PSXII-30 Changes in Ruminal Digesta and Ruminal Ammonia-N Concentration with Differing Durations Feed Restriction for Sheep
Bibliographic record
Abstract
Abstract During transient periods of feed restriction (FR), ruminal ammonia-N (NH3-N) concentrations and fluid volume may parallel the reduction in feed and water intake. However, changes in ruminal digesta characteristics and NH3-N during FR have not been characterized. Thus, the objective was to determine how FR duration impacts ruminal digesta weight and the liquid and solid fractions, and ruminal NH3-N concentration. Lambs (n = 9 wethers and 12 rams, stratified by BW and castration status) were fed ad libitum (AL, n = 7) or subjected to 5-d (FR5, n = 7) or 10-d of FR (FR10, n = 7) at 30% of AL intake. Lambs were killed 4 h post-feeding to excise the gastrointestinal tract and ruminal digesta was weighed. Sub-samples of digesta were collected for separation into solid and liquid fractions using a winepress, used for DM determination, and another was strained and preserved with sulfuric acid to analyze ruminal NH3-N concentration. Data were analyzed with PROC GLIMMIX (SAS 9.4) with the fixed effect of treatment and random effects of lamb specified to the R-sided matrix. Linear regression (PROC REG) was used to evaluate the relationship between ruminal NH3-N concentration and quantity relative to ruminal fluid weight and PROC CORR was used to generate Pearson correlation coefficients. The ruminal digesta weight did not differ (P = 0.97) among treatments but AL ruminal digesta was drier (P < 0.01) than FR5 and FR10 digesta (40.2% decrease in DM% relative to AL). As such, FR5 and FR10 had 0.7 ± 0.16 kg less (P = 0.01) ruminal solids than AL while they tended to have more (P = 0.09) ruminal fluid. Ruminal NH3-N concentration was greater (P < 0.01) for FR5 and FR10 compared with AL (2.4 and 2.0 vs. 0.4 ± 0.52 mg/dL, respectively). The quantity of ruminal NH3-N (mg) followed the same pattern with FR5 and FR10 having, on average, 51.5 ± 18.39 mg NH3-N more (P < 0.01) in their ruminal fluid than AL. The quantity of ruminal NH3-N was strongly correlated (ρ = 0.87, P < 0.01) to the total ruminal fluid such that 75% of the variance was explained by the relationship. The strength of the correlation (ρ = 0.81, R2 = 0.66, P < 0.01) between ruminal NH3-N concentration and total ruminal fluid was slightly lesser, but the two parameters were still strongly associated. From these data, we surmise that FR is associated with a reduction in ruminal DM content and may increase ruminal liquid that corresponds to increased ruminal NH3-N, independent of the duration of exposure.
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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) | 0.002 | 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".