ammonia‐N content increased ( p = .034) with increasing dietary CP level, but decreased ( p = .012) with MB supplementation. The effective degradability of NDF and CP increased ( p < .05) with increasing dietary CP level or MB supplementation. Microbial enzyme activity, bacterial populations and total PD excretion also increased ( p < .05) with increasing dietary CP level or MB supplementation. The results indicated that ruminal fermentation, nutrient degradability, microbial enzyme activity, ruminal bacterial populations and microbial protein synthesis improved with increasing dietary CP level or MB supplementation in steers.
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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 | 0.000 |
| 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".