486 Evaluation of beef heifers fed four different diets when selected for divergent digestible fiber intake
Bibliographic record
Abstract
Abstract The objective of this study was to evaluate the factors which influence intake and fiber digestion efficiency of beef cattle previously selected for high or low digestible neutral detergent fiber (NDF) intake (DFI; g/kg BW0.75). Angus × Hereford cross heifers [n = 16; initial body weight (BW) = 584 ± 32.2 kg] previously classified as either high or low DFI when fed a high-forage diet (n = 8/treatment) were individually housed and fed one of 4 diets for ad libitum intake using a sequential offering of diets over four consecutive 28-d period. Diets included: 1) 100% grass hay; 2) 100% mature alfalfa hay; 3) 90% dry rolled barley + 10% alfalfa hay; and 4) 90% dry rolled barley + 10% grass hay (DM basis). Individual animal feed intake was recorded daily in addition to weekly BW. Rumen digesta samples were collected prior to feeding and 6 h after for 2 d within each period and analyzed for SCFA and NH3-N concentrations, and total rumen protozoa counts and identification. High DFI heifers had similar (P > 0.11) DMI compared with low DFI heifers in periods 1, 3, and 4, but had a tendency for greater DMI in period 2 and NDF intake during period 2 and 3 (7.84 vs. 7.07 kg, P = 0.07; 4.71 vs. 4.27 kg, P = 0.08; 2.56 vs. 2.28 kg, P = 0.10). ADG was greater for high DFI during the first two periods (0.61 vs. 0.13, P = 0.04; 0.44 vs. -0.09, P = 0.02); moreover, high DFI cattle finished the study with a heavier BW (708 vs. 661 kg, P = 0.04). Total SCFA concentrations before and 6 h after feeding did not differ (P ≥ 0.36) between treatments. NH3-N concentrations were not different before feeding during period 1, 3, and 4, but were greater for high DFI heifers during period 2 (9.85 vs. 8.39, P = 0.04). Additionally, there were no differences in NH3-N concentrations 6 h after feeding during any period. No differences were observed (P > 0.25) between treatment groups for total rumen protozoa counts for periods 1 and 2; however, there was a tendency for a greater proportion of Isotrichia before feeding during period 1 (3.67 vs. 2.41%, P = 0.07). In conclusion, differences in intake and the small changes in ruminal fermentation parameters only partially explain the differences in ADG observed between high and low DFI heifers.
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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) | 0.001 | 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".