Effects of various sources of unsaturated oil on ruminal fermentation characteristics, nutrient digestion, enteric methane emissions, nitrogen partitioning, and milk production in dairy cows
Bibliographic record
Abstract
The objective of this study was to investigate the effects of dietary inclusion of different sources of unsaturated vegetable oil on ruminal fermentation characteristics, nutrient digestion, enteric CH 4 emissions, nitrogen partitioning, milk production, and milk fatty acid composition. Eight multiparous ruminally cannulated Holstein cows were used in a duplicated 4 × 4 Latin square design (28-d periods) balanced for residual effects. Treatments consisted of a TMR based on alfalfa silage and corn silage (forage:concentrate ratio 52:48; DM basis) either not supplemented (CTL), or supplemented (4% of DM) with either sunflower (SUN, 67.5% cis -9 18:1), safflower (SAF, 74.6% cis -9, cis -12 18:2), or linseed (LSO, 54.9% cis -9, cis -12, cis -15 18:3) oil. The inclusion of the vegetable oil was performed primarily at the expense of another energy source (i.e., corn grain). Feeding the oil-supplemented diets decreased DMI (−1.2 kg/d, on average) and increased apparent total-tract digestibility of CP, compared with the CTL. However, no changes were noted in digestibility of DM, OM, NDF, gross energy, or the effective ruminal degradability of DM (i.e., in situ technique). Milk yield decreased only when feeding SUN (−3.3 kg/d) or SAF (−4.1 kg/d), compared with the CTL. Milk fat yield decreased when using SAF (−0.44 kg/d, −38%), SUN (−0.32 kg/d, −28%), and LSO (−0.21 kg/d, −18%), compared with the CTL. Milk protein yield was reduced with SUN (−9%) and SAF (−7%) compared with the CTL but was unaffected by LSO. The content of MUN decreased with oil supplementation by 28%, 20%, and 10% for LSO, SAF, and SUN, respectively. In contrast, the efficiency of dietary N use for milk N secretion was not affected when cows were fed the oil-supplemented diets. Relative to N intake, fecal N decreased, whereas urinary N increased with oil-supplemented diets. Oil supplementation did not alter enteric daily CH 4 production (SF 6 tracer technique) or yield. In the present study, the oils differing in unsaturation level did not change overall ruminal fermentation characteristics, OM digestibility, or CH 4 production. Feeding the oil-based diets had no effect on N balance but shifted N excretion from feces to urine. Cows consuming the oil-supplemented diets exhibited reduced milk fat yield, depending on the unsaturation level, with a more pronounced decrease with SAF (i.e., a source of cis -9, cis -12 18:2), followed by SUN (i.e., a source of cis -9 18:1) and LSO (i.e., a source of cis -9, cis -12, cis -15 18:3).
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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 | 0.001 | 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".