Selenium uptake by ruminal microorganisms from organic and inorganic sources in dairy cows
Bibliographic record
Abstract
The objectives of this study were (i) to determine the amount of time required for microbial Se concentration to reach a plateau and the half-life of Se in the ruminal microorganisms (exp. 1) and (ii) to compare Se uptake by ruminal microorganisms from organic and inorganic sources (exp. 2). In exp. 1, four dry ruminally cannulated Holstein dairy cows (863 ± 98 kg of BW, mean ± SD) housed in a tie-stall facility were used in a completely randomized design with a 14-d adaptation and 9-d measurement period. Cows were offered 10 kg of timothy hay (divided in 12 equal portions and delivered at 2-h intervals) supplemented with 500 g of dry-cow mineral and vitamin premix at 0800 daily. The treatments were inorganic and organic Se that were each enriched with Se stable isotopes (inorganic 82Se and organic 77Se Sel-Plex®). The Se treatments were supplemented at 0.3 mg kg-1 DM and administered directly into the rumen under the rumen mat every 6 h. Rumen samples (both fluid and solid) were collected before treatment administration every 6 h and the microbial fraction were isolated. On day 9 after the administration of the last dose of tracer, 600 mL of ruminal content was collected every hour for 24 h to determine Se half-life in the ruminal microorganisms. In exp. 2, treatments were administered for only 5 d, i.e., 2 d to reach a plateau in Se concentration and 3 d of collection and measurement. The cows were supplemented with the control premix (no added Se) during the adaptation period and with the organic and inorganic Se premixes during the treatment and measurements period. In exp. 1, microbial 77Se concentration reached a plateau in 2 d, whereas 82Se reached a plateau in 1 d. The half-life of Se in the ruminal microorganisms was 16 and 48 h, for 77Se and 82Se, respectively. In exp. 2, 77Se uptake by ruminal microorganisms was higher (P < 0.05) than that for 82Se and averaged 330 ± 7.7 and 125 ± 3.9 µg kg-1 for 77Se and 82Se, mean ± SEM, respectively. The results show that inorganic Se has a lower ruminal microbial uptake than organic Se sources. Key words: Microbial selenium uptake, dairy cow
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".