568 Effects of encapsulated nitrate on growth performance, nitrate toxicity, and enteric methane emissions in feedlot beef steers: Backgrounding phase
Bibliographic record
Abstract
A backgrounding feedlot study was conducted to examine the effects of feeding encapsulated calcium ammonium nitrate (EN) on growth, enteric methane production, and nitrate (NO3-) toxicity in beef cattle. A total of 108 crossbred steers (292 ± 18 kg) were blocked by BW and randomly assigned to 18 pens. The pens (experimental unit; 6 animals per pen) received 3 dietary treatments: Control, a backgrounding diet supplemented with urea (0.2% NO3-and 0.9% urea in dietary DM); 1.25% EN, control diet supplemented with 1.25% EN (1.2% NO3-) in dietary DM, which partially replaced urea; or 2.5% EN, control diet supplemented with 2.5% EN (2.3% NO3-) in dietary DM, fully replacing urea. Twenty four steers were allocated to additional 4 pens and randomly assigned to 1 of the above 3 dietary treatments plus a fourth treatment: 2.3% UEN, control diet supplemented with 2.3% unencapsulated NO3-(UEN; 2.4% NO3-) fully replacing urea. Animals in the additional 4 pens were used for methane measurement in respiratory chambers and the pens (except UEN) were also part of the performance study (i.e., n = 7 pens/treatment). The experiment was conducted for 91 d in a randomized complete block design. During the experiment, DMI was not affected by inclusion of EN in the diet. Changes in BW, ADG, and gain:feed were not observed (P 0.57) by feeding EN. Methane production (g/d) tended to decrease (P= 0.099) by NO3-(188, 174, 156, and 152 g/d for Control, 1.25%, 2.5% EN, and UEN, respectively), but yield (g/kg DMI) did not differ (P= 0.56) among treatments. Inclusion of EN in the diet increased (P 0.02) sorting of the diets in favor of large and medium particles and against small and fine particles resulting in considerable increases in NO3-concentrations of orts without affecting DMI. Plasma NO3-and NO2-concentrations increased (P 0.05) for EN compared with Control in a dose response manner, but blood methemoglobin levels were below the detection limit. Nitrate concentration in fecal samples slightly increased (from 0.01% to 0.14%;P<0.01) with increasing levels of EN in the diet. In conclusion, EN can be used as a feed additive replacing urea in beef cattle diets during the backgrounding phase without NO3-intoxication or any negative effects on growth performance. In addition, the study confirmed that feeding EN tended to decrease enteric methane production in the long term.
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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 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".