Macroscopic anatomy of the omasum of free‐ranging moose (<i>Alces alces</i>) and muskoxen (<i>Ovibos moschatus</i>) and a comparison of the omasal laminal surface area in 34 ruminant species
Bibliographic record
Abstract
Abstract The function of the ‘third compartment’ of the ruminant forestomach, the omasum, has been debated for a long time. To date, it is assumed that its major function is fluid reabsorption. In order to investigate differences in this organ between ruminant feeding types, we first compared macroscopic measurements of the omasa of free‐ranging muskoxenOvibos moschatus[n=6, mean body mass (BM) 207 kg, range 180–221], a grazer, and free‐ranging mooseAlces alces(n=11, mean BM 291 kg, range 144–418), a strict browser. Despite the similar BM range, omasa of muskoxen contained more ingesta, had a higher empty organ weight, had more third‐ and fourth‐order laminae, and represented a higher proportion of the total forestomach weight. In particular, the surface area of the omasal leaves – the area available for fluid absorption – was significantly larger in muskoxen (10 933±940 cm2) than in moose (2228±885 cm2). In order to test whether the difference in available surface area is a true functional correlate of feeding type, additional data on the omasal laminar surface area were generated for 83 individuals of 19 species. These data were supplemented with data on 13 additional species from the literature. The percentage of grass (%grass) in the natural diet was used to characterize the feeding type; the phylogenetic tree used for a controlled statistical evaluation was entirely based on mitochondrial DNA information. Regardless of phylogenetic control in the statistical treatment, there was a significant positive correlation of both BM and %grass in the natural diet with omasal laminar surface area. The data suggest that certain ruminant species that ingest more grass have larger omasal leaf surface areas, possibly indicating a higher need for water reabsorption distal to the ruminoreticulum, which could be explained as a consequence of the more distinct rumen contents stratification in these species.
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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 | 0.001 | 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".