Replacing alfalfa silage with corn silage in dairy cow diets: Effects on enteric methane production, ruminal fermentation, digestion, N balance, and milk production
Bibliographic record
Abstract
The objective of this study was to determine the effects of replacing alfalfa silage (AS) with corn silage (CS) in dairy cow total mixed rations (TMR) on enteric CH4 emissions, ruminal fermentation characteristics, apparent total-tract digestibility, N balance, and milk production. Nine ruminally cannulated lactating cows were used in a replicated 3×3 Latin square design (32-d period) and fed (ad libitum) a TMR [forage:concentrate ratio of 60:40; dry matter (DM) basis], with the forage portion consisting of either alfalfa silage (0% CS; 56.4% AS in the TMR), a 50:50 mixture of both silages (50% CS; 28.2% AS and 28.2% CS in the TMR), or corn silage (100% CS; 56.4% CS in the TMR). Increasing the CS proportion (i.e., at the expense of AS) in the diet was achieved by decreasing the corn grain proportion and increasing that of soybean meal. Intake of DM and milk yield increased quadratically, whereas DM digestibility increased linearly as the proportion of CS increased in the diet. Increasing the dietary CS proportion resulted in changes (i.e., lower ruminal pH and acetate:propionate ratio, reduced fiber digestibility, decreased protozoa numbers, and lower milk fat and higher milk protein contents) typical of those observed when cows are fed high-starch diets. A quadratic response in daily CH4 emissions was observed in response to increasing the proportion of CS in the diet (440, 483, and 434 g/d for 0% CS, 50% CS, and 100% CS, respectively). Methane production adjusted for intake of DM, and gross or digestible energy was unaffected in cows fed the 50% CS diet, but decreased in cows fed the 100% CS diet (i.e., quadratic effect). Increasing the CS proportion in the diet at the expense of AS improved N utilization, as reflected by the decreases in ruminal NH3 concentration and manure N excretion, suggesting low potential NH3 and N2O emissions. Results from this study, suggest that total replacement of AS with CS in dairy cow diets offers a means of decreasing CH4 output and N losses. However, the reduction in fiber degradation and the resulting increase in volatile solids content of the manure may lead to increased CH4 emissions from manure storage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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 teacher head, 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".