Effects of supplements of folic acid, vitamin B12, and rumen-protected methionine on whole body metabolism of methionine and glucose in lactating dairy cows
Bibliographic record
Abstract
The present experiment was undertaken to determine the effects of dietary supplements of rumen-protected methionine and intramuscular injections of folic acid and vitamin B(12), given 3 wk before to 16 wk after calving, on glucose and methionine metabolism of lactating dairy cows. Twenty-four multiparous Holstein cows were assigned to 6 blocks of 4 cows each according to their previous milk production. Within each block, 2 cows were fed a diet estimated to supply methionine as 1.83% metabolizable protein, equivalent to 76% of methionine requirement, whereas the 2 other cows were fed the same diet supplemented daily with 18 g of rumen-protected methionine. Within each diet, the cows were administrated either no vitamin supplement or weekly intramuscular injections of 160 mg of folic acid plus 10 mg of vitamin B(12.) To investigate metabolic changes at 12 wk of lactation, glucose and methionine kinetics were measured by isotope dilution using infusions of 3[U-(13)C]glucose, [(13)C]NaHCO(3) and 3[1-(13)C,(2)H(3)] methionine. Milk and plasma concentrations of folic acid and vitamin B(12) increased with vitamin injections. Supplementary B-vitamins increased milk production from 34.7 to 38.9 +/- 1.0 kg/d and increased milk lactose, protein, and total solids yields. Whole-body glucose flux tended to increase with vitamin supplementation with a similar quantitative magnitude as the milk lactose yield increase. Vitamin supplementation increased methionine utilization for protein synthesis through increased protein turnover when methionine was deficient and through decreased methionine oxidation when rumen-protected methionine was fed. Vitamin supplementation decreased plasma concentrations of homocysteine independently of rumen-protected methionine feeding, although no effect of vitamin supplementation was measured on methionine remethylation, but this could be due to the limitation of the technique used. Therefore, the effects of these B-vitamins on lactation performance were not mainly explained by methionine economy because of a more efficient methylneogenesis but were rather related to increased glucose availability and changes in methionine metabolism.
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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) | 0.001 | 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 | 0.001 |
| 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".