Methanogen prevalence throughout the gastrointestinal tract of pre-weaned dairy calves
Bibliographic record
Abstract
The methanogenic community throughout the gastrointestinal tract (GIT) of pre-weaned calves has not been well studied. The current study firstly investigated the distribution and composition of the methanogenic community in the rumen, ileum, and colon of 3-4 week-old milk-fed dairy calves (n = 4) using 16S rRNA gene clone library analysis. The occurrence of methanogens in the GIT of pre-weaned calves was further validated by using PCR-denaturing gradient gel electrophoresis (PCR-DGGE), and quantitative real-time PCR (qPCR) was applied to quantify the methanogenic community in the rumen, jejunum, ileum, cecum, colon and rectum of 8 3-4 week old animals. Both cloning libraries and PCR-DGGE revealed that phylotypes close to Methanobrevibacter were the main taxon along the GIT in pre-weaned sucking calves. The composition and abundance of methanogens varied significantly among individual animals, suggesting that host conditions may influence the composition of the symbiotic microbiota. Segregation of methanogenic communities throughout the GIT was also observed within individual animals, suggesting possible functional differences among methanogens residing in different GIT regions. This is the first study to analyze methanogenic communities throughout the GIT of milk-fed newborn dairy calves and reveal both their diversity and abundance. The identification of methanogens in the lower GIT of pre-weaned dairy calves warrants further investigation to better define methanogen roles in GIT function and their impact on host metabolism and health.
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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 | 0.001 |
| 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 | 0.001 | 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".